Move sequencer sources from blenkernel

This is first step of refactoring task T77580.
Next step will be breaking up files into smaller ones.

Reviewed By: sergey, brecht

Differential Revision: https://developer.blender.org/D8492

1 files changed, 6193 insertions, 0 deletions

diff --git a/source/blender/sequencer/intern/sequencer.c b/source/blender/sequencer/intern/sequencer.c
new file mode 100644
index 00000000000..b8ccdec0902
--- /dev/null
+++ b/source/blender/sequencer/intern/sequencer.c
@@ -0,0 +1,6193 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * - Blender Foundation, 2003-2009
+ * - Peter Schlaile <peter [at] schlaile [dot] de> 2005/2006
+ */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include <math.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_anim_types.h"
+#include "DNA_mask_types.h"
+#include "DNA_movieclip_types.h"
+#include "DNA_object_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_sequence_types.h"
+#include "DNA_sound_types.h"
+#include "DNA_space_types.h"
+#include "DNA_windowmanager_types.h"
+
+#include "BLI_fileops.h"
+#include "BLI_linklist.h"
+#include "BLI_listbase.h"
+#include "BLI_math.h"
+#include "BLI_path_util.h"
+#include "BLI_session_uuid.h"
+#include "BLI_string.h"
+#include "BLI_string_utf8.h"
+#include "BLI_threads.h"
+#include "BLI_utildefines.h"
+
+#ifdef WIN32
+#  include "BLI_winstuff.h"
+#else
+#  include <unistd.h>
+#endif
+
+#include "BLT_translation.h"
+
+#include "BKE_anim_data.h"
+#include "BKE_animsys.h"
+#include "BKE_fcurve.h"
+#include "BKE_global.h"
+#include "BKE_idprop.h"
+#include "BKE_image.h"
+#include "BKE_layer.h"
+#include "BKE_lib_id.h"
+#include "BKE_main.h"
+#include "BKE_mask.h"
+#include "BKE_movieclip.h"
+#include "BKE_report.h"
+#include "BKE_scene.h"
+#include "BKE_sequencer.h"
+#include "BKE_sequencer_offscreen.h"
+
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
+
+#include "RNA_access.h"
+
+#include "RE_pipeline.h"
+
+#include <pthread.h>
+
+#include "IMB_colormanagement.h"
+#include "IMB_imbuf.h"
+#include "IMB_imbuf_types.h"
+#include "IMB_metadata.h"
+
+#include "BKE_context.h"
+#include "BKE_sound.h"
+
+#include "RE_engine.h"
+
+#ifdef WITH_AUDASPACE
+#  include <AUD_Special.h>
+#endif
+
+/* mutable state for sequencer */
+typedef struct SeqRenderState {
+  LinkNode *scene_parents;
+} SeqRenderState;
+
+static ImBuf *seq_render_strip_stack(const SeqRenderData *context,
+                                     SeqRenderState *state,
+                                     ListBase *seqbasep,
+                                     float cfra,
+                                     int chanshown);
+static ImBuf *seq_render_preprocess_ibuf(const SeqRenderData *context,
+                                         Sequence *seq,
+                                         ImBuf *ibuf,
+                                         float cfra,
+                                         clock_t begin,
+                                         bool use_preprocess,
+                                         const bool is_proxy_image);
+static ImBuf *seq_render_strip(const SeqRenderData *context,
+                               SeqRenderState *state,
+                               Sequence *seq,
+                               float cfra);
+static void seq_free_animdata(Scene *scene, Sequence *seq);
+static ImBuf *seq_render_mask(const SeqRenderData *context, Mask *mask, float nr, bool make_float);
+static int seq_num_files(Scene *scene, char views_format, const bool is_multiview);
+static void seq_anim_add_suffix(Scene *scene, struct anim *anim, const int view_id);
+
+static ThreadMutex seq_render_mutex = BLI_MUTEX_INITIALIZER;
+
+/* **** XXX ******** */
+#define SELECT 1
+ListBase seqbase_clipboard;
+int seqbase_clipboard_frame;
+
+SequencerDrawView sequencer_view3d_fn = NULL; /* NULL in background mode */
+
+#if 0 /* unused function */
+static void printf_strip(Sequence *seq)
+{
+  fprintf(stderr,
+          "name: '%s', len:%d, start:%d, (startofs:%d, endofs:%d), "
+          "(startstill:%d, endstill:%d), machine:%d, (startdisp:%d, enddisp:%d)\n",
+          seq->name,
+          seq->len,
+          seq->start,
+          seq->startofs,
+          seq->endofs,
+          seq->startstill,
+          seq->endstill,
+          seq->machine,
+          seq->startdisp,
+          seq->enddisp);
+
+  fprintf(stderr,
+          "\tseq_tx_set_final_left: %d %d\n\n",
+          seq_tx_get_final_left(seq, 0),
+          seq_tx_get_final_right(seq, 0));
+}
+#endif
+
+static void sequencer_state_init(SeqRenderState *state)
+{
+  state->scene_parents = NULL;
+}
+
+int BKE_sequencer_base_recursive_apply(ListBase *seqbase,
+                                       int (*apply_fn)(Sequence *seq, void *),
+                                       void *arg)
+{
+  Sequence *iseq;
+  for (iseq = seqbase->first; iseq; iseq = iseq->next) {
+    if (BKE_sequencer_recursive_apply(iseq, apply_fn, arg) == -1) {
+      return -1; /* bail out */
+    }
+  }
+  return 1;
+}
+
+int BKE_sequencer_recursive_apply(Sequence *seq, int (*apply_fn)(Sequence *, void *), void *arg)
+{
+  int ret = apply_fn(seq, arg);
+
+  if (ret == -1) {
+    return -1; /* bail out */
+  }
+
+  if (ret && seq->seqbase.first) {
+    ret = BKE_sequencer_base_recursive_apply(&seq->seqbase, apply_fn, arg);
+  }
+
+  return ret;
+}
+
+/*********************** alloc / free functions *************************/
+
+/* free */
+
+static void free_proxy_seq(Sequence *seq)
+{
+  if (seq->strip && seq->strip->proxy && seq->strip->proxy->anim) {
+    IMB_free_anim(seq->strip->proxy->anim);
+    seq->strip->proxy->anim = NULL;
+  }
+}
+
+static void seq_free_strip(Strip *strip)
+{
+  strip->us--;
+  if (strip->us > 0) {
+    return;
+  }
+  if (strip->us < 0) {
+    printf("error: negative users in strip\n");
+    return;
+  }
+
+  if (strip->stripdata) {
+    MEM_freeN(strip->stripdata);
+  }
+
+  if (strip->proxy) {
+    if (strip->proxy->anim) {
+      IMB_free_anim(strip->proxy->anim);
+    }
+
+    MEM_freeN(strip->proxy);
+  }
+  if (strip->crop) {
+    MEM_freeN(strip->crop);
+  }
+  if (strip->transform) {
+    MEM_freeN(strip->transform);
+  }
+
+  MEM_freeN(strip);
+}
+
+/* only give option to skip cache locally (static func) */
+static void BKE_sequence_free_ex(Scene *scene,
+                                 Sequence *seq,
+                                 const bool do_cache,
+                                 const bool do_id_user,
+                                 const bool do_clean_animdata)
+{
+  if (seq->strip) {
+    seq_free_strip(seq->strip);
+  }
+
+  BKE_sequence_free_anim(seq);
+
+  if (seq->type & SEQ_TYPE_EFFECT) {
+    struct SeqEffectHandle sh = BKE_sequence_get_effect(seq);
+    sh.free(seq, do_id_user);
+  }
+
+  if (seq->sound && do_id_user) {
+    id_us_min(((ID *)seq->sound));
+  }
+
+  if (seq->stereo3d_format) {
+    MEM_freeN(seq->stereo3d_format);
+  }
+
+  /* clipboard has no scene and will never have a sound handle or be active
+   * same goes to sequences copy for proxy rebuild job
+   */
+  if (scene) {
+    Editing *ed = scene->ed;
+
+    if (ed->act_seq == seq) {
+      ed->act_seq = NULL;
+    }
+
+    if (seq->scene_sound && ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SCENE)) {
+      BKE_sound_remove_scene_sound(scene, seq->scene_sound);
+    }
+
+    /* XXX This must not be done in BKE code. */
+    if (do_clean_animdata) {
+      seq_free_animdata(scene, seq);
+    }
+  }
+
+  if (seq->prop) {
+    IDP_FreePropertyContent_ex(seq->prop, do_id_user);
+    MEM_freeN(seq->prop);
+  }
+
+  /* free modifiers */
+  BKE_sequence_modifier_clear(seq);
+
+  /* free cached data used by this strip,
+   * also invalidate cache for all dependent sequences
+   *
+   * be _very_ careful here, invalidating cache loops over the scene sequences and
+   * assumes the listbase is valid for all strips,
+   * this may not be the case if lists are being freed.
+   * this is optional BKE_sequence_invalidate_cache
+   */
+  if (do_cache) {
+    if (scene) {
+      BKE_sequence_invalidate_cache_raw(scene, seq);
+    }
+  }
+
+  MEM_freeN(seq);
+}
+
+void BKE_sequence_free(Scene *scene, Sequence *seq, const bool do_clean_animdata)
+{
+  BKE_sequence_free_ex(scene, seq, true, true, do_clean_animdata);
+}
+
+/* Function to free imbuf and anim data on changes */
+void BKE_sequence_free_anim(Sequence *seq)
+{
+  while (seq->anims.last) {
+    StripAnim *sanim = seq->anims.last;
+
+    if (sanim->anim) {
+      IMB_free_anim(sanim->anim);
+      sanim->anim = NULL;
+    }
+
+    BLI_freelinkN(&seq->anims, sanim);
+  }
+  BLI_listbase_clear(&seq->anims);
+}
+
+/* cache must be freed before calling this function
+ * since it leaves the seqbase in an invalid state */
+static void seq_free_sequence_recurse(Scene *scene, Sequence *seq, const bool do_id_user)
+{
+  Sequence *iseq, *iseq_next;
+
+  for (iseq = seq->seqbase.first; iseq; iseq = iseq_next) {
+    iseq_next = iseq->next;
+    seq_free_sequence_recurse(scene, iseq, do_id_user);
+  }
+
+  BKE_sequence_free_ex(scene, seq, false, do_id_user, true);
+}
+
+Editing *BKE_sequencer_editing_get(Scene *scene, bool alloc)
+{
+  if (alloc) {
+    BKE_sequencer_editing_ensure(scene);
+  }
+  return scene->ed;
+}
+
+void BKE_sequencer_free_clipboard(void)
+{
+  Sequence *seq, *nseq;
+
+  BKE_sequencer_base_clipboard_pointers_free(&seqbase_clipboard);
+
+  for (seq = seqbase_clipboard.first; seq; seq = nseq) {
+    nseq = seq->next;
+    seq_free_sequence_recurse(NULL, seq, false);
+  }
+  BLI_listbase_clear(&seqbase_clipboard);
+}
+
+/* -------------------------------------------------------------------- */
+/* Manage pointers in the clipboard.
+ * note that these pointers should _never_ be access in the sequencer,
+ * they are only for storage while in the clipboard
+ * notice 'newid' is used for temp pointer storage here, validate on access (this is safe usage,
+ * since those data-blocks are fully out of Main lists).
+ */
+#define ID_PT (*id_pt)
+static void seqclipboard_ptr_free(Main *UNUSED(bmain), ID **id_pt)
+{
+  if (ID_PT) {
+    BLI_assert(ID_PT->newid != NULL);
+    MEM_freeN(ID_PT);
+    ID_PT = NULL;
+  }
+}
+static void seqclipboard_ptr_store(Main *UNUSED(bmain), ID **id_pt)
+{
+  if (ID_PT) {
+    ID *id_prev = ID_PT;
+    ID_PT = MEM_dupallocN(ID_PT);
+    ID_PT->newid = id_prev;
+  }
+}
+static void seqclipboard_ptr_restore(Main *bmain, ID **id_pt)
+{
+  if (ID_PT) {
+    const ListBase *lb = which_libbase(bmain, GS(ID_PT->name));
+    void *id_restore;
+
+    BLI_assert(ID_PT->newid != NULL);
+    if (BLI_findindex(lb, (ID_PT)->newid) != -1) {
+      /* the pointer is still valid */
+      id_restore = (ID_PT)->newid;
+    }
+    else {
+      /* the pointer of the same name still exists  */
+      id_restore = BLI_findstring(lb, (ID_PT)->name + 2, offsetof(ID, name) + 2);
+    }
+
+    if (id_restore == NULL) {
+      /* check for a data with the same filename */
+      switch (GS(ID_PT->name)) {
+        case ID_SO: {
+          id_restore = BLI_findstring(lb, ((bSound *)ID_PT)->filepath, offsetof(bSound, filepath));
+          if (id_restore == NULL) {
+            id_restore = BKE_sound_new_file(bmain, ((bSound *)ID_PT)->filepath);
+            (ID_PT)->newid = id_restore; /* reuse next time */
+          }
+          break;
+        }
+        case ID_MC: {
+          id_restore = BLI_findstring(
+              lb, ((MovieClip *)ID_PT)->filepath, offsetof(MovieClip, filepath));
+          if (id_restore == NULL) {
+            id_restore = BKE_movieclip_file_add(bmain, ((MovieClip *)ID_PT)->filepath);
+            (ID_PT)->newid = id_restore; /* reuse next time */
+          }
+          break;
+        }
+        default:
+          break;
+      }
+    }
+
+    /* Replace with pointer to actual data-block. */
+    seqclipboard_ptr_free(bmain, id_pt);
+    ID_PT = id_restore;
+  }
+}
+#undef ID_PT
+
+static void sequence_clipboard_pointers(Main *bmain,
+                                        Sequence *seq,
+                                        void (*callback)(Main *, ID **))
+{
+  callback(bmain, (ID **)&seq->scene);
+  callback(bmain, (ID **)&seq->scene_camera);
+  callback(bmain, (ID **)&seq->clip);
+  callback(bmain, (ID **)&seq->mask);
+  callback(bmain, (ID **)&seq->sound);
+
+  if (seq->type == SEQ_TYPE_TEXT && seq->effectdata) {
+    TextVars *text_data = seq->effectdata;
+    callback(bmain, (ID **)&text_data->text_font);
+  }
+}
+
+/* recursive versions of functions above */
+void BKE_sequencer_base_clipboard_pointers_free(ListBase *seqbase)
+{
+  Sequence *seq;
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    sequence_clipboard_pointers(NULL, seq, seqclipboard_ptr_free);
+    BKE_sequencer_base_clipboard_pointers_free(&seq->seqbase);
+  }
+}
+void BKE_sequencer_base_clipboard_pointers_store(Main *bmain, ListBase *seqbase)
+{
+  Sequence *seq;
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    sequence_clipboard_pointers(bmain, seq, seqclipboard_ptr_store);
+    BKE_sequencer_base_clipboard_pointers_store(bmain, &seq->seqbase);
+  }
+}
+void BKE_sequencer_base_clipboard_pointers_restore(ListBase *seqbase, Main *bmain)
+{
+  Sequence *seq;
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    sequence_clipboard_pointers(bmain, seq, seqclipboard_ptr_restore);
+    BKE_sequencer_base_clipboard_pointers_restore(&seq->seqbase, bmain);
+  }
+}
+
+/* end clipboard pointer mess */
+
+Editing *BKE_sequencer_editing_ensure(Scene *scene)
+{
+  if (scene->ed == NULL) {
+    Editing *ed;
+
+    ed = scene->ed = MEM_callocN(sizeof(Editing), "addseq");
+    ed->seqbasep = &ed->seqbase;
+    ed->cache = NULL;
+    ed->cache_flag = SEQ_CACHE_STORE_FINAL_OUT;
+    ed->cache_flag |= SEQ_CACHE_VIEW_FINAL_OUT;
+    ed->cache_flag |= SEQ_CACHE_VIEW_ENABLE;
+    ed->recycle_max_cost = 10.0f;
+  }
+
+  return scene->ed;
+}
+
+void BKE_sequencer_editing_free(Scene *scene, const bool do_id_user)
+{
+  Editing *ed = scene->ed;
+  Sequence *seq;
+
+  if (ed == NULL) {
+    return;
+  }
+
+  BKE_sequencer_prefetch_free(scene);
+  BKE_sequencer_cache_destruct(scene);
+
+  SEQ_ALL_BEGIN (ed, seq) {
+    /* handle cache freeing above */
+    BKE_sequence_free_ex(scene, seq, false, do_id_user, false);
+  }
+  SEQ_ALL_END;
+
+  BLI_freelistN(&ed->metastack);
+  MEM_freeN(ed);
+
+  scene->ed = NULL;
+}
+
+/*********************** Sequencer color space functions  *************************/
+
+static void sequencer_imbuf_assign_spaces(Scene *scene, ImBuf *ibuf)
+{
+#if 0
+  /* Bute buffer is supposed to be in sequencer working space already. */
+  if (ibuf->rect != NULL) {
+    IMB_colormanagement_assign_rect_colorspace(ibuf, scene->sequencer_colorspace_settings.name);
+  }
+#endif
+  if (ibuf->rect_float != NULL) {
+    IMB_colormanagement_assign_float_colorspace(ibuf, scene->sequencer_colorspace_settings.name);
+  }
+}
+
+void BKE_sequencer_imbuf_to_sequencer_space(Scene *scene, ImBuf *ibuf, bool make_float)
+{
+  /* Early output check: if both buffers are NULL we have nothing to convert. */
+  if (ibuf->rect_float == NULL && ibuf->rect == NULL) {
+    return;
+  }
+  /* Get common conversion settings. */
+  const char *to_colorspace = scene->sequencer_colorspace_settings.name;
+  /* Perform actual conversion logic. */
+  if (ibuf->rect_float == NULL) {
+    /* We are not requested to give float buffer and byte buffer is already
+     * in thee required colorspace. Can skip doing anything here.
+     */
+    const char *from_colorspace = IMB_colormanagement_get_rect_colorspace(ibuf);
+    if (!make_float && STREQ(from_colorspace, to_colorspace)) {
+      return;
+    }
+    if (false) {
+      /* The idea here is to provide as fast playback as possible and
+       * enforcing float buffer here (a) uses more cache memory (b) might
+       * make some other effects slower to apply.
+       *
+       * However, this might also have negative effect by adding weird
+       * artifacts which will then not happen in final render.
+       */
+      IMB_colormanagement_transform_byte_threaded((unsigned char *)ibuf->rect,
+                                                  ibuf->x,
+                                                  ibuf->y,
+                                                  ibuf->channels,
+                                                  from_colorspace,
+                                                  to_colorspace);
+    }
+    else {
+      /* We perform conversion to a float buffer so we don't worry about
+       * precision loss.
+       */
+      imb_addrectfloatImBuf(ibuf);
+      IMB_colormanagement_transform_from_byte_threaded(ibuf->rect_float,
+                                                       (unsigned char *)ibuf->rect,
+                                                       ibuf->x,
+                                                       ibuf->y,
+                                                       ibuf->channels,
+                                                       from_colorspace,
+                                                       to_colorspace);
+      /* We don't need byte buffer anymore. */
+      imb_freerectImBuf(ibuf);
+    }
+  }
+  else {
+    const char *from_colorspace = IMB_colormanagement_get_float_colorspace(ibuf);
+    /* Unknown input color space, can't perform conversion. */
+    if (from_colorspace == NULL || from_colorspace[0] == '\0') {
+      return;
+    }
+    /* We don't want both byte and float buffers around: they'll either run
+     * out of sync or conversion of byte buffer will loose precision in there.
+     */
+    if (ibuf->rect != NULL) {
+      imb_freerectImBuf(ibuf);
+    }
+    IMB_colormanagement_transform_threaded(
+        ibuf->rect_float, ibuf->x, ibuf->y, ibuf->channels, from_colorspace, to_colorspace, true);
+  }
+  sequencer_imbuf_assign_spaces(scene, ibuf);
+}
+
+void BKE_sequencer_imbuf_from_sequencer_space(Scene *scene, ImBuf *ibuf)
+{
+  const char *from_colorspace = scene->sequencer_colorspace_settings.name;
+  const char *to_colorspace = IMB_colormanagement_role_colorspace_name_get(
+      COLOR_ROLE_SCENE_LINEAR);
+
+  if (!ibuf->rect_float) {
+    return;
+  }
+
+  if (to_colorspace && to_colorspace[0] != '\0') {
+    IMB_colormanagement_transform_threaded(
+        ibuf->rect_float, ibuf->x, ibuf->y, ibuf->channels, from_colorspace, to_colorspace, true);
+    IMB_colormanagement_assign_float_colorspace(ibuf, to_colorspace);
+  }
+}
+
+void BKE_sequencer_pixel_from_sequencer_space_v4(struct Scene *scene, float pixel[4])
+{
+  const char *from_colorspace = scene->sequencer_colorspace_settings.name;
+  const char *to_colorspace = IMB_colormanagement_role_colorspace_name_get(
+      COLOR_ROLE_SCENE_LINEAR);
+
+  if (to_colorspace && to_colorspace[0] != '\0') {
+    IMB_colormanagement_transform_v4(pixel, from_colorspace, to_colorspace);
+  }
+  else {
+    /* if no color management enables fallback to legacy conversion */
+    srgb_to_linearrgb_v4(pixel, pixel);
+  }
+}
+
+/*********************** sequencer pipeline functions *************************/
+
+void BKE_sequencer_new_render_data(Main *bmain,
+                                   struct Depsgraph *depsgraph,
+                                   Scene *scene,
+                                   int rectx,
+                                   int recty,
+                                   int preview_render_size,
+                                   int for_render,
+                                   SeqRenderData *r_context)
+{
+  r_context->bmain = bmain;
+  r_context->depsgraph = depsgraph;
+  r_context->scene = scene;
+  r_context->rectx = rectx;
+  r_context->recty = recty;
+  r_context->preview_render_size = preview_render_size;
+  r_context->for_render = for_render;
+  r_context->motion_blur_samples = 0;
+  r_context->motion_blur_shutter = 0;
+  r_context->skip_cache = false;
+  r_context->is_proxy_render = false;
+  r_context->view_id = 0;
+  r_context->gpu_offscreen = NULL;
+  r_context->task_id = SEQ_TASK_MAIN_RENDER;
+  r_context->is_prefetch_render = false;
+}
+
+/* ************************* iterator ************************** */
+/* *************** (replaces old WHILE_SEQ) ********************* */
+/* **************** use now SEQ_ALL_BEGIN () SEQ_ALL_END ***************** */
+
+/* sequence strip iterator:
+ * - builds a full array, recursively into meta strips
+ */
+
+static void seq_count(ListBase *seqbase, int *tot)
+{
+  Sequence *seq;
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    (*tot)++;
+
+    if (seq->seqbase.first) {
+      seq_count(&seq->seqbase, tot);
+    }
+  }
+}
+
+static void seq_build_array(ListBase *seqbase, Sequence ***array, int depth)
+{
+  Sequence *seq;
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    seq->depth = depth;
+
+    if (seq->seqbase.first) {
+      seq_build_array(&seq->seqbase, array, depth + 1);
+    }
+
+    **array = seq;
+    (*array)++;
+  }
+}
+
+static void seq_array(Editing *ed,
+                      Sequence ***seqarray,
+                      int *tot,
+                      const bool use_current_sequences)
+{
+  Sequence **array;
+
+  *seqarray = NULL;
+  *tot = 0;
+
+  if (ed == NULL) {
+    return;
+  }
+
+  if (use_current_sequences) {
+    seq_count(ed->seqbasep, tot);
+  }
+  else {
+    seq_count(&ed->seqbase, tot);
+  }
+
+  if (*tot == 0) {
+    return;
+  }
+
+  *seqarray = array = MEM_mallocN(sizeof(Sequence *) * (*tot), "SeqArray");
+  if (use_current_sequences) {
+    seq_build_array(ed->seqbasep, &array, 0);
+  }
+  else {
+    seq_build_array(&ed->seqbase, &array, 0);
+  }
+}
+
+void BKE_sequence_iterator_begin(Editing *ed, SeqIterator *iter, const bool use_current_sequences)
+{
+  memset(iter, 0, sizeof(*iter));
+  seq_array(ed, &iter->array, &iter->tot, use_current_sequences);
+
+  if (iter->tot) {
+    iter->cur = 0;
+    iter->seq = iter->array[iter->cur];
+    iter->valid = 1;
+  }
+}
+
+void BKE_sequence_iterator_next(SeqIterator *iter)
+{
+  if (++iter->cur < iter->tot) {
+    iter->seq = iter->array[iter->cur];
+  }
+  else {
+    iter->valid = 0;
+  }
+}
+
+void BKE_sequence_iterator_end(SeqIterator *iter)
+{
+  if (iter->array) {
+    MEM_freeN(iter->array);
+  }
+
+  iter->valid = 0;
+}
+
+static int metaseq_start(Sequence *metaseq)
+{
+  return metaseq->start + metaseq->startofs;
+}
+
+static int metaseq_end(Sequence *metaseq)
+{
+  return metaseq->start + metaseq->len - metaseq->endofs;
+}
+
+static void seq_update_sound_bounds_recursive_impl(Scene *scene,
+                                                   Sequence *metaseq,
+                                                   int start,
+                                                   int end)
+{
+  Sequence *seq;
+
+  /* for sound we go over full meta tree to update bounds of the sound strips,
+   * since sound is played outside of evaluating the imbufs, */
+  for (seq = metaseq->seqbase.first; seq; seq = seq->next) {
+    if (seq->type == SEQ_TYPE_META) {
+      seq_update_sound_bounds_recursive_impl(
+          scene, seq, max_ii(start, metaseq_start(seq)), min_ii(end, metaseq_end(seq)));
+    }
+    else if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SCENE)) {
+      if (seq->scene_sound) {
+        int startofs = seq->startofs;
+        int endofs = seq->endofs;
+        if (seq->startofs + seq->start < start) {
+          startofs = start - seq->start;
+        }
+
+        if (seq->start + seq->len - seq->endofs > end) {
+          endofs = seq->start + seq->len - end;
+        }
+
+        BKE_sound_move_scene_sound(scene,
+                                   seq->scene_sound,
+                                   seq->start + startofs,
+                                   seq->start + seq->len - endofs,
+                                   startofs + seq->anim_startofs);
+      }
+    }
+  }
+}
+
+static void seq_update_sound_bounds_recursive(Scene *scene, Sequence *metaseq)
+{
+  seq_update_sound_bounds_recursive_impl(
+      scene, metaseq, metaseq_start(metaseq), metaseq_end(metaseq));
+}
+
+void BKE_sequence_calc_disp(Scene *scene, Sequence *seq)
+{
+  if (seq->startofs && seq->startstill) {
+    seq->startstill = 0;
+  }
+  if (seq->endofs && seq->endstill) {
+    seq->endstill = 0;
+  }
+
+  seq->startdisp = seq->start + seq->startofs - seq->startstill;
+  seq->enddisp = seq->start + seq->len - seq->endofs + seq->endstill;
+
+  if (seq->type == SEQ_TYPE_META) {
+    seq_update_sound_bounds_recursive(scene, seq);
+  }
+}
+
+void BKE_sequence_calc(Scene *scene, Sequence *seq)
+{
+  Sequence *seqm;
+  int min, max;
+
+  /* check all metas recursively */
+  seqm = seq->seqbase.first;
+  while (seqm) {
+    if (seqm->seqbase.first) {
+      BKE_sequence_calc(scene, seqm);
+    }
+    seqm = seqm->next;
+  }
+
+  /* effects and meta: automatic start and end */
+  if (seq->type & SEQ_TYPE_EFFECT) {
+    if (seq->seq1) {
+      seq->startofs = seq->endofs = seq->startstill = seq->endstill = 0;
+      if (seq->seq3) {
+        seq->start = seq->startdisp = max_iii(
+            seq->seq1->startdisp, seq->seq2->startdisp, seq->seq3->startdisp);
+        seq->enddisp = min_iii(seq->seq1->enddisp, seq->seq2->enddisp, seq->seq3->enddisp);
+      }
+      else if (seq->seq2) {
+        seq->start = seq->startdisp = max_ii(seq->seq1->startdisp, seq->seq2->startdisp);
+        seq->enddisp = min_ii(seq->seq1->enddisp, seq->seq2->enddisp);
+      }
+      else {
+        seq->start = seq->startdisp = seq->seq1->startdisp;
+        seq->enddisp = seq->seq1->enddisp;
+      }
+      /* we cant help if strips don't overlap, it wont give useful results.
+       * but at least ensure 'len' is never negative which causes bad bugs elsewhere. */
+      if (seq->enddisp < seq->startdisp) {
+        /* simple start/end swap */
+        seq->start = seq->enddisp;
+        seq->enddisp = seq->startdisp;
+        seq->startdisp = seq->start;
+        seq->flag |= SEQ_INVALID_EFFECT;
+      }
+      else {
+        seq->flag &= ~SEQ_INVALID_EFFECT;
+      }
+
+      seq->len = seq->enddisp - seq->startdisp;
+    }
+    else {
+      BKE_sequence_calc_disp(scene, seq);
+    }
+  }
+  else {
+    if (seq->type == SEQ_TYPE_META) {
+      seqm = seq->seqbase.first;
+      if (seqm) {
+        min = MAXFRAME * 2;
+        max = -MAXFRAME * 2;
+        while (seqm) {
+          if (seqm->startdisp < min) {
+            min = seqm->startdisp;
+          }
+          if (seqm->enddisp > max) {
+            max = seqm->enddisp;
+          }
+          seqm = seqm->next;
+        }
+        seq->start = min + seq->anim_startofs;
+        seq->len = max - min;
+        seq->len -= seq->anim_startofs;
+        seq->len -= seq->anim_endofs;
+      }
+      seq_update_sound_bounds_recursive(scene, seq);
+    }
+    BKE_sequence_calc_disp(scene, seq);
+  }
+}
+
+static void seq_multiview_name(Scene *scene,
+                               const int view_id,
+                               const char *prefix,
+                               const char *ext,
+                               char *r_path,
+                               size_t r_size)
+{
+  const char *suffix = BKE_scene_multiview_view_id_suffix_get(&scene->r, view_id);
+  BLI_assert(ext != NULL && suffix != NULL && prefix != NULL);
+  BLI_snprintf(r_path, r_size, "%s%s%s", prefix, suffix, ext);
+}
+
+/* note: caller should run BKE_sequence_calc(scene, seq) after */
+void BKE_sequence_reload_new_file(Main *bmain, Scene *scene, Sequence *seq, const bool lock_range)
+{
+  char path[FILE_MAX];
+  int prev_startdisp = 0, prev_enddisp = 0;
+  /* note: don't rename the strip, will break animation curves */
+
+  if (ELEM(seq->type,
+           SEQ_TYPE_MOVIE,
+           SEQ_TYPE_IMAGE,
+           SEQ_TYPE_SOUND_RAM,
+           SEQ_TYPE_SCENE,
+           SEQ_TYPE_META,
+           SEQ_TYPE_MOVIECLIP,
+           SEQ_TYPE_MASK) == 0) {
+    return;
+  }
+
+  if (lock_range) {
+    /* keep so we don't have to move the actual start and end points (only the data) */
+    BKE_sequence_calc_disp(scene, seq);
+    prev_startdisp = seq->startdisp;
+    prev_enddisp = seq->enddisp;
+  }
+
+  switch (seq->type) {
+    case SEQ_TYPE_IMAGE: {
+      /* Hack? */
+      size_t olen = MEM_allocN_len(seq->strip->stripdata) / sizeof(StripElem);
+
+      seq->len = olen;
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+      break;
+    }
+    case SEQ_TYPE_MOVIE: {
+      StripAnim *sanim;
+      bool is_multiview_loaded = false;
+      const bool is_multiview = (seq->flag & SEQ_USE_VIEWS) != 0 &&
+                                (scene->r.scemode & R_MULTIVIEW) != 0;
+
+      BLI_join_dirfile(path, sizeof(path), seq->strip->dir, seq->strip->stripdata->name);
+      BLI_path_abs(path, BKE_main_blendfile_path_from_global());
+
+      BKE_sequence_free_anim(seq);
+
+      if (is_multiview && (seq->views_format == R_IMF_VIEWS_INDIVIDUAL)) {
+        char prefix[FILE_MAX];
+        const char *ext = NULL;
+        const int totfiles = seq_num_files(scene, seq->views_format, true);
+        int i = 0;
+
+        BKE_scene_multiview_view_prefix_get(scene, path, prefix, &ext);
+
+        if (prefix[0] != '\0') {
+          for (i = 0; i < totfiles; i++) {
+            struct anim *anim;
+            char str[FILE_MAX];
+
+            seq_multiview_name(scene, i, prefix, ext, str, FILE_MAX);
+            anim = openanim(str,
+                            IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                            seq->streamindex,
+                            seq->strip->colorspace_settings.name);
+
+            if (anim) {
+              seq_anim_add_suffix(scene, anim, i);
+              sanim = MEM_mallocN(sizeof(StripAnim), "Strip Anim");
+              BLI_addtail(&seq->anims, sanim);
+              sanim->anim = anim;
+            }
+          }
+          is_multiview_loaded = true;
+        }
+      }
+
+      if (is_multiview_loaded == false) {
+        struct anim *anim;
+        anim = openanim(path,
+                        IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                        seq->streamindex,
+                        seq->strip->colorspace_settings.name);
+        if (anim) {
+          sanim = MEM_mallocN(sizeof(StripAnim), "Strip Anim");
+          BLI_addtail(&seq->anims, sanim);
+          sanim->anim = anim;
+        }
+      }
+
+      /* use the first video as reference for everything */
+      sanim = seq->anims.first;
+
+      if ((!sanim) || (!sanim->anim)) {
+        return;
+      }
+
+      IMB_anim_load_metadata(sanim->anim);
+
+      seq->len = IMB_anim_get_duration(
+          sanim->anim, seq->strip->proxy ? seq->strip->proxy->tc : IMB_TC_RECORD_RUN);
+
+      seq->anim_preseek = IMB_anim_get_preseek(sanim->anim);
+
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+      break;
+    }
+    case SEQ_TYPE_MOVIECLIP:
+      if (seq->clip == NULL) {
+        return;
+      }
+
+      seq->len = BKE_movieclip_get_duration(seq->clip);
+
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+      break;
+    case SEQ_TYPE_MASK:
+      if (seq->mask == NULL) {
+        return;
+      }
+      seq->len = BKE_mask_get_duration(seq->mask);
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+      break;
+    case SEQ_TYPE_SOUND_RAM:
+#ifdef WITH_AUDASPACE
+      if (!seq->sound) {
+        return;
+      }
+      seq->len = ceil((double)BKE_sound_get_length(bmain, seq->sound) * FPS);
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+#else
+      UNUSED_VARS(bmain);
+      return;
+#endif
+      break;
+    case SEQ_TYPE_SCENE: {
+      seq->len = (seq->scene) ? seq->scene->r.efra - seq->scene->r.sfra + 1 : 0;
+      seq->len -= seq->anim_startofs;
+      seq->len -= seq->anim_endofs;
+      if (seq->len < 0) {
+        seq->len = 0;
+      }
+      break;
+    }
+  }
+
+  free_proxy_seq(seq);
+
+  if (lock_range) {
+    BKE_sequence_tx_set_final_left(seq, prev_startdisp);
+    BKE_sequence_tx_set_final_right(seq, prev_enddisp);
+    BKE_sequence_single_fix(seq);
+  }
+
+  BKE_sequence_calc(scene, seq);
+}
+
+void BKE_sequence_movie_reload_if_needed(struct Main *bmain,
+                                         struct Scene *scene,
+                                         struct Sequence *seq,
+                                         bool *r_was_reloaded,
+                                         bool *r_can_produce_frames)
+{
+  BLI_assert(seq->type == SEQ_TYPE_MOVIE ||
+             !"This function is only implemented for movie strips.");
+
+  bool must_reload = false;
+
+  /* The Sequence struct allows for multiple anim structs to be associated with one strip. This
+   * function will return true only if there is at least one 'anim' AND all anims can produce
+   * frames. */
+
+  if (BLI_listbase_is_empty(&seq->anims)) {
+    /* No anim present, so reloading is always necessary. */
+    must_reload = true;
+  }
+  else {
+    LISTBASE_FOREACH (StripAnim *, sanim, &seq->anims) {
+      if (!IMB_anim_can_produce_frames(sanim->anim)) {
+        /* Anim cannot produce frames, try reloading. */
+        must_reload = true;
+        break;
+      }
+    };
+  }
+
+  if (!must_reload) {
+    /* There are one or more anims, and all can produce frames. */
+    *r_was_reloaded = false;
+    *r_can_produce_frames = true;
+    return;
+  }
+
+  BKE_sequence_reload_new_file(bmain, scene, seq, true);
+  *r_was_reloaded = true;
+
+  if (BLI_listbase_is_empty(&seq->anims)) {
+    /* No anims present after reloading => no frames can be produced. */
+    *r_can_produce_frames = false;
+    return;
+  }
+
+  /* Check if there are still anims that cannot produce frames. */
+  LISTBASE_FOREACH (StripAnim *, sanim, &seq->anims) {
+    if (!IMB_anim_can_produce_frames(sanim->anim)) {
+      /* There still is an anim that cannot produce frames. */
+      *r_can_produce_frames = false;
+      return;
+    }
+  };
+
+  /* There are one or more anims, and all can produce frames. */
+  *r_can_produce_frames = true;
+}
+
+void BKE_sequencer_sort(Scene *scene)
+{
+  /* all strips together per kind, and in order of y location ("machine") */
+  ListBase seqbase, effbase;
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  Sequence *seq, *seqt;
+
+  if (ed == NULL) {
+    return;
+  }
+
+  BLI_listbase_clear(&seqbase);
+  BLI_listbase_clear(&effbase);
+
+  while ((seq = BLI_pophead(ed->seqbasep))) {
+
+    if (seq->type & SEQ_TYPE_EFFECT) {
+      seqt = effbase.first;
+      while (seqt) {
+        if (seqt->machine >= seq->machine) {
+          BLI_insertlinkbefore(&effbase, seqt, seq);
+          break;
+        }
+        seqt = seqt->next;
+      }
+      if (seqt == NULL) {
+        BLI_addtail(&effbase, seq);
+      }
+    }
+    else {
+      seqt = seqbase.first;
+      while (seqt) {
+        if (seqt->machine >= seq->machine) {
+          BLI_insertlinkbefore(&seqbase, seqt, seq);
+          break;
+        }
+        seqt = seqt->next;
+      }
+      if (seqt == NULL) {
+        BLI_addtail(&seqbase, seq);
+      }
+    }
+  }
+
+  BLI_movelisttolist(&seqbase, &effbase);
+  *(ed->seqbasep) = seqbase;
+}
+
+/** Comparison function suitable to be used with BLI_listbase_sort()... */
+int BKE_sequencer_cmp_time_startdisp(const void *a, const void *b)
+{
+  const Sequence *seq_a = a;
+  const Sequence *seq_b = b;
+
+  return (seq_a->startdisp > seq_b->startdisp);
+}
+
+static int clear_scene_in_allseqs_fn(Sequence *seq, void *arg_pt)
+{
+  if (seq->scene == (Scene *)arg_pt) {
+    seq->scene = NULL;
+  }
+  return 1;
+}
+
+void BKE_sequencer_clear_scene_in_allseqs(Main *bmain, Scene *scene)
+{
+  Scene *scene_iter;
+
+  /* when a scene is deleted: test all seqs */
+  for (scene_iter = bmain->scenes.first; scene_iter; scene_iter = scene_iter->id.next) {
+    if (scene_iter != scene && scene_iter->ed) {
+      BKE_sequencer_base_recursive_apply(
+          &scene_iter->ed->seqbase, clear_scene_in_allseqs_fn, scene);
+    }
+  }
+}
+
+typedef struct SeqUniqueInfo {
+  Sequence *seq;
+  char name_src[SEQ_NAME_MAXSTR];
+  char name_dest[SEQ_NAME_MAXSTR];
+  int count;
+  int match;
+} SeqUniqueInfo;
+
+static void seqbase_unique_name(ListBase *seqbasep, SeqUniqueInfo *sui)
+{
+  Sequence *seq;
+  for (seq = seqbasep->first; seq; seq = seq->next) {
+    if ((sui->seq != seq) && STREQ(sui->name_dest, seq->name + 2)) {
+      /* SEQ_NAME_MAXSTR -4 for the number, -1 for \0, - 2 for r_prefix */
+      BLI_snprintf(sui->name_dest,
+                   sizeof(sui->name_dest),
+                   "%.*s.%03d",
+                   SEQ_NAME_MAXSTR - 4 - 1 - 2,
+                   sui->name_src,
+                   sui->count++);
+      sui->match = 1; /* be sure to re-scan */
+    }
+  }
+}
+
+static int seqbase_unique_name_recursive_fn(Sequence *seq, void *arg_pt)
+{
+  if (seq->seqbase.first) {
+    seqbase_unique_name(&seq->seqbase, (SeqUniqueInfo *)arg_pt);
+  }
+  return 1;
+}
+
+void BKE_sequence_base_unique_name_recursive(ListBase *seqbasep, Sequence *seq)
+{
+  SeqUniqueInfo sui;
+  char *dot;
+  sui.seq = seq;
+  BLI_strncpy(sui.name_src, seq->name + 2, sizeof(sui.name_src));
+  BLI_strncpy(sui.name_dest, seq->name + 2, sizeof(sui.name_dest));
+
+  sui.count = 1;
+  sui.match = 1; /* assume the worst to start the loop */
+
+  /* Strip off the suffix */
+  if ((dot = strrchr(sui.name_src, '.'))) {
+    *dot = '\0';
+    dot++;
+
+    if (*dot) {
+      sui.count = atoi(dot) + 1;
+    }
+  }
+
+  while (sui.match) {
+    sui.match = 0;
+    seqbase_unique_name(seqbasep, &sui);
+    BKE_sequencer_base_recursive_apply(seqbasep, seqbase_unique_name_recursive_fn, &sui);
+  }
+
+  BLI_strncpy(seq->name + 2, sui.name_dest, sizeof(seq->name) - 2);
+}
+
+static const char *give_seqname_by_type(int type)
+{
+  switch (type) {
+    case SEQ_TYPE_META:
+      return "Meta";
+    case SEQ_TYPE_IMAGE:
+      return "Image";
+    case SEQ_TYPE_SCENE:
+      return "Scene";
+    case SEQ_TYPE_MOVIE:
+      return "Movie";
+    case SEQ_TYPE_MOVIECLIP:
+      return "Clip";
+    case SEQ_TYPE_MASK:
+      return "Mask";
+    case SEQ_TYPE_SOUND_RAM:
+      return "Audio";
+    case SEQ_TYPE_CROSS:
+      return "Cross";
+    case SEQ_TYPE_GAMCROSS:
+      return "Gamma Cross";
+    case SEQ_TYPE_ADD:
+      return "Add";
+    case SEQ_TYPE_SUB:
+      return "Sub";
+    case SEQ_TYPE_MUL:
+      return "Mul";
+    case SEQ_TYPE_ALPHAOVER:
+      return "Alpha Over";
+    case SEQ_TYPE_ALPHAUNDER:
+      return "Alpha Under";
+    case SEQ_TYPE_OVERDROP:
+      return "Over Drop";
+    case SEQ_TYPE_COLORMIX:
+      return "Color Mix";
+    case SEQ_TYPE_WIPE:
+      return "Wipe";
+    case SEQ_TYPE_GLOW:
+      return "Glow";
+    case SEQ_TYPE_TRANSFORM:
+      return "Transform";
+    case SEQ_TYPE_COLOR:
+      return "Color";
+    case SEQ_TYPE_MULTICAM:
+      return "Multicam";
+    case SEQ_TYPE_ADJUSTMENT:
+      return "Adjustment";
+    case SEQ_TYPE_SPEED:
+      return "Speed";
+    case SEQ_TYPE_GAUSSIAN_BLUR:
+      return "Gaussian Blur";
+    case SEQ_TYPE_TEXT:
+      return "Text";
+    default:
+      return NULL;
+  }
+}
+
+const char *BKE_sequence_give_name(Sequence *seq)
+{
+  const char *name = give_seqname_by_type(seq->type);
+
+  if (!name) {
+    if (!(seq->type & SEQ_TYPE_EFFECT)) {
+      return seq->strip->dir;
+    }
+
+    return "Effect";
+  }
+  return name;
+}
+
+ListBase *BKE_sequence_seqbase_get(Sequence *seq, int *r_offset)
+{
+  ListBase *seqbase = NULL;
+
+  switch (seq->type) {
+    case SEQ_TYPE_META: {
+      seqbase = &seq->seqbase;
+      *r_offset = seq->start;
+      break;
+    }
+    case SEQ_TYPE_SCENE: {
+      if (seq->flag & SEQ_SCENE_STRIPS && seq->scene) {
+        Editing *ed = BKE_sequencer_editing_get(seq->scene, false);
+        if (ed) {
+          seqbase = &ed->seqbase;
+          *r_offset = seq->scene->r.sfra;
+        }
+      }
+      break;
+    }
+  }
+
+  return seqbase;
+}
+
+/*********************** DO THE SEQUENCE *************************/
+
+static void multibuf(ImBuf *ibuf, const float fmul)
+{
+  char *rt;
+  float *rt_float;
+
+  int a;
+
+  rt = (char *)ibuf->rect;
+  rt_float = ibuf->rect_float;
+
+  if (rt) {
+    const int imul = (int)(256.0f * fmul);
+    a = ibuf->x * ibuf->y;
+    while (a--) {
+      rt[0] = min_ii((imul * rt[0]) >> 8, 255);
+      rt[1] = min_ii((imul * rt[1]) >> 8, 255);
+      rt[2] = min_ii((imul * rt[2]) >> 8, 255);
+      rt[3] = min_ii((imul * rt[3]) >> 8, 255);
+
+      rt += 4;
+    }
+  }
+  if (rt_float) {
+    a = ibuf->x * ibuf->y;
+    while (a--) {
+      rt_float[0] *= fmul;
+      rt_float[1] *= fmul;
+      rt_float[2] *= fmul;
+      rt_float[3] *= fmul;
+
+      rt_float += 4;
+    }
+  }
+}
+
+float BKE_sequencer_give_stripelem_index(Sequence *seq, float cfra)
+{
+  float nr;
+  int sta = seq->start;
+  int end = seq->start + seq->len - 1;
+
+  if (seq->type & SEQ_TYPE_EFFECT) {
+    end = seq->enddisp;
+  }
+
+  if (end < sta) {
+    return -1;
+  }
+
+  if (seq->flag & SEQ_REVERSE_FRAMES) {
+    /*reverse frame in this sequence */
+    if (cfra <= sta) {
+      nr = end - sta;
+    }
+    else if (cfra >= end) {
+      nr = 0;
+    }
+    else {
+      nr = end - cfra;
+    }
+  }
+  else {
+    if (cfra <= sta) {
+      nr = 0;
+    }
+    else if (cfra >= end) {
+      nr = end - sta;
+    }
+    else {
+      nr = cfra - sta;
+    }
+  }
+
+  if (seq->strobe < 1.0f) {
+    seq->strobe = 1.0f;
+  }
+
+  if (seq->strobe > 1.0f) {
+    nr -= fmodf((double)nr, (double)seq->strobe);
+  }
+
+  return nr;
+}
+
+StripElem *BKE_sequencer_give_stripelem(Sequence *seq, int cfra)
+{
+  StripElem *se = seq->strip->stripdata;
+
+  if (seq->type == SEQ_TYPE_IMAGE) {
+    /* only IMAGE strips use the whole array, MOVIE strips use only the first element,
+     * all other strips don't use this...
+     */
+
+    int nr = (int)BKE_sequencer_give_stripelem_index(seq, cfra);
+
+    if (nr == -1 || se == NULL) {
+      return NULL;
+    }
+
+    se += nr + seq->anim_startofs;
+  }
+  return se;
+}
+
+static int evaluate_seq_frame_gen(Sequence **seq_arr, ListBase *seqbase, int cfra, int chanshown)
+{
+  /* Use arbitrary sized linked list, the size could be over MAXSEQ. */
+  LinkNodePair effect_inputs = {NULL, NULL};
+  int totseq = 0;
+
+  memset(seq_arr, 0, sizeof(Sequence *) * (MAXSEQ + 1));
+
+  LISTBASE_FOREACH (Sequence *, seq, seqbase) {
+    if ((seq->startdisp <= cfra) && (seq->enddisp > cfra)) {
+      if ((seq->type & SEQ_TYPE_EFFECT) && !(seq->flag & SEQ_MUTE)) {
+
+        if (seq->seq1) {
+          BLI_linklist_append_alloca(&effect_inputs, seq->seq1);
+        }
+
+        if (seq->seq2) {
+          BLI_linklist_append_alloca(&effect_inputs, seq->seq2);
+        }
+
+        if (seq->seq3) {
+          BLI_linklist_append_alloca(&effect_inputs, seq->seq3);
+        }
+      }
+
+      seq_arr[seq->machine] = seq;
+      totseq++;
+    }
+  }
+
+  /* Drop strips which are used for effect inputs, we don't want
+   * them to blend into render stack in any other way than effect
+   * string rendering. */
+  for (LinkNode *seq_item = effect_inputs.list; seq_item; seq_item = seq_item->next) {
+    Sequence *seq = seq_item->link;
+    /* It's possible that effect strip would be placed to the same
+     * 'machine' as it's inputs. We don't want to clear such strips
+     * from the stack. */
+    if (seq_arr[seq->machine] && seq_arr[seq->machine]->type & SEQ_TYPE_EFFECT) {
+      continue;
+    }
+    /* If we're shown a specified channel, then we want to see the strips
+     * which belongs to this machine. */
+    if (chanshown != 0 && chanshown <= seq->machine) {
+      continue;
+    }
+    seq_arr[seq->machine] = NULL;
+  }
+
+  return totseq;
+}
+
+int BKE_sequencer_evaluate_frame(Scene *scene, int cfra)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  Sequence *seq_arr[MAXSEQ + 1];
+
+  if (ed == NULL) {
+    return 0;
+  }
+
+  return evaluate_seq_frame_gen(seq_arr, ed->seqbasep, cfra, 0);
+}
+
+static bool video_seq_is_rendered(Sequence *seq)
+{
+  return (seq && !(seq->flag & SEQ_MUTE) && seq->type != SEQ_TYPE_SOUND_RAM);
+}
+
+int BKE_sequencer_get_shown_sequences(ListBase *seqbasep,
+                                      int cfra,
+                                      int chanshown,
+                                      Sequence **seq_arr_out)
+{
+  Sequence *seq_arr[MAXSEQ + 1];
+  int b = chanshown;
+  int cnt = 0;
+
+  if (b > MAXSEQ) {
+    return 0;
+  }
+
+  if (evaluate_seq_frame_gen(seq_arr, seqbasep, cfra, chanshown)) {
+    if (b == 0) {
+      b = MAXSEQ;
+    }
+    for (; b > 0; b--) {
+      if (video_seq_is_rendered(seq_arr[b])) {
+        break;
+      }
+    }
+  }
+
+  chanshown = b;
+
+  for (; b > 0; b--) {
+    if (video_seq_is_rendered(seq_arr[b])) {
+      if (seq_arr[b]->blend_mode == SEQ_BLEND_REPLACE) {
+        break;
+      }
+    }
+  }
+
+  for (; b <= chanshown && b >= 0; b++) {
+    if (video_seq_is_rendered(seq_arr[b])) {
+      seq_arr_out[cnt++] = seq_arr[b];
+    }
+  }
+
+  return cnt;
+}
+
+/*********************** proxy management *************************/
+
+typedef struct SeqIndexBuildContext {
+  struct IndexBuildContext *index_context;
+
+  int tc_flags;
+  int size_flags;
+  int quality;
+  bool overwrite;
+  int view_id;
+
+  Main *bmain;
+  Depsgraph *depsgraph;
+  Scene *scene;
+  Sequence *seq, *orig_seq;
+} SeqIndexBuildContext;
+
+#define PROXY_MAXFILE (2 * FILE_MAXDIR + FILE_MAXFILE)
+
+static IMB_Proxy_Size seq_rendersize_to_proxysize(int render_size)
+{
+  switch (render_size) {
+    case SEQ_RENDER_SIZE_PROXY_25:
+      return IMB_PROXY_25;
+    case SEQ_RENDER_SIZE_PROXY_50:
+      return IMB_PROXY_50;
+    case SEQ_RENDER_SIZE_PROXY_75:
+      return IMB_PROXY_75;
+    case SEQ_RENDER_SIZE_PROXY_100:
+      return IMB_PROXY_100;
+  }
+  return IMB_PROXY_NONE;
+}
+
+double BKE_sequencer_rendersize_to_scale_factor(int render_size)
+{
+  switch (render_size) {
+    case SEQ_RENDER_SIZE_PROXY_25:
+      return 0.25;
+    case SEQ_RENDER_SIZE_PROXY_50:
+      return 0.50;
+    case SEQ_RENDER_SIZE_PROXY_75:
+      return 0.75;
+  }
+  return 1.0;
+}
+
+/* the number of files will vary according to the stereo format */
+static int seq_num_files(Scene *scene, char views_format, const bool is_multiview)
+{
+  if (!is_multiview) {
+    return 1;
+  }
+  if (views_format == R_IMF_VIEWS_STEREO_3D) {
+    return 1;
+  }
+  /* R_IMF_VIEWS_INDIVIDUAL */
+
+  return BKE_scene_multiview_num_views_get(&scene->r);
+}
+
+static void seq_proxy_index_dir_set(struct anim *anim, const char *base_dir)
+{
+  char dir[FILE_MAX];
+  char fname[FILE_MAXFILE];
+
+  IMB_anim_get_fname(anim, fname, FILE_MAXFILE);
+  BLI_strncpy(dir, base_dir, sizeof(dir));
+  BLI_path_append(dir, sizeof(dir), fname);
+  IMB_anim_set_index_dir(anim, dir);
+}
+
+static void seq_open_anim_file(Scene *scene, Sequence *seq, bool openfile)
+{
+  char dir[FILE_MAX];
+  char name[FILE_MAX];
+  StripProxy *proxy;
+  bool use_proxy;
+  bool is_multiview_loaded = false;
+  Editing *ed = scene->ed;
+  const bool is_multiview = (seq->flag & SEQ_USE_VIEWS) != 0 &&
+                            (scene->r.scemode & R_MULTIVIEW) != 0;
+
+  if ((seq->anims.first != NULL) && (((StripAnim *)seq->anims.first)->anim != NULL)) {
+    return;
+  }
+
+  /* reset all the previously created anims */
+  BKE_sequence_free_anim(seq);
+
+  BLI_join_dirfile(name, sizeof(name), seq->strip->dir, seq->strip->stripdata->name);
+  BLI_path_abs(name, BKE_main_blendfile_path_from_global());
+
+  proxy = seq->strip->proxy;
+
+  use_proxy = proxy && ((proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_DIR) != 0 ||
+                        (ed->proxy_storage == SEQ_EDIT_PROXY_DIR_STORAGE));
+
+  if (use_proxy) {
+    if (ed->proxy_storage == SEQ_EDIT_PROXY_DIR_STORAGE) {
+      if (ed->proxy_dir[0] == 0) {
+        BLI_strncpy(dir, "//BL_proxy", sizeof(dir));
+      }
+      else {
+        BLI_strncpy(dir, ed->proxy_dir, sizeof(dir));
+      }
+    }
+    else {
+      BLI_strncpy(dir, seq->strip->proxy->dir, sizeof(dir));
+    }
+    BLI_path_abs(dir, BKE_main_blendfile_path_from_global());
+  }
+
+  if (is_multiview && seq->views_format == R_IMF_VIEWS_INDIVIDUAL) {
+    int totfiles = seq_num_files(scene, seq->views_format, true);
+    char prefix[FILE_MAX];
+    const char *ext = NULL;
+    int i;
+
+    BKE_scene_multiview_view_prefix_get(scene, name, prefix, &ext);
+
+    if (prefix[0] != '\0') {
+      for (i = 0; i < totfiles; i++) {
+        const char *suffix = BKE_scene_multiview_view_id_suffix_get(&scene->r, i);
+        char str[FILE_MAX];
+        StripAnim *sanim = MEM_mallocN(sizeof(StripAnim), "Strip Anim");
+
+        BLI_addtail(&seq->anims, sanim);
+
+        BLI_snprintf(str, sizeof(str), "%s%s%s", prefix, suffix, ext);
+
+        if (openfile) {
+          sanim->anim = openanim(str,
+                                 IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                                 seq->streamindex,
+                                 seq->strip->colorspace_settings.name);
+        }
+        else {
+          sanim->anim = openanim_noload(str,
+                                        IB_rect |
+                                            ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                                        seq->streamindex,
+                                        seq->strip->colorspace_settings.name);
+        }
+
+        if (sanim->anim) {
+          /* we already have the suffix */
+          IMB_suffix_anim(sanim->anim, suffix);
+        }
+        else {
+          if (openfile) {
+            sanim->anim = openanim(name,
+                                   IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                                   seq->streamindex,
+                                   seq->strip->colorspace_settings.name);
+          }
+          else {
+            sanim->anim = openanim_noload(name,
+                                          IB_rect |
+                                              ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                                          seq->streamindex,
+                                          seq->strip->colorspace_settings.name);
+          }
+
+          /* No individual view files - monoscopic, stereo 3d or EXR multi-view. */
+          totfiles = 1;
+        }
+
+        if (sanim->anim && use_proxy) {
+          seq_proxy_index_dir_set(sanim->anim, dir);
+        }
+      }
+      is_multiview_loaded = true;
+    }
+  }
+
+  if (is_multiview_loaded == false) {
+    StripAnim *sanim;
+
+    sanim = MEM_mallocN(sizeof(StripAnim), "Strip Anim");
+    BLI_addtail(&seq->anims, sanim);
+
+    if (openfile) {
+      sanim->anim = openanim(name,
+                             IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                             seq->streamindex,
+                             seq->strip->colorspace_settings.name);
+    }
+    else {
+      sanim->anim = openanim_noload(name,
+                                    IB_rect | ((seq->flag & SEQ_FILTERY) ? IB_animdeinterlace : 0),
+                                    seq->streamindex,
+                                    seq->strip->colorspace_settings.name);
+    }
+
+    if (sanim->anim && use_proxy) {
+      seq_proxy_index_dir_set(sanim->anim, dir);
+    }
+  }
+}
+
+static bool seq_proxy_get_custom_file_fname(Sequence *seq, char *name, const int view_id)
+{
+  char fname[FILE_MAXFILE];
+  char suffix[24];
+  StripProxy *proxy = seq->strip->proxy;
+
+  if (proxy == NULL) {
+    return false;
+  }
+
+  BLI_join_dirfile(fname, PROXY_MAXFILE, proxy->dir, proxy->file);
+  BLI_path_abs(fname, BKE_main_blendfile_path_from_global());
+
+  if (view_id > 0) {
+    BLI_snprintf(suffix, sizeof(suffix), "_%d", view_id);
+    /* TODO(sergey): This will actually append suffix after extension
+     * which is weird but how was originally coded in multi-view branch.
+     */
+    BLI_snprintf(name, PROXY_MAXFILE, "%s_%s", fname, suffix);
+  }
+  else {
+    BLI_strncpy(name, fname, PROXY_MAXFILE);
+  }
+
+  return true;
+}
+
+static bool seq_proxy_get_fname(Editing *ed,
+                                Sequence *seq,
+                                int cfra,
+                                eSpaceSeq_Proxy_RenderSize render_size,
+                                char *name,
+                                const int view_id)
+{
+  char dir[PROXY_MAXFILE];
+  char suffix[24] = {'\0'};
+  StripProxy *proxy = seq->strip->proxy;
+
+  if (proxy == NULL) {
+    return false;
+  }
+
+  /* Multi-view suffix. */
+  if (view_id > 0) {
+    BLI_snprintf(suffix, sizeof(suffix), "_%d", view_id);
+  }
+
+  /* Per strip with Custom file situation is handled separately. */
+  if (proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_FILE &&
+      ed->proxy_storage != SEQ_EDIT_PROXY_DIR_STORAGE) {
+    if (seq_proxy_get_custom_file_fname(seq, name, view_id)) {
+      return true;
+    }
+  }
+
+  if (ed->proxy_storage == SEQ_EDIT_PROXY_DIR_STORAGE) {
+    /* Per project default. */
+    if (ed->proxy_dir[0] == 0) {
+      BLI_strncpy(dir, "//BL_proxy", sizeof(dir));
+    }
+    else { /* Per project with custom dir. */
+      BLI_strncpy(dir, ed->proxy_dir, sizeof(dir));
+    }
+    BLI_path_abs(name, BKE_main_blendfile_path_from_global());
+  }
+  else {
+    /* Pre strip with custom dir. */
+    if (proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_DIR) {
+      BLI_strncpy(dir, seq->strip->proxy->dir, sizeof(dir));
+    }
+    else { /* Per strip default. */
+      BLI_snprintf(dir, PROXY_MAXFILE, "%s/BL_proxy", seq->strip->dir);
+    }
+  }
+
+  /* Proxy size number to be used in path. */
+  int proxy_size_number = BKE_sequencer_rendersize_to_scale_factor(render_size) * 100;
+
+  BLI_snprintf(name,
+               PROXY_MAXFILE,
+               "%s/images/%d/%s_proxy%s",
+               dir,
+               proxy_size_number,
+               BKE_sequencer_give_stripelem(seq, cfra)->name,
+               suffix);
+  BLI_path_abs(name, BKE_main_blendfile_path_from_global());
+  strcat(name, ".jpg");
+
+  return true;
+}
+
+static bool seq_can_use_proxy(Sequence *seq, IMB_Proxy_Size psize)
+{
+  if (seq->strip->proxy == NULL) {
+    return false;
+  }
+  short size_flags = seq->strip->proxy->build_size_flags;
+  return (seq->flag & SEQ_USE_PROXY) != 0 && psize != IMB_PROXY_NONE && (size_flags & psize) != 0;
+}
+
+static ImBuf *seq_proxy_fetch(const SeqRenderData *context, Sequence *seq, int cfra)
+{
+  char name[PROXY_MAXFILE];
+  StripProxy *proxy = seq->strip->proxy;
+  const eSpaceSeq_Proxy_RenderSize psize = context->preview_render_size;
+  Editing *ed = context->scene->ed;
+  StripAnim *sanim;
+
+  /* only use proxies, if they are enabled (even if present!) */
+  if (!seq_can_use_proxy(seq, seq_rendersize_to_proxysize(psize))) {
+    return NULL;
+  }
+
+  if (proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_FILE) {
+    int frameno = (int)BKE_sequencer_give_stripelem_index(seq, cfra) + seq->anim_startofs;
+    if (proxy->anim == NULL) {
+      if (seq_proxy_get_fname(ed, seq, cfra, psize, name, context->view_id) == 0) {
+        return NULL;
+      }
+
+      proxy->anim = openanim(name, IB_rect, 0, seq->strip->colorspace_settings.name);
+    }
+    if (proxy->anim == NULL) {
+      return NULL;
+    }
+
+    seq_open_anim_file(context->scene, seq, true);
+    sanim = seq->anims.first;
+
+    frameno = IMB_anim_index_get_frame_index(
+        sanim ? sanim->anim : NULL, seq->strip->proxy->tc, frameno);
+
+    return IMB_anim_absolute(proxy->anim, frameno, IMB_TC_NONE, IMB_PROXY_NONE);
+  }
+
+  if (seq_proxy_get_fname(ed, seq, cfra, psize, name, context->view_id) == 0) {
+    return NULL;
+  }
+
+  if (BLI_exists(name)) {
+    ImBuf *ibuf = IMB_loadiffname(name, IB_rect, NULL);
+
+    if (ibuf) {
+      sequencer_imbuf_assign_spaces(context->scene, ibuf);
+    }
+
+    return ibuf;
+  }
+
+  return NULL;
+}
+
+static void seq_proxy_build_frame(const SeqRenderData *context,
+                                  SeqRenderState *state,
+                                  Sequence *seq,
+                                  int cfra,
+                                  int proxy_render_size,
+                                  const bool overwrite)
+{
+  char name[PROXY_MAXFILE];
+  int quality;
+  int rectx, recty;
+  int ok;
+  ImBuf *ibuf_tmp, *ibuf;
+  Editing *ed = context->scene->ed;
+
+  if (!seq_proxy_get_fname(ed, seq, cfra, proxy_render_size, name, context->view_id)) {
+    return;
+  }
+
+  if (!overwrite && BLI_exists(name)) {
+    return;
+  }
+
+  ibuf_tmp = seq_render_strip(context, state, seq, cfra);
+
+  rectx = (proxy_render_size * ibuf_tmp->x) / 100;
+  recty = (proxy_render_size * ibuf_tmp->y) / 100;
+
+  if (ibuf_tmp->x != rectx || ibuf_tmp->y != recty) {
+    ibuf = IMB_dupImBuf(ibuf_tmp);
+    IMB_metadata_copy(ibuf, ibuf_tmp);
+    IMB_freeImBuf(ibuf_tmp);
+    IMB_scalefastImBuf(ibuf, (short)rectx, (short)recty);
+  }
+  else {
+    ibuf = ibuf_tmp;
+  }
+
+  /* depth = 32 is intentionally left in, otherwise ALPHA channels
+   * won't work... */
+  quality = seq->strip->proxy->quality;
+  ibuf->ftype = IMB_FTYPE_JPG;
+  ibuf->foptions.quality = quality;
+
+  /* unsupported feature only confuses other s/w */
+  if (ibuf->planes == 32) {
+    ibuf->planes = 24;
+  }
+
+  BLI_make_existing_file(name);
+
+  ok = IMB_saveiff(ibuf, name, IB_rect | IB_zbuf | IB_zbuffloat);
+  if (ok == 0) {
+    perror(name);
+  }
+
+  IMB_freeImBuf(ibuf);
+}
+
+/**
+ * Returns whether the file this context would read from even exist,
+ * if not, don't create the context
+ */
+static bool seq_proxy_multiview_context_invalid(Sequence *seq, Scene *scene, const int view_id)
+{
+  if ((scene->r.scemode & R_MULTIVIEW) == 0) {
+    return false;
+  }
+
+  if ((seq->type == SEQ_TYPE_IMAGE) && (seq->views_format == R_IMF_VIEWS_INDIVIDUAL)) {
+    static char prefix[FILE_MAX];
+    static const char *ext = NULL;
+    char str[FILE_MAX];
+
+    if (view_id == 0) {
+      char path[FILE_MAX];
+      BLI_join_dirfile(path, sizeof(path), seq->strip->dir, seq->strip->stripdata->name);
+      BLI_path_abs(path, BKE_main_blendfile_path_from_global());
+      BKE_scene_multiview_view_prefix_get(scene, path, prefix, &ext);
+    }
+    else {
+      prefix[0] = '\0';
+    }
+
+    if (prefix[0] == '\0') {
+      return view_id != 0;
+    }
+
+    seq_multiview_name(scene, view_id, prefix, ext, str, FILE_MAX);
+
+    if (BLI_access(str, R_OK) == 0) {
+      return false;
+    }
+
+    return view_id != 0;
+  }
+  return false;
+}
+
+/**
+ * This returns the maximum possible number of required contexts
+ */
+static int seq_proxy_context_count(Sequence *seq, Scene *scene)
+{
+  int num_views = 1;
+
+  if ((scene->r.scemode & R_MULTIVIEW) == 0) {
+    return 1;
+  }
+
+  switch (seq->type) {
+    case SEQ_TYPE_MOVIE: {
+      num_views = BLI_listbase_count(&seq->anims);
+      break;
+    }
+    case SEQ_TYPE_IMAGE: {
+      switch (seq->views_format) {
+        case R_IMF_VIEWS_INDIVIDUAL:
+          num_views = BKE_scene_multiview_num_views_get(&scene->r);
+          break;
+        case R_IMF_VIEWS_STEREO_3D:
+          num_views = 2;
+          break;
+        case R_IMF_VIEWS_MULTIVIEW:
+          /* not supported at the moment */
+          /* pass through */
+        default:
+          num_views = 1;
+      }
+      break;
+    }
+  }
+
+  return num_views;
+}
+
+bool BKE_sequencer_proxy_rebuild_context(Main *bmain,
+                                         Depsgraph *depsgraph,
+                                         Scene *scene,
+                                         Sequence *seq,
+                                         struct GSet *file_list,
+                                         ListBase *queue)
+{
+  SeqIndexBuildContext *context;
+  Sequence *nseq;
+  LinkData *link;
+  int num_files;
+  int i;
+
+  if (!seq->strip || !seq->strip->proxy) {
+    return true;
+  }
+
+  if (!(seq->flag & SEQ_USE_PROXY)) {
+    return true;
+  }
+
+  num_files = seq_proxy_context_count(seq, scene);
+
+  for (i = 0; i < num_files; i++) {
+    if (seq_proxy_multiview_context_invalid(seq, scene, i)) {
+      continue;
+    }
+
+    context = MEM_callocN(sizeof(SeqIndexBuildContext), "seq proxy rebuild context");
+
+    nseq = BKE_sequence_dupli_recursive(scene, scene, NULL, seq, 0);
+
+    context->tc_flags = nseq->strip->proxy->build_tc_flags;
+    context->size_flags = nseq->strip->proxy->build_size_flags;
+    context->quality = nseq->strip->proxy->quality;
+    context->overwrite = (nseq->strip->proxy->build_flags & SEQ_PROXY_SKIP_EXISTING) == 0;
+
+    context->bmain = bmain;
+    context->depsgraph = depsgraph;
+    context->scene = scene;
+    context->orig_seq = seq;
+    context->seq = nseq;
+
+    context->view_id = i; /* only for images */
+
+    if (nseq->type == SEQ_TYPE_MOVIE) {
+      StripAnim *sanim;
+
+      seq_open_anim_file(scene, nseq, true);
+      sanim = BLI_findlink(&nseq->anims, i);
+
+      if (sanim->anim) {
+        context->index_context = IMB_anim_index_rebuild_context(sanim->anim,
+                                                                context->tc_flags,
+                                                                context->size_flags,
+                                                                context->quality,
+                                                                context->overwrite,
+                                                                file_list);
+      }
+      if (!context->index_context) {
+        MEM_freeN(context);
+        return false;
+      }
+    }
+
+    link = BLI_genericNodeN(context);
+    BLI_addtail(queue, link);
+  }
+  return true;
+}
+
+void BKE_sequencer_proxy_rebuild(SeqIndexBuildContext *context,
+                                 short *stop,
+                                 short *do_update,
+                                 float *progress)
+{
+  const bool overwrite = context->overwrite;
+  SeqRenderData render_context;
+  Sequence *seq = context->seq;
+  Scene *scene = context->scene;
+  Main *bmain = context->bmain;
+  int cfra;
+
+  if (seq->type == SEQ_TYPE_MOVIE) {
+    if (context->index_context) {
+      IMB_anim_index_rebuild(context->index_context, stop, do_update, progress);
+    }
+
+    return;
+  }
+
+  if (!(seq->flag & SEQ_USE_PROXY)) {
+    return;
+  }
+
+  /* that's why it is called custom... */
+  if (seq->strip->proxy && seq->strip->proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_FILE) {
+    return;
+  }
+
+  /* fail safe code */
+
+  BKE_sequencer_new_render_data(bmain,
+                                context->depsgraph,
+                                context->scene,
+                                roundf((scene->r.size * (float)scene->r.xsch) / 100.0f),
+                                roundf((scene->r.size * (float)scene->r.ysch) / 100.0f),
+                                100,
+                                false,
+                                &render_context);
+
+  render_context.skip_cache = true;
+  render_context.is_proxy_render = true;
+  render_context.view_id = context->view_id;
+
+  SeqRenderState state;
+  sequencer_state_init(&state);
+
+  for (cfra = seq->startdisp + seq->startstill; cfra < seq->enddisp - seq->endstill; cfra++) {
+    if (context->size_flags & IMB_PROXY_25) {
+      seq_proxy_build_frame(&render_context, &state, seq, cfra, 25, overwrite);
+    }
+    if (context->size_flags & IMB_PROXY_50) {
+      seq_proxy_build_frame(&render_context, &state, seq, cfra, 50, overwrite);
+    }
+    if (context->size_flags & IMB_PROXY_75) {
+      seq_proxy_build_frame(&render_context, &state, seq, cfra, 75, overwrite);
+    }
+    if (context->size_flags & IMB_PROXY_100) {
+      seq_proxy_build_frame(&render_context, &state, seq, cfra, 100, overwrite);
+    }
+
+    *progress = (float)(cfra - seq->startdisp - seq->startstill) /
+                (seq->enddisp - seq->endstill - seq->startdisp - seq->startstill);
+    *do_update = true;
+
+    if (*stop || G.is_break) {
+      break;
+    }
+  }
+}
+
+void BKE_sequencer_proxy_rebuild_finish(SeqIndexBuildContext *context, bool stop)
+{
+  if (context->index_context) {
+    StripAnim *sanim;
+
+    for (sanim = context->seq->anims.first; sanim; sanim = sanim->next) {
+      IMB_close_anim_proxies(sanim->anim);
+    }
+
+    for (sanim = context->orig_seq->anims.first; sanim; sanim = sanim->next) {
+      IMB_close_anim_proxies(sanim->anim);
+    }
+
+    IMB_anim_index_rebuild_finish(context->index_context, stop);
+  }
+
+  seq_free_sequence_recurse(NULL, context->seq, true);
+
+  MEM_freeN(context);
+}
+
+void BKE_sequencer_proxy_set(struct Sequence *seq, bool value)
+{
+  if (value) {
+    seq->flag |= SEQ_USE_PROXY;
+    if (seq->strip->proxy == NULL) {
+      seq->strip->proxy = MEM_callocN(sizeof(struct StripProxy), "StripProxy");
+      seq->strip->proxy->quality = 90;
+      seq->strip->proxy->build_tc_flags = SEQ_PROXY_TC_ALL;
+      seq->strip->proxy->build_size_flags = SEQ_PROXY_IMAGE_SIZE_25;
+    }
+  }
+  else {
+    seq->flag &= ~SEQ_USE_PROXY;
+  }
+}
+
+/*********************** color balance *************************/
+
+static StripColorBalance calc_cb(StripColorBalance *cb_)
+{
+  StripColorBalance cb = *cb_;
+  int c;
+
+  for (c = 0; c < 3; c++) {
+    cb.lift[c] = 2.0f - cb.lift[c];
+  }
+
+  if (cb.flag & SEQ_COLOR_BALANCE_INVERSE_LIFT) {
+    for (c = 0; c < 3; c++) {
+      /* tweak to give more subtle results
+       * values above 1.0 are scaled */
+      if (cb.lift[c] > 1.0f) {
+        cb.lift[c] = pow(cb.lift[c] - 1.0f, 2.0) + 1.0;
+      }
+
+      cb.lift[c] = 2.0f - cb.lift[c];
+    }
+  }
+
+  if (cb.flag & SEQ_COLOR_BALANCE_INVERSE_GAIN) {
+    for (c = 0; c < 3; c++) {
+      if (cb.gain[c] != 0.0f) {
+        cb.gain[c] = 1.0f / cb.gain[c];
+      }
+      else {
+        cb.gain[c] = 1000000; /* should be enough :) */
+      }
+    }
+  }
+
+  if (!(cb.flag & SEQ_COLOR_BALANCE_INVERSE_GAMMA)) {
+    for (c = 0; c < 3; c++) {
+      if (cb.gamma[c] != 0.0f) {
+        cb.gamma[c] = 1.0f / cb.gamma[c];
+      }
+      else {
+        cb.gamma[c] = 1000000; /* should be enough :) */
+      }
+    }
+  }
+
+  return cb;
+}
+
+/* note: lift is actually 2-lift */
+MINLINE float color_balance_fl(
+    float in, const float lift, const float gain, const float gamma, const float mul)
+{
+  float x = (((in - 1.0f) * lift) + 1.0f) * gain;
+
+  /* prevent NaN */
+  if (x < 0.f) {
+    x = 0.f;
+  }
+
+  x = powf(x, gamma) * mul;
+  CLAMP(x, FLT_MIN, FLT_MAX);
+  return x;
+}
+
+static void make_cb_table_float(float lift, float gain, float gamma, float *table, float mul)
+{
+  int y;
+
+  for (y = 0; y < 256; y++) {
+    float v = color_balance_fl((float)y * (1.0f / 255.0f), lift, gain, gamma, mul);
+
+    table[y] = v;
+  }
+}
+
+static void color_balance_byte_byte(StripColorBalance *cb_,
+                                    unsigned char *rect,
+                                    unsigned char *mask_rect,
+                                    int width,
+                                    int height,
+                                    float mul)
+{
+  // unsigned char cb_tab[3][256];
+  unsigned char *cp = rect;
+  unsigned char *e = cp + width * 4 * height;
+  unsigned char *m = mask_rect;
+
+  StripColorBalance cb = calc_cb(cb_);
+
+  while (cp < e) {
+    float p[4];
+    int c;
+
+    straight_uchar_to_premul_float(p, cp);
+
+    for (c = 0; c < 3; c++) {
+      float t = color_balance_fl(p[c], cb.lift[c], cb.gain[c], cb.gamma[c], mul);
+
+      if (m) {
+        float m_normal = (float)m[c] / 255.0f;
+
+        p[c] = p[c] * (1.0f - m_normal) + t * m_normal;
+      }
+      else {
+        p[c] = t;
+      }
+    }
+
+    premul_float_to_straight_uchar(cp, p);
+
+    cp += 4;
+    if (m) {
+      m += 4;
+    }
+  }
+}
+
+static void color_balance_byte_float(StripColorBalance *cb_,
+                                     unsigned char *rect,
+                                     float *rect_float,
+                                     unsigned char *mask_rect,
+                                     int width,
+                                     int height,
+                                     float mul)
+{
+  float cb_tab[4][256];
+  int c, i;
+  unsigned char *p = rect;
+  unsigned char *e = p + width * 4 * height;
+  unsigned char *m = mask_rect;
+  float *o;
+  StripColorBalance cb;
+
+  o = rect_float;
+
+  cb = calc_cb(cb_);
+
+  for (c = 0; c < 3; c++) {
+    make_cb_table_float(cb.lift[c], cb.gain[c], cb.gamma[c], cb_tab[c], mul);
+  }
+
+  for (i = 0; i < 256; i++) {
+    cb_tab[3][i] = ((float)i) * (1.0f / 255.0f);
+  }
+
+  while (p < e) {
+    if (m) {
+      const float t[3] = {m[0] / 255.0f, m[1] / 255.0f, m[2] / 255.0f};
+
+      p[0] = p[0] * (1.0f - t[0]) + t[0] * cb_tab[0][p[0]];
+      p[1] = p[1] * (1.0f - t[1]) + t[1] * cb_tab[1][p[1]];
+      p[2] = p[2] * (1.0f - t[2]) + t[2] * cb_tab[2][p[2]];
+
+      m += 4;
+    }
+    else {
+      o[0] = cb_tab[0][p[0]];
+      o[1] = cb_tab[1][p[1]];
+      o[2] = cb_tab[2][p[2]];
+    }
+
+    o[3] = cb_tab[3][p[3]];
+
+    p += 4;
+    o += 4;
+  }
+}
+
+static void color_balance_float_float(StripColorBalance *cb_,
+                                      float *rect_float,
+                                      const float *mask_rect_float,
+                                      int width,
+                                      int height,
+                                      float mul)
+{
+  float *p = rect_float;
+  const float *e = rect_float + width * 4 * height;
+  const float *m = mask_rect_float;
+  StripColorBalance cb = calc_cb(cb_);
+
+  while (p < e) {
+    int c;
+    for (c = 0; c < 3; c++) {
+      float t = color_balance_fl(p[c], cb.lift[c], cb.gain[c], cb.gamma[c], mul);
+
+      if (m) {
+        p[c] = p[c] * (1.0f - m[c]) + t * m[c];
+      }
+      else {
+        p[c] = t;
+      }
+    }
+
+    p += 4;
+    if (m) {
+      m += 4;
+    }
+  }
+}
+
+typedef struct ColorBalanceInitData {
+  StripColorBalance *cb;
+  ImBuf *ibuf;
+  float mul;
+  ImBuf *mask;
+  bool make_float;
+} ColorBalanceInitData;
+
+typedef struct ColorBalanceThread {
+  StripColorBalance *cb;
+  float mul;
+
+  int width, height;
+
+  unsigned char *rect, *mask_rect;
+  float *rect_float, *mask_rect_float;
+
+  bool make_float;
+} ColorBalanceThread;
+
+static void color_balance_init_handle(void *handle_v,
+                                      int start_line,
+                                      int tot_line,
+                                      void *init_data_v)
+{
+  ColorBalanceThread *handle = (ColorBalanceThread *)handle_v;
+  ColorBalanceInitData *init_data = (ColorBalanceInitData *)init_data_v;
+  ImBuf *ibuf = init_data->ibuf;
+  ImBuf *mask = init_data->mask;
+
+  int offset = 4 * start_line * ibuf->x;
+
+  memset(handle, 0, sizeof(ColorBalanceThread));
+
+  handle->cb = init_data->cb;
+  handle->mul = init_data->mul;
+  handle->width = ibuf->x;
+  handle->height = tot_line;
+  handle->make_float = init_data->make_float;
+
+  if (ibuf->rect) {
+    handle->rect = (unsigned char *)ibuf->rect + offset;
+  }
+
+  if (ibuf->rect_float) {
+    handle->rect_float = ibuf->rect_float + offset;
+  }
+
+  if (mask) {
+    if (mask->rect) {
+      handle->mask_rect = (unsigned char *)mask->rect + offset;
+    }
+
+    if (mask->rect_float) {
+      handle->mask_rect_float = mask->rect_float + offset;
+    }
+  }
+  else {
+    handle->mask_rect = NULL;
+    handle->mask_rect_float = NULL;
+  }
+}
+
+static void *color_balance_do_thread(void *thread_data_v)
+{
+  ColorBalanceThread *thread_data = (ColorBalanceThread *)thread_data_v;
+  StripColorBalance *cb = thread_data->cb;
+  int width = thread_data->width, height = thread_data->height;
+  unsigned char *rect = thread_data->rect;
+  unsigned char *mask_rect = thread_data->mask_rect;
+  float *rect_float = thread_data->rect_float;
+  float *mask_rect_float = thread_data->mask_rect_float;
+  float mul = thread_data->mul;
+
+  if (rect_float) {
+    color_balance_float_float(cb, rect_float, mask_rect_float, width, height, mul);
+  }
+  else if (thread_data->make_float) {
+    color_balance_byte_float(cb, rect, rect_float, mask_rect, width, height, mul);
+  }
+  else {
+    color_balance_byte_byte(cb, rect, mask_rect, width, height, mul);
+  }
+
+  return NULL;
+}
+
+/**
+ * \a cfra is offset by \a fra_offset only in case we are using a real mask.
+ */
+ImBuf *BKE_sequencer_render_mask_input(const SeqRenderData *context,
+                                       int mask_input_type,
+                                       Sequence *mask_sequence,
+                                       Mask *mask_id,
+                                       int cfra,
+                                       int fra_offset,
+                                       bool make_float)
+{
+  ImBuf *mask_input = NULL;
+
+  if (mask_input_type == SEQUENCE_MASK_INPUT_STRIP) {
+    if (mask_sequence) {
+      SeqRenderState state;
+      sequencer_state_init(&state);
+
+      mask_input = seq_render_strip(context, &state, mask_sequence, cfra);
+
+      if (make_float) {
+        if (!mask_input->rect_float) {
+          IMB_float_from_rect(mask_input);
+        }
+      }
+      else {
+        if (!mask_input->rect) {
+          IMB_rect_from_float(mask_input);
+        }
+      }
+    }
+  }
+  else if (mask_input_type == SEQUENCE_MASK_INPUT_ID) {
+    mask_input = seq_render_mask(context, mask_id, cfra - fra_offset, make_float);
+  }
+
+  return mask_input;
+}
+
+void BKE_sequencer_color_balance_apply(
+    StripColorBalance *cb, ImBuf *ibuf, float mul, bool make_float, ImBuf *mask_input)
+{
+  ColorBalanceInitData init_data;
+
+  if (!ibuf->rect_float && make_float) {
+    imb_addrectfloatImBuf(ibuf);
+  }
+
+  init_data.cb = cb;
+  init_data.ibuf = ibuf;
+  init_data.mul = mul;
+  init_data.make_float = make_float;
+  init_data.mask = mask_input;
+
+  IMB_processor_apply_threaded(ibuf->y,
+                               sizeof(ColorBalanceThread),
+                               &init_data,
+                               color_balance_init_handle,
+                               color_balance_do_thread);
+
+  /* color balance either happens on float buffer or byte buffer, but never on both,
+   * free byte buffer if there's float buffer since float buffer would be used for
+   * color balance in favor of byte buffer
+   */
+  if (ibuf->rect_float && ibuf->rect) {
+    imb_freerectImBuf(ibuf);
+  }
+}
+
+/*
+ * input preprocessing for SEQ_TYPE_IMAGE, SEQ_TYPE_MOVIE, SEQ_TYPE_MOVIECLIP and SEQ_TYPE_SCENE
+ *
+ * Do all the things you can't really do afterwards using sequence effects
+ * (read: before rescaling to render resolution has been done)
+ *
+ * Order is important!
+ *
+ * - Deinterlace
+ * - Crop and transform in image source coordinate space
+ * - Flip X + Flip Y (could be done afterwards, backward compatibility)
+ * - Promote image to float data (affects pipeline operations afterwards)
+ * - Color balance (is most efficient in the byte -> float
+ *   (future: half -> float should also work fine!)
+ *   case, if done on load, since we can use lookup tables)
+ * - Premultiply
+ */
+
+bool BKE_sequencer_input_have_to_preprocess(const SeqRenderData *context,
+                                            Sequence *seq,
+                                            float UNUSED(cfra))
+{
+  float mul;
+
+  if (context && context->is_proxy_render) {
+    return false;
+  }
+
+  if (seq->flag &
+      (SEQ_FILTERY | SEQ_USE_CROP | SEQ_USE_TRANSFORM | SEQ_FLIPX | SEQ_FLIPY | SEQ_MAKE_FLOAT)) {
+    return true;
+  }
+
+  mul = seq->mul;
+
+  if (seq->blend_mode == SEQ_BLEND_REPLACE) {
+    mul *= seq->blend_opacity / 100.0f;
+  }
+
+  if (mul != 1.0f) {
+    return true;
+  }
+
+  if (seq->sat != 1.0f) {
+    return true;
+  }
+
+  if (seq->modifiers.first) {
+    return true;
+  }
+
+  return false;
+}
+
+static ImBuf *input_preprocess(const SeqRenderData *context,
+                               Sequence *seq,
+                               float cfra,
+                               ImBuf *ibuf,
+                               const bool is_proxy_image)
+{
+  Scene *scene = context->scene;
+  float mul;
+
+  ibuf = IMB_makeSingleUser(ibuf);
+
+  if ((seq->flag & SEQ_FILTERY) && !ELEM(seq->type, SEQ_TYPE_MOVIE, SEQ_TYPE_MOVIECLIP)) {
+    IMB_filtery(ibuf);
+  }
+
+  if (seq->flag & (SEQ_USE_CROP | SEQ_USE_TRANSFORM)) {
+    StripCrop c = {0};
+    StripTransform t = {0};
+
+    if (seq->flag & SEQ_USE_CROP && seq->strip->crop) {
+      c = *seq->strip->crop;
+    }
+    if (seq->flag & SEQ_USE_TRANSFORM && seq->strip->transform) {
+      t = *seq->strip->transform;
+    }
+
+    /* Calculate scale factor for current image if needed. */
+    double scale_factor, image_scale_factor = 1.0;
+    if (context->preview_render_size == SEQ_RENDER_SIZE_SCENE) {
+      scale_factor = image_scale_factor = (double)scene->r.size / 100;
+    }
+    else {
+      scale_factor = BKE_sequencer_rendersize_to_scale_factor(context->preview_render_size);
+      if (!is_proxy_image) {
+        image_scale_factor = scale_factor;
+      }
+    }
+
+    if (image_scale_factor != 1.0) {
+      if (context->for_render) {
+        IMB_scaleImBuf(ibuf, ibuf->x * image_scale_factor, ibuf->y * image_scale_factor);
+      }
+      else {
+        IMB_scalefastImBuf(ibuf, ibuf->x * image_scale_factor, ibuf->y * image_scale_factor);
+      }
+    }
+
+    t.xofs *= scale_factor;
+    t.yofs *= scale_factor;
+    c.left *= scale_factor;
+    c.right *= scale_factor;
+    c.top *= scale_factor;
+    c.bottom *= scale_factor;
+
+    int sx, sy, dx, dy;
+    sx = ibuf->x - c.left - c.right;
+    sy = ibuf->y - c.top - c.bottom;
+
+    if (seq->flag & SEQ_USE_TRANSFORM) {
+      dx = context->rectx;
+      dy = context->recty;
+    }
+    else {
+      dx = sx;
+      dy = sy;
+    }
+
+    if (c.top + c.bottom >= ibuf->y || c.left + c.right >= ibuf->x || t.xofs >= dx ||
+        t.yofs >= dy) {
+      return NULL;
+    }
+
+    ImBuf *i = IMB_allocImBuf(dx, dy, 32, ibuf->rect_float ? IB_rectfloat : IB_rect);
+    IMB_rectcpy(i, ibuf, t.xofs, t.yofs, c.left, c.bottom, sx, sy);
+    sequencer_imbuf_assign_spaces(scene, i);
+    IMB_metadata_copy(i, ibuf);
+    IMB_freeImBuf(ibuf);
+    ibuf = i;
+  }
+
+  if (seq->flag & SEQ_FLIPX) {
+    IMB_flipx(ibuf);
+  }
+
+  if (seq->flag & SEQ_FLIPY) {
+    IMB_flipy(ibuf);
+  }
+
+  if (seq->sat != 1.0f) {
+    IMB_saturation(ibuf, seq->sat);
+  }
+
+  mul = seq->mul;
+
+  if (seq->blend_mode == SEQ_BLEND_REPLACE) {
+    mul *= seq->blend_opacity / 100.0f;
+  }
+
+  if (seq->flag & SEQ_MAKE_FLOAT) {
+    if (!ibuf->rect_float) {
+      BKE_sequencer_imbuf_to_sequencer_space(scene, ibuf, true);
+    }
+
+    if (ibuf->rect) {
+      imb_freerectImBuf(ibuf);
+    }
+  }
+
+  if (mul != 1.0f) {
+    multibuf(ibuf, mul);
+  }
+
+  if (ibuf->x != context->rectx || ibuf->y != context->recty) {
+    if (context->for_render) {
+      IMB_scaleImBuf(ibuf, (short)context->rectx, (short)context->recty);
+    }
+    else {
+      IMB_scalefastImBuf(ibuf, (short)context->rectx, (short)context->recty);
+    }
+  }
+
+  if (seq->modifiers.first) {
+    ImBuf *ibuf_new = BKE_sequence_modifier_apply_stack(context, seq, ibuf, cfra);
+
+    if (ibuf_new != ibuf) {
+      IMB_metadata_copy(ibuf_new, ibuf);
+      IMB_freeImBuf(ibuf);
+      ibuf = ibuf_new;
+    }
+  }
+
+  return ibuf;
+}
+
+/*********************** strip rendering functions  *************************/
+
+typedef struct RenderEffectInitData {
+  struct SeqEffectHandle *sh;
+  const SeqRenderData *context;
+  Sequence *seq;
+  float cfra, facf0, facf1;
+  ImBuf *ibuf1, *ibuf2, *ibuf3;
+
+  ImBuf *out;
+} RenderEffectInitData;
+
+typedef struct RenderEffectThread {
+  struct SeqEffectHandle *sh;
+  const SeqRenderData *context;
+  Sequence *seq;
+  float cfra, facf0, facf1;
+  ImBuf *ibuf1, *ibuf2, *ibuf3;
+
+  ImBuf *out;
+  int start_line, tot_line;
+} RenderEffectThread;
+
+static void render_effect_execute_init_handle(void *handle_v,
+                                              int start_line,
+                                              int tot_line,
+                                              void *init_data_v)
+{
+  RenderEffectThread *handle = (RenderEffectThread *)handle_v;
+  RenderEffectInitData *init_data = (RenderEffectInitData *)init_data_v;
+
+  handle->sh = init_data->sh;
+  handle->context = init_data->context;
+  handle->seq = init_data->seq;
+  handle->cfra = init_data->cfra;
+  handle->facf0 = init_data->facf0;
+  handle->facf1 = init_data->facf1;
+  handle->ibuf1 = init_data->ibuf1;
+  handle->ibuf2 = init_data->ibuf2;
+  handle->ibuf3 = init_data->ibuf3;
+  handle->out = init_data->out;
+
+  handle->start_line = start_line;
+  handle->tot_line = tot_line;
+}
+
+static void *render_effect_execute_do_thread(void *thread_data_v)
+{
+  RenderEffectThread *thread_data = (RenderEffectThread *)thread_data_v;
+
+  thread_data->sh->execute_slice(thread_data->context,
+                                 thread_data->seq,
+                                 thread_data->cfra,
+                                 thread_data->facf0,
+                                 thread_data->facf1,
+                                 thread_data->ibuf1,
+                                 thread_data->ibuf2,
+                                 thread_data->ibuf3,
+                                 thread_data->start_line,
+                                 thread_data->tot_line,
+                                 thread_data->out);
+
+  return NULL;
+}
+
+ImBuf *BKE_sequencer_effect_execute_threaded(struct SeqEffectHandle *sh,
+                                             const SeqRenderData *context,
+                                             Sequence *seq,
+                                             float cfra,
+                                             float facf0,
+                                             float facf1,
+                                             ImBuf *ibuf1,
+                                             ImBuf *ibuf2,
+                                             ImBuf *ibuf3)
+{
+  RenderEffectInitData init_data;
+  ImBuf *out = sh->init_execution(context, ibuf1, ibuf2, ibuf3);
+
+  init_data.sh = sh;
+  init_data.context = context;
+  init_data.seq = seq;
+  init_data.cfra = cfra;
+  init_data.facf0 = facf0;
+  init_data.facf1 = facf1;
+  init_data.ibuf1 = ibuf1;
+  init_data.ibuf2 = ibuf2;
+  init_data.ibuf3 = ibuf3;
+  init_data.out = out;
+
+  IMB_processor_apply_threaded(out->y,
+                               sizeof(RenderEffectThread),
+                               &init_data,
+                               render_effect_execute_init_handle,
+                               render_effect_execute_do_thread);
+
+  return out;
+}
+
+static ImBuf *seq_render_effect_strip_impl(const SeqRenderData *context,
+                                           SeqRenderState *state,
+                                           Sequence *seq,
+                                           float cfra)
+{
+  Scene *scene = context->scene;
+  float fac, facf;
+  int early_out;
+  int i;
+  struct SeqEffectHandle sh = BKE_sequence_get_effect(seq);
+  FCurve *fcu = NULL;
+  ImBuf *ibuf[3];
+  Sequence *input[3];
+  ImBuf *out = NULL;
+
+  ibuf[0] = ibuf[1] = ibuf[2] = NULL;
+
+  input[0] = seq->seq1;
+  input[1] = seq->seq2;
+  input[2] = seq->seq3;
+
+  if (!sh.execute && !(sh.execute_slice && sh.init_execution)) {
+    /* effect not supported in this version... */
+    out = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+    return out;
+  }
+
+  if (seq->flag & SEQ_USE_EFFECT_DEFAULT_FADE) {
+    sh.get_default_fac(seq, cfra, &fac, &facf);
+    facf = fac;
+  }
+  else {
+    fcu = id_data_find_fcurve(&scene->id, seq, &RNA_Sequence, "effect_fader", 0, NULL);
+    if (fcu) {
+      fac = facf = evaluate_fcurve(fcu, cfra);
+    }
+    else {
+      fac = facf = seq->effect_fader;
+    }
+  }
+
+  early_out = sh.early_out(seq, fac, facf);
+
+  switch (early_out) {
+    case EARLY_NO_INPUT:
+      out = sh.execute(context, seq, cfra, fac, facf, NULL, NULL, NULL);
+      break;
+    case EARLY_DO_EFFECT:
+      for (i = 0; i < 3; i++) {
+        /* Speed effect requires time remapping of `cfra` for input(s). */
+        if (input[0] && seq->type == SEQ_TYPE_SPEED) {
+          float target_frame = BKE_sequencer_speed_effect_target_frame_get(context, seq, cfra, i);
+          ibuf[i] = seq_render_strip(context, state, input[0], target_frame);
+        }
+        else { /* Other effects. */
+          if (input[i]) {
+            ibuf[i] = seq_render_strip(context, state, input[i], cfra);
+          }
+        }
+      }
+
+      if (ibuf[0] && (ibuf[1] || BKE_sequence_effect_get_num_inputs(seq->type) == 1)) {
+        if (sh.multithreaded) {
+          out = BKE_sequencer_effect_execute_threaded(
+              &sh, context, seq, cfra, fac, facf, ibuf[0], ibuf[1], ibuf[2]);
+        }
+        else {
+          out = sh.execute(context, seq, cfra, fac, facf, ibuf[0], ibuf[1], ibuf[2]);
+        }
+      }
+      break;
+    case EARLY_USE_INPUT_1:
+      if (input[0]) {
+        out = seq_render_strip(context, state, input[0], cfra);
+      }
+      break;
+    case EARLY_USE_INPUT_2:
+      if (input[1]) {
+        out = seq_render_strip(context, state, input[1], cfra);
+      }
+      break;
+  }
+
+  for (i = 0; i < 3; i++) {
+    IMB_freeImBuf(ibuf[i]);
+  }
+
+  if (out == NULL) {
+    out = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+  }
+
+  return out;
+}
+
+/**
+ * Render individual view for multi-view or single (default view) for mono-view.
+ */
+static ImBuf *seq_render_image_strip_view(const SeqRenderData *context,
+                                          Sequence *seq,
+                                          char *name,
+                                          char *prefix,
+                                          const char *ext,
+                                          int view_id)
+{
+
+  ImBuf *ibuf = NULL;
+
+  int flag = IB_rect | IB_metadata;
+  if (seq->alpha_mode == SEQ_ALPHA_PREMUL) {
+    flag |= IB_alphamode_premul;
+  }
+
+  if (prefix[0] == '\0') {
+    ibuf = IMB_loadiffname(name, flag, seq->strip->colorspace_settings.name);
+  }
+  else {
+    char str[FILE_MAX];
+    BKE_scene_multiview_view_prefix_get(context->scene, name, prefix, &ext);
+    seq_multiview_name(context->scene, view_id, prefix, ext, str, FILE_MAX);
+    ibuf = IMB_loadiffname(str, flag, seq->strip->colorspace_settings.name);
+  }
+
+  if (ibuf == NULL) {
+    return NULL;
+  }
+
+  /* We don't need both (speed reasons)! */
+  if (ibuf->rect_float != NULL && ibuf->rect != NULL) {
+    imb_freerectImBuf(ibuf);
+  }
+
+  /* All sequencer color is done in SRGB space, linear gives odd cross-fades. */
+  BKE_sequencer_imbuf_to_sequencer_space(context->scene, ibuf, false);
+
+  return ibuf;
+}
+
+static bool seq_image_strip_is_multiview_render(
+    Scene *scene, Sequence *seq, int totfiles, char *name, char *r_prefix, const char *r_ext)
+{
+  if (totfiles > 1) {
+    BKE_scene_multiview_view_prefix_get(scene, name, r_prefix, &r_ext);
+    if (r_prefix[0] == '\0') {
+      return false;
+    }
+  }
+  else {
+    r_prefix[0] = '\0';
+  }
+
+  return (seq->flag & SEQ_USE_VIEWS) != 0 && (scene->r.scemode & R_MULTIVIEW) != 0;
+}
+
+static ImBuf *seq_render_image_strip(const SeqRenderData *context,
+                                     Sequence *seq,
+                                     float UNUSED(nr),
+                                     float cfra,
+                                     bool *r_is_proxy_image)
+{
+  char name[FILE_MAX];
+  const char *ext = NULL;
+  char prefix[FILE_MAX];
+  ImBuf *ibuf = NULL;
+
+  StripElem *s_elem = BKE_sequencer_give_stripelem(seq, cfra);
+  if (s_elem == NULL) {
+    return NULL;
+  }
+
+  BLI_join_dirfile(name, sizeof(name), seq->strip->dir, s_elem->name);
+  BLI_path_abs(name, BKE_main_blendfile_path_from_global());
+
+  /* Try to get a proxy image. */
+  ibuf = seq_proxy_fetch(context, seq, cfra);
+  if (ibuf != NULL) {
+    s_elem->orig_width = ibuf->x;
+    s_elem->orig_height = ibuf->y;
+    *r_is_proxy_image = true;
+    return ibuf;
+  }
+
+  /* Proxy not found, render original. */
+  const int totfiles = seq_num_files(context->scene, seq->views_format, true);
+  bool is_multiview_render = seq_image_strip_is_multiview_render(
+      context->scene, seq, totfiles, name, prefix, ext);
+
+  if (is_multiview_render) {
+    int totviews = BKE_scene_multiview_num_views_get(&context->scene->r);
+    ImBuf **ibufs_arr = MEM_callocN(sizeof(ImBuf *) * totviews, "Sequence Image Views Imbufs");
+
+    for (int view_id = 0; view_id < totfiles; view_id++) {
+      ibufs_arr[view_id] = seq_render_image_strip_view(context, seq, name, prefix, ext, view_id);
+    }
+
+    if (ibufs_arr[0] == NULL) {
+      return NULL;
+    }
+
+    if (seq->views_format == R_IMF_VIEWS_STEREO_3D) {
+      IMB_ImBufFromStereo3d(seq->stereo3d_format, ibufs_arr[0], &ibufs_arr[0], &ibufs_arr[1]);
+    }
+
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      SeqRenderData localcontext = *context;
+      localcontext.view_id = view_id;
+
+      if (view_id != context->view_id) {
+        ibufs_arr[view_id] = seq_render_preprocess_ibuf(
+            &localcontext, seq, ibufs_arr[view_id], cfra, clock(), true, false);
+      }
+    }
+
+    /* Return the original requested ImBuf. */
+    ibuf = ibufs_arr[context->view_id];
+
+    /* Remove the others (decrease their refcount). */
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      if (ibufs_arr[view_id] != ibuf) {
+        IMB_freeImBuf(ibufs_arr[view_id]);
+      }
+    }
+
+    MEM_freeN(ibufs_arr);
+  }
+  else {
+    ibuf = seq_render_image_strip_view(context, seq, name, prefix, ext, context->view_id);
+  }
+
+  if (ibuf == NULL) {
+    return NULL;
+  }
+
+  s_elem->orig_width = ibuf->x;
+  s_elem->orig_height = ibuf->y;
+
+  return ibuf;
+}
+
+static ImBuf *seq_render_movie_strip_custom_file_proxy(const SeqRenderData *context,
+                                                       Sequence *seq,
+                                                       int cfra)
+{
+  char name[PROXY_MAXFILE];
+  StripProxy *proxy = seq->strip->proxy;
+
+  if (proxy->anim == NULL) {
+    if (seq_proxy_get_custom_file_fname(seq, name, context->view_id)) {
+      proxy->anim = openanim(name, IB_rect, 0, seq->strip->colorspace_settings.name);
+    }
+    if (proxy->anim == NULL) {
+      return NULL;
+    }
+  }
+
+  int frameno = (int)BKE_sequencer_give_stripelem_index(seq, cfra) + seq->anim_startofs;
+  return IMB_anim_absolute(proxy->anim, frameno, IMB_TC_NONE, IMB_PROXY_NONE);
+}
+
+/**
+ * Render individual view for multi-view or single (default view) for mono-view.
+ */
+static ImBuf *seq_render_movie_strip_view(const SeqRenderData *context,
+                                          Sequence *seq,
+                                          float nr,
+                                          float cfra,
+                                          StripAnim *sanim,
+                                          bool *r_is_proxy_image)
+{
+  ImBuf *ibuf = NULL;
+  IMB_Proxy_Size psize = seq_rendersize_to_proxysize(context->preview_render_size);
+
+  IMB_anim_set_preseek(sanim->anim, seq->anim_preseek);
+
+  if (seq_can_use_proxy(seq, psize)) {
+    /* Try to get a proxy image.
+     * Movie proxies are handled by ImBuf module with exception of `custom file` setting. */
+    if (context->scene->ed->proxy_storage != SEQ_EDIT_PROXY_DIR_STORAGE &&
+        seq->strip->proxy->storage & SEQ_STORAGE_PROXY_CUSTOM_FILE) {
+      ibuf = seq_render_movie_strip_custom_file_proxy(context, seq, cfra);
+    }
+    else {
+      ibuf = IMB_anim_absolute(sanim->anim,
+                               nr + seq->anim_startofs,
+                               seq->strip->proxy ? seq->strip->proxy->tc : IMB_TC_RECORD_RUN,
+                               psize);
+    }
+
+    if (ibuf != NULL) {
+      *r_is_proxy_image = true;
+    }
+  }
+
+  /* Fetching for requested proxy size failed, try fetching the original instead. */
+  if (ibuf == NULL) {
+    ibuf = IMB_anim_absolute(sanim->anim,
+                             nr + seq->anim_startofs,
+                             seq->strip->proxy ? seq->strip->proxy->tc : IMB_TC_RECORD_RUN,
+                             IMB_PROXY_NONE);
+  }
+  if (ibuf == NULL) {
+    return NULL;
+  }
+
+  BKE_sequencer_imbuf_to_sequencer_space(context->scene, ibuf, false);
+
+  /* We don't need both (speed reasons)! */
+  if (ibuf->rect_float != NULL && ibuf->rect != NULL) {
+    imb_freerectImBuf(ibuf);
+  }
+
+  return ibuf;
+}
+
+static ImBuf *seq_render_movie_strip(
+    const SeqRenderData *context, Sequence *seq, float nr, float cfra, bool *r_is_proxy_image)
+{
+  /* Load all the videos. */
+  seq_open_anim_file(context->scene, seq, false);
+
+  ImBuf *ibuf = NULL;
+  StripAnim *sanim = seq->anims.first;
+  const int totfiles = seq_num_files(context->scene, seq->views_format, true);
+  bool is_multiview_render = (seq->flag & SEQ_USE_VIEWS) != 0 &&
+                             (context->scene->r.scemode & R_MULTIVIEW) != 0 &&
+                             BLI_listbase_count_at_most(&seq->anims, totfiles + 1) == totfiles;
+
+  if (is_multiview_render) {
+    ImBuf **ibuf_arr;
+    int totviews = BKE_scene_multiview_num_views_get(&context->scene->r);
+    ibuf_arr = MEM_callocN(sizeof(ImBuf *) * totviews, "Sequence Image Views Imbufs");
+    int ibuf_view_id;
+
+    for (ibuf_view_id = 0, sanim = seq->anims.first; sanim; sanim = sanim->next, ibuf_view_id++) {
+      if (sanim->anim) {
+        ibuf_arr[ibuf_view_id] = seq_render_movie_strip_view(
+            context, seq, nr, cfra, sanim, r_is_proxy_image);
+      }
+    }
+
+    if (seq->views_format == R_IMF_VIEWS_STEREO_3D) {
+      if (ibuf_arr[0] == NULL) {
+        /* Probably proxy hasn't been created yet. */
+        MEM_freeN(ibuf_arr);
+        return NULL;
+      }
+
+      IMB_ImBufFromStereo3d(seq->stereo3d_format, ibuf_arr[0], &ibuf_arr[0], &ibuf_arr[1]);
+    }
+
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      SeqRenderData localcontext = *context;
+      localcontext.view_id = view_id;
+
+      if (view_id != context->view_id) {
+        ibuf_arr[view_id] = seq_render_preprocess_ibuf(
+            &localcontext, seq, ibuf_arr[view_id], cfra, clock(), true, false);
+      }
+    }
+
+    /* Return the original requested ImBuf. */
+    ibuf = ibuf_arr[context->view_id];
+
+    /* Remove the others (decrease their refcount). */
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      if (ibuf_arr[view_id] != ibuf) {
+        IMB_freeImBuf(ibuf_arr[view_id]);
+      }
+    }
+
+    MEM_freeN(ibuf_arr);
+  }
+  else {
+    ibuf = seq_render_movie_strip_view(context, seq, nr, cfra, sanim, r_is_proxy_image);
+  }
+
+  if (ibuf == NULL) {
+    return NULL;
+  }
+
+  seq->strip->stripdata->orig_width = ibuf->x;
+  seq->strip->stripdata->orig_height = ibuf->y;
+
+  return ibuf;
+}
+
+static ImBuf *seq_get_movieclip_ibuf(Sequence *seq, MovieClipUser user)
+{
+  ImBuf *ibuf = NULL;
+  float tloc[2], tscale, tangle;
+  if (seq->clip_flag & SEQ_MOVIECLIP_RENDER_STABILIZED) {
+    ibuf = BKE_movieclip_get_stable_ibuf(seq->clip, &user, tloc, &tscale, &tangle, 0);
+  }
+  else {
+    ibuf = BKE_movieclip_get_ibuf_flag(seq->clip, &user, seq->clip->flag, MOVIECLIP_CACHE_SKIP);
+  }
+  return ibuf;
+}
+
+static ImBuf *seq_render_movieclip_strip(const SeqRenderData *context,
+                                         Sequence *seq,
+                                         float nr,
+                                         bool *r_is_proxy_image)
+{
+  ImBuf *ibuf = NULL;
+  MovieClipUser user;
+  IMB_Proxy_Size psize = seq_rendersize_to_proxysize(context->preview_render_size);
+
+  if (!seq->clip) {
+    return NULL;
+  }
+
+  memset(&user, 0, sizeof(MovieClipUser));
+
+  BKE_movieclip_user_set_frame(&user, nr + seq->anim_startofs + seq->clip->start_frame);
+
+  user.render_size = MCLIP_PROXY_RENDER_SIZE_FULL;
+  switch (psize) {
+    case IMB_PROXY_NONE:
+      user.render_size = MCLIP_PROXY_RENDER_SIZE_FULL;
+      break;
+    case IMB_PROXY_100:
+      user.render_size = MCLIP_PROXY_RENDER_SIZE_100;
+      break;
+    case IMB_PROXY_75:
+      user.render_size = MCLIP_PROXY_RENDER_SIZE_75;
+      break;
+    case IMB_PROXY_50:
+      user.render_size = MCLIP_PROXY_RENDER_SIZE_50;
+      break;
+    case IMB_PROXY_25:
+      user.render_size = MCLIP_PROXY_RENDER_SIZE_25;
+      break;
+  }
+
+  if (seq->clip_flag & SEQ_MOVIECLIP_RENDER_UNDISTORTED) {
+    user.render_flag |= MCLIP_PROXY_RENDER_UNDISTORT;
+  }
+
+  /* Try to get a proxy image. */
+  ibuf = seq_get_movieclip_ibuf(seq, user);
+
+  if (ibuf != NULL && psize != IMB_PROXY_NONE) {
+    *r_is_proxy_image = true;
+  }
+
+  /* If proxy is not found, grab full-size frame. */
+  if (ibuf == NULL) {
+    user.render_flag |= MCLIP_PROXY_RENDER_USE_FALLBACK_RENDER;
+    ibuf = seq_get_movieclip_ibuf(seq, user);
+  }
+
+  return ibuf;
+}
+
+static ImBuf *seq_render_mask(const SeqRenderData *context, Mask *mask, float nr, bool make_float)
+{
+  /* TODO - add option to rasterize to alpha imbuf? */
+  ImBuf *ibuf = NULL;
+  float *maskbuf;
+  int i;
+
+  if (!mask) {
+    return NULL;
+  }
+
+  AnimData *adt;
+  Mask *mask_temp;
+  MaskRasterHandle *mr_handle;
+
+  mask_temp = BKE_mask_copy_nolib(mask);
+
+  BKE_mask_evaluate(mask_temp, mask->sfra + nr, true);
+
+  /* anim-data */
+  adt = BKE_animdata_from_id(&mask->id);
+  const AnimationEvalContext anim_eval_context = BKE_animsys_eval_context_construct(
+      context->depsgraph, mask->sfra + nr);
+  BKE_animsys_evaluate_animdata(&mask_temp->id, adt, &anim_eval_context, ADT_RECALC_ANIM, false);
+
+  maskbuf = MEM_mallocN(sizeof(float) * context->rectx * context->recty, __func__);
+
+  mr_handle = BKE_maskrasterize_handle_new();
+
+  BKE_maskrasterize_handle_init(
+      mr_handle, mask_temp, context->rectx, context->recty, true, true, true);
+
+  BKE_mask_free(mask_temp);
+  MEM_freeN(mask_temp);
+
+  BKE_maskrasterize_buffer(mr_handle, context->rectx, context->recty, maskbuf);
+
+  BKE_maskrasterize_handle_free(mr_handle);
+
+  if (make_float) {
+    /* pixels */
+    const float *fp_src;
+    float *fp_dst;
+
+    ibuf = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rectfloat);
+
+    fp_src = maskbuf;
+    fp_dst = ibuf->rect_float;
+    i = context->rectx * context->recty;
+    while (--i) {
+      fp_dst[0] = fp_dst[1] = fp_dst[2] = *fp_src;
+      fp_dst[3] = 1.0f;
+
+      fp_src += 1;
+      fp_dst += 4;
+    }
+  }
+  else {
+    /* pixels */
+    const float *fp_src;
+    unsigned char *ub_dst;
+
+    ibuf = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+
+    fp_src = maskbuf;
+    ub_dst = (unsigned char *)ibuf->rect;
+    i = context->rectx * context->recty;
+    while (--i) {
+      ub_dst[0] = ub_dst[1] = ub_dst[2] = (unsigned char)(*fp_src * 255.0f); /* already clamped */
+      ub_dst[3] = 255;
+
+      fp_src += 1;
+      ub_dst += 4;
+    }
+  }
+
+  MEM_freeN(maskbuf);
+
+  return ibuf;
+}
+
+static ImBuf *seq_render_mask_strip(const SeqRenderData *context, Sequence *seq, float nr)
+{
+  bool make_float = (seq->flag & SEQ_MAKE_FLOAT) != 0;
+
+  return seq_render_mask(context, seq->mask, nr, make_float);
+}
+
+static ImBuf *seq_render_scene_strip(const SeqRenderData *context,
+                                     Sequence *seq,
+                                     float nr,
+                                     float cfra)
+{
+  ImBuf *ibuf = NULL;
+  double frame;
+  Object *camera;
+
+  struct {
+    int scemode;
+    int cfra;
+    float subframe;
+
+#ifdef DURIAN_CAMERA_SWITCH
+    int mode;
+#endif
+  } orig_data;
+
+  /* Old info:
+   * Hack! This function can be called from do_render_seq(), in that case
+   * the seq->scene can already have a Render initialized with same name,
+   * so we have to use a default name. (compositor uses scene name to
+   * find render).
+   * However, when called from within the UI (image preview in sequencer)
+   * we do want to use scene Render, that way the render result is defined
+   * for display in render/imagewindow
+   *
+   * Hmm, don't see, why we can't do that all the time,
+   * and since G.is_rendering is uhm, gone... (Peter)
+   */
+
+  /* New info:
+   * Using the same name for the renders works just fine as the do_render_seq()
+   * render is not used while the scene strips are rendered.
+   *
+   * However rendering from UI (through sequencer_preview_area_draw) can crash in
+   * very many cases since other renders (material preview, an actual render etc.)
+   * can be started while this sequence preview render is running. The only proper
+   * solution is to make the sequencer preview render a proper job, which can be
+   * stopped when needed. This would also give a nice progress bar for the preview
+   * space so that users know there's something happening.
+   *
+   * As a result the active scene now only uses OpenGL rendering for the sequencer
+   * preview. This is far from nice, but is the only way to prevent crashes at this
+   * time.
+   *
+   * -jahka
+   */
+
+  const bool is_rendering = G.is_rendering;
+  const bool is_background = G.background;
+  const bool do_seq_gl = is_rendering ? 0 : (context->scene->r.seq_prev_type) != OB_RENDER;
+  bool have_comp = false;
+  bool use_gpencil = true;
+  /* do we need to re-evaluate the frame after rendering? */
+  bool is_frame_update = false;
+  Scene *scene;
+  int is_thread_main = BLI_thread_is_main();
+
+  /* don't refer to seq->scene above this point!, it can be NULL */
+  if (seq->scene == NULL) {
+    return NULL;
+  }
+
+  /* Prevent rendering scene recursively. */
+  if (seq->scene == context->scene) {
+    return NULL;
+  }
+
+  scene = seq->scene;
+  frame = (double)scene->r.sfra + (double)nr + (double)seq->anim_startofs;
+
+#if 0 /* UNUSED */
+  have_seq = (scene->r.scemode & R_DOSEQ) && scene->ed && scene->ed->seqbase.first);
+#endif
+  have_comp = (scene->r.scemode & R_DOCOMP) && scene->use_nodes && scene->nodetree;
+
+  /* Get view layer for the strip. */
+  ViewLayer *view_layer = BKE_view_layer_default_render(scene);
+  /* Depsgraph will be NULL when doing rendering. */
+  Depsgraph *depsgraph = NULL;
+
+  orig_data.scemode = scene->r.scemode;
+  orig_data.cfra = scene->r.cfra;
+  orig_data.subframe = scene->r.subframe;
+#ifdef DURIAN_CAMERA_SWITCH
+  orig_data.mode = scene->r.mode;
+#endif
+
+  BKE_scene_frame_set(scene, frame);
+
+  if (seq->scene_camera) {
+    camera = seq->scene_camera;
+  }
+  else {
+    BKE_scene_camera_switch_update(scene);
+    camera = scene->camera;
+  }
+
+  if (have_comp == false && camera == NULL) {
+    goto finally;
+  }
+
+  if (seq->flag & SEQ_SCENE_NO_GPENCIL) {
+    use_gpencil = false;
+  }
+
+  /* prevent eternal loop */
+  scene->r.scemode &= ~R_DOSEQ;
+
+#ifdef DURIAN_CAMERA_SWITCH
+  /* stooping to new low's in hackyness :( */
+  scene->r.mode |= R_NO_CAMERA_SWITCH;
+#endif
+
+  is_frame_update = (orig_data.cfra != scene->r.cfra) || (orig_data.subframe != scene->r.subframe);
+
+  if ((sequencer_view3d_fn && do_seq_gl && camera) && is_thread_main) {
+    char err_out[256] = "unknown";
+    const int width = (scene->r.xsch * scene->r.size) / 100;
+    const int height = (scene->r.ysch * scene->r.size) / 100;
+    const char *viewname = BKE_scene_multiview_render_view_name_get(&scene->r, context->view_id);
+
+    unsigned int draw_flags = V3D_OFSDRAW_NONE;
+    draw_flags |= (use_gpencil) ? V3D_OFSDRAW_SHOW_ANNOTATION : 0;
+    draw_flags |= (context->scene->r.seq_flag & R_SEQ_OVERRIDE_SCENE_SETTINGS) ?
+                      V3D_OFSDRAW_OVERRIDE_SCENE_SETTINGS :
+                      0;
+
+    /* for old scene this can be uninitialized,
+     * should probably be added to do_versions at some point if the functionality stays */
+    if (context->scene->r.seq_prev_type == 0) {
+      context->scene->r.seq_prev_type = 3 /* == OB_SOLID */;
+    }
+
+    /* opengl offscreen render */
+    depsgraph = BKE_scene_ensure_depsgraph(context->bmain, scene, view_layer);
+    BKE_scene_graph_update_for_newframe(depsgraph);
+    ibuf = sequencer_view3d_fn(
+        /* set for OpenGL render (NULL when scrubbing) */
+        depsgraph,
+        scene,
+        &context->scene->display.shading,
+        context->scene->r.seq_prev_type,
+        camera,
+        width,
+        height,
+        IB_rect,
+        draw_flags,
+        scene->r.alphamode,
+        viewname,
+        context->gpu_offscreen,
+        err_out);
+    if (ibuf == NULL) {
+      fprintf(stderr, "seq_render_scene_strip failed to get opengl buffer: %s\n", err_out);
+    }
+  }
+  else {
+    Render *re = RE_GetSceneRender(scene);
+    const int totviews = BKE_scene_multiview_num_views_get(&scene->r);
+    ImBuf **ibufs_arr;
+
+    ibufs_arr = MEM_callocN(sizeof(ImBuf *) * totviews, "Sequence Image Views Imbufs");
+
+    /* XXX: this if can be removed when sequence preview rendering uses the job system
+     *
+     * disable rendered preview for sequencer while rendering -- it's very much possible
+     * that preview render will went into conflict with final render
+     *
+     * When rendering from command line renderer is called from main thread, in this
+     * case it's always safe to render scene here
+     */
+    if (!is_thread_main || is_rendering == false || is_background || context->for_render) {
+      if (re == NULL) {
+        re = RE_NewSceneRender(scene);
+      }
+
+      RE_RenderFrame(
+          re, context->bmain, scene, have_comp ? NULL : view_layer, camera, frame, false);
+
+      /* restore previous state after it was toggled on & off by RE_RenderFrame */
+      G.is_rendering = is_rendering;
+    }
+
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      SeqRenderData localcontext = *context;
+      RenderResult rres;
+
+      localcontext.view_id = view_id;
+
+      RE_AcquireResultImage(re, &rres, view_id);
+
+      if (rres.rectf) {
+        ibufs_arr[view_id] = IMB_allocImBuf(rres.rectx, rres.recty, 32, IB_rectfloat);
+        memcpy(ibufs_arr[view_id]->rect_float,
+               rres.rectf,
+               sizeof(float[4]) * rres.rectx * rres.recty);
+
+        if (rres.rectz) {
+          addzbuffloatImBuf(ibufs_arr[view_id]);
+          memcpy(
+              ibufs_arr[view_id]->zbuf_float, rres.rectz, sizeof(float) * rres.rectx * rres.recty);
+        }
+
+        /* float buffers in the sequencer are not linear */
+        BKE_sequencer_imbuf_to_sequencer_space(context->scene, ibufs_arr[view_id], false);
+      }
+      else if (rres.rect32) {
+        ibufs_arr[view_id] = IMB_allocImBuf(rres.rectx, rres.recty, 32, IB_rect);
+        memcpy(ibufs_arr[view_id]->rect, rres.rect32, 4 * rres.rectx * rres.recty);
+      }
+
+      if (view_id != context->view_id) {
+        BKE_sequencer_cache_put(
+            &localcontext, seq, cfra, SEQ_CACHE_STORE_RAW, ibufs_arr[view_id], 0, false);
+      }
+
+      RE_ReleaseResultImage(re);
+    }
+
+    /* return the original requested ImBuf */
+    ibuf = ibufs_arr[context->view_id];
+
+    /* "remove" the others (decrease their refcount) */
+    for (int view_id = 0; view_id < totviews; view_id++) {
+      if (ibufs_arr[view_id] != ibuf) {
+        IMB_freeImBuf(ibufs_arr[view_id]);
+      }
+    }
+    MEM_freeN(ibufs_arr);
+  }
+
+finally:
+  /* restore */
+  scene->r.scemode = orig_data.scemode;
+  scene->r.cfra = orig_data.cfra;
+  scene->r.subframe = orig_data.subframe;
+
+  if (is_frame_update && (depsgraph != NULL)) {
+    BKE_scene_graph_update_for_newframe(depsgraph);
+  }
+
+#ifdef DURIAN_CAMERA_SWITCH
+  /* stooping to new low's in hackyness :( */
+  scene->r.mode &= orig_data.mode | ~R_NO_CAMERA_SWITCH;
+#endif
+
+  return ibuf;
+}
+
+/**
+ * Used for meta-strips & scenes with #SEQ_SCENE_STRIPS flag set.
+ */
+static ImBuf *do_render_strip_seqbase(const SeqRenderData *context,
+                                      SeqRenderState *state,
+                                      Sequence *seq,
+                                      float nr)
+{
+  ImBuf *ibuf = NULL;
+  ListBase *seqbase = NULL;
+  int offset;
+
+  seqbase = BKE_sequence_seqbase_get(seq, &offset);
+
+  if (seqbase && !BLI_listbase_is_empty(seqbase)) {
+
+    if (seq->flag & SEQ_SCENE_STRIPS && seq->scene) {
+      BKE_animsys_evaluate_all_animation(context->bmain, context->depsgraph, nr + offset);
+    }
+
+    ibuf = seq_render_strip_stack(context,
+                                  state,
+                                  seqbase,
+                                  /* scene strips don't have their start taken into account */
+                                  nr + offset,
+                                  0);
+  }
+
+  return ibuf;
+}
+
+static ImBuf *do_render_strip_uncached(const SeqRenderData *context,
+                                       SeqRenderState *state,
+                                       Sequence *seq,
+                                       float cfra,
+                                       bool *r_is_proxy_image)
+{
+  ImBuf *ibuf = NULL;
+  float nr = BKE_sequencer_give_stripelem_index(seq, cfra);
+  int type = (seq->type & SEQ_TYPE_EFFECT) ? SEQ_TYPE_EFFECT : seq->type;
+  switch (type) {
+    case SEQ_TYPE_META: {
+      ibuf = do_render_strip_seqbase(context, state, seq, nr);
+      break;
+    }
+
+    case SEQ_TYPE_SCENE: {
+      if (seq->flag & SEQ_SCENE_STRIPS) {
+        if (seq->scene && (context->scene != seq->scene)) {
+          /* recursive check */
+          if (BLI_linklist_index(state->scene_parents, seq->scene) != -1) {
+            break;
+          }
+          LinkNode scene_parent = {
+              .next = state->scene_parents,
+              .link = seq->scene,
+          };
+          state->scene_parents = &scene_parent;
+          /* end check */
+
+          /* Use the Scene Seq's scene for the context when rendering the scene's sequences
+           * (necessary for Multicam Selector among others).
+           */
+          SeqRenderData local_context = *context;
+          local_context.scene = seq->scene;
+          local_context.skip_cache = true;
+
+          ibuf = do_render_strip_seqbase(&local_context, state, seq, nr);
+
+          /* step back in the list */
+          state->scene_parents = state->scene_parents->next;
+        }
+      }
+      else {
+        /* scene can be NULL after deletions */
+        ibuf = seq_render_scene_strip(context, seq, nr, cfra);
+      }
+
+      break;
+    }
+
+    case SEQ_TYPE_EFFECT: {
+      ibuf = seq_render_effect_strip_impl(context, state, seq, cfra);
+      break;
+    }
+
+    case SEQ_TYPE_IMAGE: {
+      ibuf = seq_render_image_strip(context, seq, nr, cfra, r_is_proxy_image);
+      break;
+    }
+
+    case SEQ_TYPE_MOVIE: {
+      ibuf = seq_render_movie_strip(context, seq, nr, cfra, r_is_proxy_image);
+      break;
+    }
+
+    case SEQ_TYPE_MOVIECLIP: {
+      ibuf = seq_render_movieclip_strip(context, seq, nr, r_is_proxy_image);
+
+      if (ibuf) {
+        /* duplicate frame so movie cache wouldn't be confused by sequencer's stuff */
+        ImBuf *i = IMB_dupImBuf(ibuf);
+        IMB_freeImBuf(ibuf);
+        ibuf = i;
+
+        if (ibuf->rect_float) {
+          BKE_sequencer_imbuf_to_sequencer_space(context->scene, ibuf, false);
+        }
+      }
+
+      break;
+    }
+
+    case SEQ_TYPE_MASK: {
+      /* ibuf is always new */
+      ibuf = seq_render_mask_strip(context, seq, nr);
+      break;
+    }
+  }
+
+  if (ibuf) {
+    sequencer_imbuf_assign_spaces(context->scene, ibuf);
+  }
+
+  return ibuf;
+}
+
+/* Estimate time spent by the program rendering the strip */
+static clock_t seq_estimate_render_cost_begin(void)
+{
+  return clock();
+}
+
+static float seq_estimate_render_cost_end(Scene *scene, clock_t begin)
+{
+  clock_t end = clock();
+  float time_spent = (float)(end - begin);
+  float time_max = (1.0f / scene->r.frs_sec) * CLOCKS_PER_SEC;
+
+  if (time_max != 0) {
+    return time_spent / time_max;
+  }
+
+  return 1;
+}
+
+static ImBuf *seq_render_preprocess_ibuf(const SeqRenderData *context,
+                                         Sequence *seq,
+                                         ImBuf *ibuf,
+                                         float cfra,
+                                         clock_t begin,
+                                         bool use_preprocess,
+                                         const bool is_proxy_image)
+{
+  if (context->is_proxy_render == false &&
+      (ibuf->x != context->rectx || ibuf->y != context->recty)) {
+    use_preprocess = true;
+  }
+
+  if (use_preprocess) {
+    float cost = seq_estimate_render_cost_end(context->scene, begin);
+
+    /* TODO(Richard): It should be possible to store in cache if image is proxy,
+     * but it adds quite a bit of complexity. Since proxies are fast to read, I would
+     * rather simplify existing code a bit. */
+    if (!is_proxy_image) {
+      BKE_sequencer_cache_put(context, seq, cfra, SEQ_CACHE_STORE_RAW, ibuf, cost, false);
+    }
+
+    /* Reset timer so we can get partial render time. */
+    begin = seq_estimate_render_cost_begin();
+    ibuf = input_preprocess(context, seq, cfra, ibuf, is_proxy_image);
+  }
+
+  float cost = seq_estimate_render_cost_end(context->scene, begin);
+  BKE_sequencer_cache_put(context, seq, cfra, SEQ_CACHE_STORE_PREPROCESSED, ibuf, cost, false);
+  return ibuf;
+}
+
+static ImBuf *seq_render_strip(const SeqRenderData *context,
+                               SeqRenderState *state,
+                               Sequence *seq,
+                               float cfra)
+{
+  ImBuf *ibuf = NULL;
+  bool use_preprocess = false;
+  bool is_proxy_image = false;
+
+  clock_t begin = seq_estimate_render_cost_begin();
+
+  ibuf = BKE_sequencer_cache_get(context, seq, cfra, SEQ_CACHE_STORE_PREPROCESSED, false);
+  if (ibuf != NULL) {
+    return ibuf;
+  }
+
+  ibuf = BKE_sequencer_cache_get(context, seq, cfra, SEQ_CACHE_STORE_RAW, false);
+  if (ibuf == NULL) {
+    ibuf = do_render_strip_uncached(context, state, seq, cfra, &is_proxy_image);
+  }
+
+  if (ibuf) {
+    use_preprocess = BKE_sequencer_input_have_to_preprocess(context, seq, cfra);
+    ibuf = seq_render_preprocess_ibuf(
+        context, seq, ibuf, cfra, begin, use_preprocess, is_proxy_image);
+  }
+
+  if (ibuf == NULL) {
+    ibuf = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+    sequencer_imbuf_assign_spaces(context->scene, ibuf);
+  }
+
+  return ibuf;
+}
+
+/*********************** strip stack rendering functions *************************/
+
+static bool seq_must_swap_input_in_blend_mode(Sequence *seq)
+{
+  bool swap_input = false;
+
+  /* bad hack, to fix crazy input ordering of
+   * those two effects */
+
+  if (ELEM(seq->blend_mode, SEQ_TYPE_ALPHAOVER, SEQ_TYPE_ALPHAUNDER, SEQ_TYPE_OVERDROP)) {
+    swap_input = true;
+  }
+
+  return swap_input;
+}
+
+static int seq_get_early_out_for_blend_mode(Sequence *seq)
+{
+  struct SeqEffectHandle sh = BKE_sequence_get_blend(seq);
+  float facf = seq->blend_opacity / 100.0f;
+  int early_out = sh.early_out(seq, facf, facf);
+
+  if (ELEM(early_out, EARLY_DO_EFFECT, EARLY_NO_INPUT)) {
+    return early_out;
+  }
+
+  if (seq_must_swap_input_in_blend_mode(seq)) {
+    if (early_out == EARLY_USE_INPUT_2) {
+      return EARLY_USE_INPUT_1;
+    }
+    if (early_out == EARLY_USE_INPUT_1) {
+      return EARLY_USE_INPUT_2;
+    }
+  }
+  return early_out;
+}
+
+static ImBuf *seq_render_strip_stack_apply_effect(
+    const SeqRenderData *context, Sequence *seq, float cfra, ImBuf *ibuf1, ImBuf *ibuf2)
+{
+  ImBuf *out;
+  struct SeqEffectHandle sh = BKE_sequence_get_blend(seq);
+  float facf = seq->blend_opacity / 100.0f;
+  int swap_input = seq_must_swap_input_in_blend_mode(seq);
+
+  if (swap_input) {
+    if (sh.multithreaded) {
+      out = BKE_sequencer_effect_execute_threaded(
+          &sh, context, seq, cfra, facf, facf, ibuf2, ibuf1, NULL);
+    }
+    else {
+      out = sh.execute(context, seq, cfra, facf, facf, ibuf2, ibuf1, NULL);
+    }
+  }
+  else {
+    if (sh.multithreaded) {
+      out = BKE_sequencer_effect_execute_threaded(
+          &sh, context, seq, cfra, facf, facf, ibuf1, ibuf2, NULL);
+    }
+    else {
+      out = sh.execute(context, seq, cfra, facf, facf, ibuf1, ibuf2, NULL);
+    }
+  }
+
+  return out;
+}
+
+static ImBuf *seq_render_strip_stack(const SeqRenderData *context,
+                                     SeqRenderState *state,
+                                     ListBase *seqbasep,
+                                     float cfra,
+                                     int chanshown)
+{
+  Sequence *seq_arr[MAXSEQ + 1];
+  int count;
+  int i;
+  ImBuf *out = NULL;
+  clock_t begin;
+
+  count = BKE_sequencer_get_shown_sequences(seqbasep, cfra, chanshown, (Sequence **)&seq_arr);
+
+  if (count == 0) {
+    return NULL;
+  }
+
+  for (i = count - 1; i >= 0; i--) {
+    int early_out;
+    Sequence *seq = seq_arr[i];
+
+    out = BKE_sequencer_cache_get(context, seq, cfra, SEQ_CACHE_STORE_COMPOSITE, false);
+
+    if (out) {
+      break;
+    }
+    if (seq->blend_mode == SEQ_BLEND_REPLACE) {
+      out = seq_render_strip(context, state, seq, cfra);
+      break;
+    }
+
+    early_out = seq_get_early_out_for_blend_mode(seq);
+
+    switch (early_out) {
+      case EARLY_NO_INPUT:
+      case EARLY_USE_INPUT_2:
+        out = seq_render_strip(context, state, seq, cfra);
+        break;
+      case EARLY_USE_INPUT_1:
+        if (i == 0) {
+          out = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+        }
+        break;
+      case EARLY_DO_EFFECT:
+        if (i == 0) {
+          begin = seq_estimate_render_cost_begin();
+
+          ImBuf *ibuf1 = IMB_allocImBuf(context->rectx, context->recty, 32, IB_rect);
+          ImBuf *ibuf2 = seq_render_strip(context, state, seq, cfra);
+
+          out = seq_render_strip_stack_apply_effect(context, seq, cfra, ibuf1, ibuf2);
+
+          float cost = seq_estimate_render_cost_end(context->scene, begin);
+          BKE_sequencer_cache_put(
+              context, seq_arr[i], cfra, SEQ_CACHE_STORE_COMPOSITE, out, cost, false);
+
+          IMB_freeImBuf(ibuf1);
+          IMB_freeImBuf(ibuf2);
+        }
+        break;
+    }
+    if (out) {
+      break;
+    }
+  }
+
+  i++;
+  for (; i < count; i++) {
+    begin = seq_estimate_render_cost_begin();
+    Sequence *seq = seq_arr[i];
+
+    if (seq_get_early_out_for_blend_mode(seq) == EARLY_DO_EFFECT) {
+      ImBuf *ibuf1 = out;
+      ImBuf *ibuf2 = seq_render_strip(context, state, seq, cfra);
+
+      out = seq_render_strip_stack_apply_effect(context, seq, cfra, ibuf1, ibuf2);
+
+      IMB_freeImBuf(ibuf1);
+      IMB_freeImBuf(ibuf2);
+    }
+
+    float cost = seq_estimate_render_cost_end(context->scene, begin);
+    BKE_sequencer_cache_put(
+        context, seq_arr[i], cfra, SEQ_CACHE_STORE_COMPOSITE, out, cost, false);
+  }
+
+  return out;
+}
+
+/*
+ * returned ImBuf is refed!
+ * you have to free after usage!
+ */
+
+ImBuf *BKE_sequencer_give_ibuf(const SeqRenderData *context, float cfra, int chanshown)
+{
+  Scene *scene = context->scene;
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  ListBase *seqbasep;
+
+  if (ed == NULL) {
+    return NULL;
+  }
+
+  if ((chanshown < 0) && !BLI_listbase_is_empty(&ed->metastack)) {
+    int count = BLI_listbase_count(&ed->metastack);
+    count = max_ii(count + chanshown, 0);
+    seqbasep = ((MetaStack *)BLI_findlink(&ed->metastack, count))->oldbasep;
+  }
+  else {
+    seqbasep = ed->seqbasep;
+  }
+
+  SeqRenderState state;
+  sequencer_state_init(&state);
+  ImBuf *out = NULL;
+  Sequence *seq_arr[MAXSEQ + 1];
+  int count;
+
+  count = BKE_sequencer_get_shown_sequences(seqbasep, cfra, chanshown, seq_arr);
+
+  if (count) {
+    out = BKE_sequencer_cache_get(
+        context, seq_arr[count - 1], cfra, SEQ_CACHE_STORE_FINAL_OUT, false);
+  }
+
+  BKE_sequencer_cache_free_temp_cache(context->scene, context->task_id, cfra);
+
+  clock_t begin = seq_estimate_render_cost_begin();
+  float cost = 0;
+
+  if (count && !out) {
+    BLI_mutex_lock(&seq_render_mutex);
+    out = seq_render_strip_stack(context, &state, seqbasep, cfra, chanshown);
+    cost = seq_estimate_render_cost_end(context->scene, begin);
+
+    if (context->is_prefetch_render) {
+      BKE_sequencer_cache_put(
+          context, seq_arr[count - 1], cfra, SEQ_CACHE_STORE_FINAL_OUT, out, cost, false);
+    }
+    else {
+      BKE_sequencer_cache_put_if_possible(
+          context, seq_arr[count - 1], cfra, SEQ_CACHE_STORE_FINAL_OUT, out, cost, false);
+    }
+    BLI_mutex_unlock(&seq_render_mutex);
+  }
+
+  BKE_sequencer_prefetch_start(context, cfra, cost);
+
+  return out;
+}
+
+ImBuf *BKE_sequencer_give_ibuf_seqbase(const SeqRenderData *context,
+                                       float cfra,
+                                       int chan_shown,
+                                       ListBase *seqbasep)
+{
+  SeqRenderState state;
+  sequencer_state_init(&state);
+
+  return seq_render_strip_stack(context, &state, seqbasep, cfra, chan_shown);
+}
+
+ImBuf *BKE_sequencer_give_ibuf_direct(const SeqRenderData *context, float cfra, Sequence *seq)
+{
+  SeqRenderState state;
+  sequencer_state_init(&state);
+
+  ImBuf *ibuf = seq_render_strip(context, &state, seq, cfra);
+
+  return ibuf;
+}
+
+/* check whether sequence cur depends on seq */
+bool BKE_sequence_check_depend(Sequence *seq, Sequence *cur)
+{
+  if (cur->seq1 == seq || cur->seq2 == seq || cur->seq3 == seq) {
+    return true;
+  }
+
+  /* sequences are not intersecting in time, assume no dependency exists between them */
+  if (cur->enddisp < seq->startdisp || cur->startdisp > seq->enddisp) {
+    return false;
+  }
+
+  /* checking sequence is below reference one, not dependent on it */
+  if (cur->machine < seq->machine) {
+    return false;
+  }
+
+  /* sequence is not blending with lower machines, no dependency here occurs
+   * check for non-effects only since effect could use lower machines as input
+   */
+  if ((cur->type & SEQ_TYPE_EFFECT) == 0 &&
+      ((cur->blend_mode == SEQ_BLEND_REPLACE) ||
+       (cur->blend_mode == SEQ_TYPE_CROSS && cur->blend_opacity == 100.0f))) {
+    return false;
+  }
+
+  return true;
+}
+
+static void sequence_do_invalidate_dependent(Scene *scene, Sequence *seq, ListBase *seqbase)
+{
+  Sequence *cur;
+
+  for (cur = seqbase->first; cur; cur = cur->next) {
+    if (cur == seq) {
+      continue;
+    }
+
+    if (BKE_sequence_check_depend(seq, cur)) {
+      /* Effect must be invalidated completely if they depend on invalidated seq. */
+      if ((cur->type & SEQ_TYPE_EFFECT) != 0) {
+        BKE_sequencer_cache_cleanup_sequence(scene, cur, seq, SEQ_CACHE_ALL_TYPES, false);
+      }
+      else {
+        /* In case of alpha over for example only invalidate composite image */
+        BKE_sequencer_cache_cleanup_sequence(
+            scene, cur, seq, SEQ_CACHE_STORE_COMPOSITE | SEQ_CACHE_STORE_FINAL_OUT, false);
+      }
+    }
+
+    if (cur->seqbase.first) {
+      sequence_do_invalidate_dependent(scene, seq, &cur->seqbase);
+    }
+  }
+}
+
+static void sequence_invalidate_cache(Scene *scene,
+                                      Sequence *seq,
+                                      bool invalidate_self,
+                                      int invalidate_types)
+{
+  Editing *ed = scene->ed;
+
+  if (invalidate_self) {
+    BKE_sequence_free_anim(seq);
+    BKE_sequencer_cache_cleanup_sequence(scene, seq, seq, invalidate_types, false);
+  }
+
+  if (seq->effectdata && seq->type == SEQ_TYPE_SPEED) {
+    BKE_sequence_effect_speed_rebuild_map(scene, seq, true);
+  }
+
+  sequence_do_invalidate_dependent(scene, seq, &ed->seqbase);
+  DEG_id_tag_update(&scene->id, ID_RECALC_SEQUENCER_STRIPS);
+  BKE_sequencer_prefetch_stop(scene);
+}
+
+void BKE_sequence_invalidate_cache_in_range(Scene *scene,
+                                            Sequence *seq,
+                                            Sequence *range_mask,
+                                            int invalidate_types)
+{
+  BKE_sequencer_cache_cleanup_sequence(scene, seq, range_mask, invalidate_types, true);
+}
+
+void BKE_sequence_invalidate_cache_raw(Scene *scene, Sequence *seq)
+{
+  sequence_invalidate_cache(scene, seq, true, SEQ_CACHE_ALL_TYPES);
+}
+
+void BKE_sequence_invalidate_cache_preprocessed(Scene *scene, Sequence *seq)
+{
+  sequence_invalidate_cache(scene,
+                            seq,
+                            true,
+                            SEQ_CACHE_STORE_PREPROCESSED | SEQ_CACHE_STORE_COMPOSITE |
+                                SEQ_CACHE_STORE_FINAL_OUT);
+}
+
+void BKE_sequence_invalidate_cache_composite(Scene *scene, Sequence *seq)
+{
+  if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SOUND_HD)) {
+    return;
+  }
+
+  sequence_invalidate_cache(
+      scene, seq, true, SEQ_CACHE_STORE_COMPOSITE | SEQ_CACHE_STORE_FINAL_OUT);
+}
+
+void BKE_sequence_invalidate_dependent(Scene *scene, Sequence *seq)
+{
+  if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SOUND_HD)) {
+    return;
+  }
+
+  sequence_invalidate_cache(
+      scene, seq, false, SEQ_CACHE_STORE_COMPOSITE | SEQ_CACHE_STORE_FINAL_OUT);
+}
+
+static void invalidate_scene_strips(Scene *scene, Scene *scene_target, ListBase *seqbase)
+{
+  for (Sequence *seq = seqbase->first; seq != NULL; seq = seq->next) {
+    if (seq->scene == scene_target) {
+      BKE_sequence_invalidate_cache_raw(scene, seq);
+    }
+
+    if (seq->seqbase.first != NULL) {
+      invalidate_scene_strips(scene, scene_target, &seq->seqbase);
+    }
+  }
+}
+
+void BKE_sequence_invalidate_scene_strips(Main *bmain, Scene *scene_target)
+{
+  for (Scene *scene = bmain->scenes.first; scene != NULL; scene = scene->id.next) {
+    if (scene->ed != NULL) {
+      invalidate_scene_strips(scene, scene_target, &scene->ed->seqbase);
+    }
+  }
+}
+
+static void invalidate_movieclip_strips(Scene *scene, MovieClip *clip_target, ListBase *seqbase)
+{
+  for (Sequence *seq = seqbase->first; seq != NULL; seq = seq->next) {
+    if (seq->clip == clip_target) {
+      BKE_sequence_invalidate_cache_raw(scene, seq);
+    }
+
+    if (seq->seqbase.first != NULL) {
+      invalidate_movieclip_strips(scene, clip_target, &seq->seqbase);
+    }
+  }
+}
+
+void BKE_sequence_invalidate_movieclip_strips(Main *bmain, MovieClip *clip_target)
+{
+  for (Scene *scene = bmain->scenes.first; scene != NULL; scene = scene->id.next) {
+    if (scene->ed != NULL) {
+      invalidate_movieclip_strips(scene, clip_target, &scene->ed->seqbase);
+    }
+  }
+}
+
+void BKE_sequencer_free_imbuf(Scene *scene, ListBase *seqbase, bool for_render)
+{
+  if (scene->ed == NULL) {
+    return;
+  }
+
+  Sequence *seq;
+
+  BKE_sequencer_cache_cleanup(scene);
+  BKE_sequencer_prefetch_stop(scene);
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    if (for_render && CFRA >= seq->startdisp && CFRA <= seq->enddisp) {
+      continue;
+    }
+
+    if (seq->strip) {
+      if (seq->type == SEQ_TYPE_MOVIE) {
+        BKE_sequence_free_anim(seq);
+      }
+      if (seq->type == SEQ_TYPE_SPEED) {
+        BKE_sequence_effect_speed_rebuild_map(scene, seq, true);
+      }
+    }
+    if (seq->type == SEQ_TYPE_META) {
+      BKE_sequencer_free_imbuf(scene, &seq->seqbase, for_render);
+    }
+    if (seq->type == SEQ_TYPE_SCENE) {
+      /* FIXME: recurs downwards,
+       * but do recurs protection somehow! */
+    }
+  }
+}
+
+static bool update_changed_seq_recurs(
+    Scene *scene, Sequence *seq, Sequence *changed_seq, int len_change, int ibuf_change)
+{
+  Sequence *subseq;
+  bool free_imbuf = false;
+
+  /* recurs downwards to see if this seq depends on the changed seq */
+
+  if (seq == NULL) {
+    return false;
+  }
+
+  if (seq == changed_seq) {
+    free_imbuf = true;
+  }
+
+  for (subseq = seq->seqbase.first; subseq; subseq = subseq->next) {
+    if (update_changed_seq_recurs(scene, subseq, changed_seq, len_change, ibuf_change)) {
+      free_imbuf = true;
+    }
+  }
+
+  if (seq->seq1) {
+    if (update_changed_seq_recurs(scene, seq->seq1, changed_seq, len_change, ibuf_change)) {
+      free_imbuf = true;
+    }
+  }
+  if (seq->seq2 && (seq->seq2 != seq->seq1)) {
+    if (update_changed_seq_recurs(scene, seq->seq2, changed_seq, len_change, ibuf_change)) {
+      free_imbuf = true;
+    }
+  }
+  if (seq->seq3 && (seq->seq3 != seq->seq1) && (seq->seq3 != seq->seq2)) {
+    if (update_changed_seq_recurs(scene, seq->seq3, changed_seq, len_change, ibuf_change)) {
+      free_imbuf = true;
+    }
+  }
+
+  if (free_imbuf) {
+    if (ibuf_change) {
+      if (seq->type == SEQ_TYPE_MOVIE) {
+        BKE_sequence_free_anim(seq);
+      }
+      else if (seq->type == SEQ_TYPE_SPEED) {
+        BKE_sequence_effect_speed_rebuild_map(scene, seq, true);
+      }
+    }
+
+    if (len_change) {
+      BKE_sequence_calc(scene, seq);
+    }
+  }
+
+  return free_imbuf;
+}
+
+void BKE_sequencer_update_changed_seq_and_deps(Scene *scene,
+                                               Sequence *changed_seq,
+                                               int len_change,
+                                               int ibuf_change)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  Sequence *seq;
+
+  if (ed == NULL) {
+    return;
+  }
+
+  for (seq = ed->seqbase.first; seq; seq = seq->next) {
+    update_changed_seq_recurs(scene, seq, changed_seq, len_change, ibuf_change);
+  }
+}
+
+/* seq funcs's for transforming internally
+ * notice the difference between start/end and left/right.
+ *
+ * left and right are the bounds at which the sequence is rendered,
+ * start and end are from the start and fixed length of the sequence.
+ */
+static int seq_tx_get_start(Sequence *seq)
+{
+  return seq->start;
+}
+static int seq_tx_get_end(Sequence *seq)
+{
+  return seq->start + seq->len;
+}
+
+int BKE_sequence_tx_get_final_left(Sequence *seq, bool metaclip)
+{
+  if (metaclip && seq->tmp) {
+    /* return the range clipped by the parents range */
+    return max_ii(BKE_sequence_tx_get_final_left(seq, false),
+                  BKE_sequence_tx_get_final_left((Sequence *)seq->tmp, true));
+  }
+
+  return (seq->start - seq->startstill) + seq->startofs;
+}
+int BKE_sequence_tx_get_final_right(Sequence *seq, bool metaclip)
+{
+  if (metaclip && seq->tmp) {
+    /* return the range clipped by the parents range */
+    return min_ii(BKE_sequence_tx_get_final_right(seq, false),
+                  BKE_sequence_tx_get_final_right((Sequence *)seq->tmp, true));
+  }
+
+  return ((seq->start + seq->len) + seq->endstill) - seq->endofs;
+}
+
+void BKE_sequence_tx_set_final_left(Sequence *seq, int val)
+{
+  if (val < (seq)->start) {
+    seq->startstill = abs(val - (seq)->start);
+    seq->startofs = 0;
+  }
+  else {
+    seq->startofs = abs(val - (seq)->start);
+    seq->startstill = 0;
+  }
+}
+
+void BKE_sequence_tx_set_final_right(Sequence *seq, int val)
+{
+  if (val > (seq)->start + (seq)->len) {
+    seq->endstill = abs(val - (seq->start + (seq)->len));
+    seq->endofs = 0;
+  }
+  else {
+    seq->endofs = abs(val - ((seq)->start + (seq)->len));
+    seq->endstill = 0;
+  }
+}
+
+/* used so we can do a quick check for single image seq
+ * since they work a bit differently to normal image seq's (during transform) */
+bool BKE_sequence_single_check(Sequence *seq)
+{
+  return ((seq->len == 1) &&
+          (seq->type == SEQ_TYPE_IMAGE ||
+           ((seq->type & SEQ_TYPE_EFFECT) && BKE_sequence_effect_get_num_inputs(seq->type) == 0)));
+}
+
+/* check if the selected seq's reference unselected seq's */
+bool BKE_sequence_base_isolated_sel_check(ListBase *seqbase)
+{
+  Sequence *seq;
+  /* is there more than 1 select */
+  bool ok = false;
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    if (seq->flag & SELECT) {
+      ok = true;
+      break;
+    }
+  }
+
+  if (ok == false) {
+    return false;
+  }
+
+  /* test relationships */
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    if ((seq->type & SEQ_TYPE_EFFECT) == 0) {
+      continue;
+    }
+
+    if (seq->flag & SELECT) {
+      if ((seq->seq1 && (seq->seq1->flag & SELECT) == 0) ||
+          (seq->seq2 && (seq->seq2->flag & SELECT) == 0) ||
+          (seq->seq3 && (seq->seq3->flag & SELECT) == 0)) {
+        return false;
+      }
+    }
+    else {
+      if ((seq->seq1 && (seq->seq1->flag & SELECT)) || (seq->seq2 && (seq->seq2->flag & SELECT)) ||
+          (seq->seq3 && (seq->seq3->flag & SELECT))) {
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+/* use to impose limits when dragging/extending - so impossible situations don't happen
+ * Cant use the SEQ_LEFTSEL and SEQ_LEFTSEL directly because the strip may be in a metastrip */
+void BKE_sequence_tx_handle_xlimits(Sequence *seq, int leftflag, int rightflag)
+{
+  if (leftflag) {
+    if (BKE_sequence_tx_get_final_left(seq, false) >=
+        BKE_sequence_tx_get_final_right(seq, false)) {
+      BKE_sequence_tx_set_final_left(seq, BKE_sequence_tx_get_final_right(seq, false) - 1);
+    }
+
+    if (BKE_sequence_single_check(seq) == 0) {
+      if (BKE_sequence_tx_get_final_left(seq, false) >= seq_tx_get_end(seq)) {
+        BKE_sequence_tx_set_final_left(seq, seq_tx_get_end(seq) - 1);
+      }
+
+      /* doesn't work now - TODO */
+#if 0
+      if (seq_tx_get_start(seq) >= seq_tx_get_final_right(seq, 0)) {
+        int ofs;
+        ofs = seq_tx_get_start(seq) - seq_tx_get_final_right(seq, 0);
+        seq->start -= ofs;
+        seq_tx_set_final_left(seq, seq_tx_get_final_left(seq, 0) + ofs);
+      }
+#endif
+    }
+  }
+
+  if (rightflag) {
+    if (BKE_sequence_tx_get_final_right(seq, false) <=
+        BKE_sequence_tx_get_final_left(seq, false)) {
+      BKE_sequence_tx_set_final_right(seq, BKE_sequence_tx_get_final_left(seq, false) + 1);
+    }
+
+    if (BKE_sequence_single_check(seq) == 0) {
+      if (BKE_sequence_tx_get_final_right(seq, false) <= seq_tx_get_start(seq)) {
+        BKE_sequence_tx_set_final_right(seq, seq_tx_get_start(seq) + 1);
+      }
+    }
+  }
+
+  /* sounds cannot be extended past their endpoints */
+  if (seq->type == SEQ_TYPE_SOUND_RAM) {
+    seq->startstill = 0;
+    seq->endstill = 0;
+  }
+}
+
+void BKE_sequence_single_fix(Sequence *seq)
+{
+  int left, start, offset;
+  if (!BKE_sequence_single_check(seq)) {
+    return;
+  }
+
+  /* make sure the image is always at the start since there is only one,
+   * adjusting its start should be ok */
+  left = BKE_sequence_tx_get_final_left(seq, false);
+  start = seq->start;
+  if (start != left) {
+    offset = left - start;
+    BKE_sequence_tx_set_final_left(seq, BKE_sequence_tx_get_final_left(seq, false) - offset);
+    BKE_sequence_tx_set_final_right(seq, BKE_sequence_tx_get_final_right(seq, false) - offset);
+    seq->start += offset;
+  }
+}
+
+bool BKE_sequence_tx_test(Sequence *seq)
+{
+  return !(seq->type & SEQ_TYPE_EFFECT) || (BKE_sequence_effect_get_num_inputs(seq->type) == 0);
+}
+
+/**
+ * Return \a true if given \a seq needs a complete cleanup of its cache when it is transformed.
+ *
+ * Some (effect) strip types need a complete recache of themselves when they are transformed,
+ * because they do not 'contain' anything and do not have any explicit relations to other strips.
+ */
+bool BKE_sequence_tx_fullupdate_test(Sequence *seq)
+{
+  return BKE_sequence_tx_test(seq) && ELEM(seq->type, SEQ_TYPE_ADJUSTMENT, SEQ_TYPE_MULTICAM);
+}
+
+static bool seq_overlap(Sequence *seq1, Sequence *seq2)
+{
+  return (seq1 != seq2 && seq1->machine == seq2->machine &&
+          ((seq1->enddisp <= seq2->startdisp) || (seq1->startdisp >= seq2->enddisp)) == 0);
+}
+
+bool BKE_sequence_test_overlap(ListBase *seqbasep, Sequence *test)
+{
+  Sequence *seq;
+
+  seq = seqbasep->first;
+  while (seq) {
+    if (seq_overlap(test, seq)) {
+      return true;
+    }
+
+    seq = seq->next;
+  }
+  return false;
+}
+
+void BKE_sequence_translate(Scene *evil_scene, Sequence *seq, int delta)
+{
+  if (delta == 0) {
+    return;
+  }
+
+  BKE_sequencer_offset_animdata(evil_scene, seq, delta);
+  seq->start += delta;
+
+  if (seq->type == SEQ_TYPE_META) {
+    Sequence *seq_child;
+    for (seq_child = seq->seqbase.first; seq_child; seq_child = seq_child->next) {
+      BKE_sequence_translate(evil_scene, seq_child, delta);
+    }
+  }
+
+  BKE_sequence_calc_disp(evil_scene, seq);
+}
+
+void BKE_sequence_sound_init(Scene *scene, Sequence *seq)
+{
+  if (seq->type == SEQ_TYPE_META) {
+    Sequence *seq_child;
+    for (seq_child = seq->seqbase.first; seq_child; seq_child = seq_child->next) {
+      BKE_sequence_sound_init(scene, seq_child);
+    }
+  }
+  else {
+    if (seq->sound) {
+      seq->scene_sound = BKE_sound_add_scene_sound_defaults(scene, seq);
+    }
+    if (seq->scene) {
+      seq->scene_sound = BKE_sound_scene_add_scene_sound_defaults(scene, seq);
+    }
+  }
+}
+
+const Sequence *BKE_sequencer_foreground_frame_get(const Scene *scene, int frame)
+{
+  const Editing *ed = scene->ed;
+  const Sequence *seq, *best_seq = NULL;
+  int best_machine = -1;
+
+  if (!ed) {
+    return NULL;
+  }
+
+  for (seq = ed->seqbasep->first; seq; seq = seq->next) {
+    if (seq->flag & SEQ_MUTE || seq->startdisp > frame || seq->enddisp <= frame) {
+      continue;
+    }
+    /* Only use strips that generate an image, not ones that combine
+     * other strips or apply some effect. */
+    if (ELEM(seq->type,
+             SEQ_TYPE_IMAGE,
+             SEQ_TYPE_META,
+             SEQ_TYPE_SCENE,
+             SEQ_TYPE_MOVIE,
+             SEQ_TYPE_COLOR,
+             SEQ_TYPE_TEXT)) {
+      if (seq->machine > best_machine) {
+        best_seq = seq;
+        best_machine = seq->machine;
+      }
+    }
+  }
+  return best_seq;
+}
+
+/* return 0 if there weren't enough space */
+bool BKE_sequence_base_shuffle_ex(ListBase *seqbasep,
+                                  Sequence *test,
+                                  Scene *evil_scene,
+                                  int channel_delta)
+{
+  const int orig_machine = test->machine;
+  BLI_assert(ELEM(channel_delta, -1, 1));
+
+  test->machine += channel_delta;
+  BKE_sequence_calc(evil_scene, test);
+  while (BKE_sequence_test_overlap(seqbasep, test)) {
+    if ((channel_delta > 0) ? (test->machine >= MAXSEQ) : (test->machine < 1)) {
+      break;
+    }
+
+    test->machine += channel_delta;
+    BKE_sequence_calc(
+        evil_scene,
+        test);  // XXX - I don't think this is needed since were only moving vertically, Campbell.
+  }
+
+  if ((test->machine < 1) || (test->machine > MAXSEQ)) {
+    /* Blender 2.4x would remove the strip.
+     * nicer to move it to the end */
+
+    Sequence *seq;
+    int new_frame = test->enddisp;
+
+    for (seq = seqbasep->first; seq; seq = seq->next) {
+      if (seq->machine == orig_machine) {
+        new_frame = max_ii(new_frame, seq->enddisp);
+      }
+    }
+
+    test->machine = orig_machine;
+    new_frame = new_frame + (test->start - test->startdisp); /* adjust by the startdisp */
+    BKE_sequence_translate(evil_scene, test, new_frame - test->start);
+
+    BKE_sequence_calc(evil_scene, test);
+    return false;
+  }
+
+  return true;
+}
+
+bool BKE_sequence_base_shuffle(ListBase *seqbasep, Sequence *test, Scene *evil_scene)
+{
+  return BKE_sequence_base_shuffle_ex(seqbasep, test, evil_scene, 1);
+}
+
+static int shuffle_seq_time_offset_test(ListBase *seqbasep, char dir)
+{
+  int offset = 0;
+  Sequence *seq, *seq_other;
+
+  for (seq = seqbasep->first; seq; seq = seq->next) {
+    if (seq->tmp) {
+      for (seq_other = seqbasep->first; seq_other; seq_other = seq_other->next) {
+        if (!seq_other->tmp && seq_overlap(seq, seq_other)) {
+          if (dir == 'L') {
+            offset = min_ii(offset, seq_other->startdisp - seq->enddisp);
+          }
+          else {
+            offset = max_ii(offset, seq_other->enddisp - seq->startdisp);
+          }
+        }
+      }
+    }
+  }
+  return offset;
+}
+
+static int shuffle_seq_time_offset(Scene *scene, ListBase *seqbasep, char dir)
+{
+  int ofs = 0;
+  int tot_ofs = 0;
+  Sequence *seq;
+  while ((ofs = shuffle_seq_time_offset_test(seqbasep, dir))) {
+    for (seq = seqbasep->first; seq; seq = seq->next) {
+      if (seq->tmp) {
+        /* seq_test_overlap only tests display values */
+        seq->startdisp += ofs;
+        seq->enddisp += ofs;
+      }
+    }
+
+    tot_ofs += ofs;
+  }
+
+  for (seq = seqbasep->first; seq; seq = seq->next) {
+    if (seq->tmp) {
+      BKE_sequence_calc_disp(scene, seq); /* corrects dummy startdisp/enddisp values */
+    }
+  }
+
+  return tot_ofs;
+}
+
+bool BKE_sequence_base_shuffle_time(ListBase *seqbasep,
+                                    Scene *evil_scene,
+                                    ListBase *markers,
+                                    const bool use_sync_markers)
+{
+  /* note: seq->tmp is used to tag strips to move */
+
+  Sequence *seq;
+
+  int offset_l = shuffle_seq_time_offset(evil_scene, seqbasep, 'L');
+  int offset_r = shuffle_seq_time_offset(evil_scene, seqbasep, 'R');
+  int offset = (-offset_l < offset_r) ? offset_l : offset_r;
+
+  if (offset) {
+    for (seq = seqbasep->first; seq; seq = seq->next) {
+      if (seq->tmp) {
+        BKE_sequence_translate(evil_scene, seq, offset);
+        seq->flag &= ~SEQ_OVERLAP;
+      }
+    }
+
+    if (use_sync_markers && !(evil_scene->toolsettings->lock_markers) && (markers != NULL)) {
+      TimeMarker *marker;
+      /* affect selected markers - it's unlikely that we will want to affect all in this way? */
+      for (marker = markers->first; marker; marker = marker->next) {
+        if (marker->flag & SELECT) {
+          marker->frame += offset;
+        }
+      }
+    }
+  }
+
+  return offset ? false : true;
+}
+
+/* Unlike _update_sound_ funcs, these ones take info from audaspace to update sequence length! */
+#ifdef WITH_AUDASPACE
+static bool sequencer_refresh_sound_length_recursive(Main *bmain, Scene *scene, ListBase *seqbase)
+{
+  Sequence *seq;
+  bool changed = false;
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    if (seq->type == SEQ_TYPE_META) {
+      if (sequencer_refresh_sound_length_recursive(bmain, scene, &seq->seqbase)) {
+        BKE_sequence_calc(scene, seq);
+        changed = true;
+      }
+    }
+    else if (seq->type == SEQ_TYPE_SOUND_RAM && seq->sound) {
+      const float length = BKE_sound_get_length(bmain, seq->sound);
+      int old = seq->len;
+      float fac;
+
+      seq->len = (int)ceil((double)length * FPS);
+      fac = (float)seq->len / (float)old;
+      old = seq->startofs;
+      seq->startofs *= fac;
+      seq->endofs *= fac;
+      seq->start += (old - seq->startofs); /* So that visual/"real" start frame does not change! */
+
+      BKE_sequence_calc(scene, seq);
+      changed = true;
+    }
+  }
+  return changed;
+}
+#endif
+
+void BKE_sequencer_refresh_sound_length(Main *bmain, Scene *scene)
+{
+#ifdef WITH_AUDASPACE
+  if (scene->ed) {
+    sequencer_refresh_sound_length_recursive(bmain, scene, &scene->ed->seqbase);
+  }
+#else
+  UNUSED_VARS(bmain, scene);
+#endif
+}
+
+void BKE_sequencer_update_sound_bounds_all(Scene *scene)
+{
+  Editing *ed = scene->ed;
+
+  if (ed) {
+    Sequence *seq;
+
+    for (seq = ed->seqbase.first; seq; seq = seq->next) {
+      if (seq->type == SEQ_TYPE_META) {
+        seq_update_sound_bounds_recursive(scene, seq);
+      }
+      else if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SCENE)) {
+        BKE_sequencer_update_sound_bounds(scene, seq);
+      }
+    }
+  }
+}
+
+void BKE_sequencer_update_sound_bounds(Scene *scene, Sequence *seq)
+{
+  if (seq->type == SEQ_TYPE_SCENE) {
+    if (seq->scene && seq->scene_sound) {
+      /* We have to take into account start frame of the sequence's scene! */
+      int startofs = seq->startofs + seq->anim_startofs + seq->scene->r.sfra;
+
+      BKE_sound_move_scene_sound(scene, seq->scene_sound, seq->startdisp, seq->enddisp, startofs);
+    }
+  }
+  else {
+    BKE_sound_move_scene_sound_defaults(scene, seq);
+  }
+  /* mute is set in seq_update_muting_recursive */
+}
+
+static void seq_update_muting_recursive(ListBase *seqbasep, Sequence *metaseq, int mute)
+{
+  Sequence *seq;
+  int seqmute;
+
+  /* for sound we go over full meta tree to update muted state,
+   * since sound is played outside of evaluating the imbufs, */
+  for (seq = seqbasep->first; seq; seq = seq->next) {
+    seqmute = (mute || (seq->flag & SEQ_MUTE));
+
+    if (seq->type == SEQ_TYPE_META) {
+      /* if this is the current meta sequence, unmute because
+       * all sequences above this were set to mute */
+      if (seq == metaseq) {
+        seqmute = 0;
+      }
+
+      seq_update_muting_recursive(&seq->seqbase, metaseq, seqmute);
+    }
+    else if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SCENE)) {
+      if (seq->scene_sound) {
+        BKE_sound_mute_scene_sound(seq->scene_sound, seqmute);
+      }
+    }
+  }
+}
+
+void BKE_sequencer_update_muting(Editing *ed)
+{
+  if (ed) {
+    /* mute all sounds up to current metastack list */
+    MetaStack *ms = ed->metastack.last;
+
+    if (ms) {
+      seq_update_muting_recursive(&ed->seqbase, ms->parseq, 1);
+    }
+    else {
+      seq_update_muting_recursive(&ed->seqbase, NULL, 0);
+    }
+  }
+}
+
+static void seq_update_sound_recursive(Scene *scene, ListBase *seqbasep, bSound *sound)
+{
+  Sequence *seq;
+
+  for (seq = seqbasep->first; seq; seq = seq->next) {
+    if (seq->type == SEQ_TYPE_META) {
+      seq_update_sound_recursive(scene, &seq->seqbase, sound);
+    }
+    else if (seq->type == SEQ_TYPE_SOUND_RAM) {
+      if (seq->scene_sound && sound == seq->sound) {
+        BKE_sound_update_scene_sound(seq->scene_sound, sound);
+      }
+    }
+  }
+}
+
+void BKE_sequencer_update_sound(Scene *scene, bSound *sound)
+{
+  if (scene->ed) {
+    seq_update_sound_recursive(scene, &scene->ed->seqbase, sound);
+  }
+}
+
+/* in cases where we done know the sequence's listbase */
+ListBase *BKE_sequence_seqbase(ListBase *seqbase, Sequence *seq)
+{
+  Sequence *iseq;
+  ListBase *lb = NULL;
+
+  for (iseq = seqbase->first; iseq; iseq = iseq->next) {
+    if (seq == iseq) {
+      return seqbase;
+    }
+    if (iseq->seqbase.first && (lb = BKE_sequence_seqbase(&iseq->seqbase, seq))) {
+      return lb;
+    }
+  }
+
+  return NULL;
+}
+
+Sequence *BKE_sequence_metastrip(ListBase *seqbase, Sequence *meta, Sequence *seq)
+{
+  Sequence *iseq;
+
+  for (iseq = seqbase->first; iseq; iseq = iseq->next) {
+    Sequence *rval;
+
+    if (seq == iseq) {
+      return meta;
+    }
+    if (iseq->seqbase.first && (rval = BKE_sequence_metastrip(&iseq->seqbase, iseq, seq))) {
+      return rval;
+    }
+  }
+
+  return NULL;
+}
+
+int BKE_sequence_swap(Sequence *seq_a, Sequence *seq_b, const char **error_str)
+{
+  char name[sizeof(seq_a->name)];
+
+  if (seq_a->len != seq_b->len) {
+    *error_str = N_("Strips must be the same length");
+    return 0;
+  }
+
+  /* type checking, could be more advanced but disallow sound vs non-sound copy */
+  if (seq_a->type != seq_b->type) {
+    if (seq_a->type == SEQ_TYPE_SOUND_RAM || seq_b->type == SEQ_TYPE_SOUND_RAM) {
+      *error_str = N_("Strips were not compatible");
+      return 0;
+    }
+
+    /* disallow effects to swap with non-effects strips */
+    if ((seq_a->type & SEQ_TYPE_EFFECT) != (seq_b->type & SEQ_TYPE_EFFECT)) {
+      *error_str = N_("Strips were not compatible");
+      return 0;
+    }
+
+    if ((seq_a->type & SEQ_TYPE_EFFECT) && (seq_b->type & SEQ_TYPE_EFFECT)) {
+      if (BKE_sequence_effect_get_num_inputs(seq_a->type) !=
+          BKE_sequence_effect_get_num_inputs(seq_b->type)) {
+        *error_str = N_("Strips must have the same number of inputs");
+        return 0;
+      }
+    }
+  }
+
+  SWAP(Sequence, *seq_a, *seq_b);
+
+  /* swap back names so animation fcurves don't get swapped */
+  BLI_strncpy(name, seq_a->name + 2, sizeof(name));
+  BLI_strncpy(seq_a->name + 2, seq_b->name + 2, sizeof(seq_b->name) - 2);
+  BLI_strncpy(seq_b->name + 2, name, sizeof(seq_b->name) - 2);
+
+  /* swap back opacity, and overlay mode */
+  SWAP(int, seq_a->blend_mode, seq_b->blend_mode);
+  SWAP(float, seq_a->blend_opacity, seq_b->blend_opacity);
+
+  SWAP(Sequence *, seq_a->prev, seq_b->prev);
+  SWAP(Sequence *, seq_a->next, seq_b->next);
+  SWAP(int, seq_a->start, seq_b->start);
+  SWAP(int, seq_a->startofs, seq_b->startofs);
+  SWAP(int, seq_a->endofs, seq_b->endofs);
+  SWAP(int, seq_a->startstill, seq_b->startstill);
+  SWAP(int, seq_a->endstill, seq_b->endstill);
+  SWAP(int, seq_a->machine, seq_b->machine);
+  SWAP(int, seq_a->startdisp, seq_b->startdisp);
+  SWAP(int, seq_a->enddisp, seq_b->enddisp);
+
+  return 1;
+}
+
+/* r_prefix + [" + escaped_name + "] + \0 */
+#define SEQ_RNAPATH_MAXSTR ((30 + 2 + (SEQ_NAME_MAXSTR * 2) + 2) + 1)
+
+static size_t sequencer_rna_path_prefix(char str[SEQ_RNAPATH_MAXSTR], const char *name)
+{
+  char name_esc[SEQ_NAME_MAXSTR * 2];
+
+  BLI_strescape(name_esc, name, sizeof(name_esc));
+  return BLI_snprintf_rlen(
+      str, SEQ_RNAPATH_MAXSTR, "sequence_editor.sequences_all[\"%s\"]", name_esc);
+}
+
+/* XXX - hackish function needed for transforming strips! TODO - have some better solution */
+void BKE_sequencer_offset_animdata(Scene *scene, Sequence *seq, int ofs)
+{
+  char str[SEQ_RNAPATH_MAXSTR];
+  size_t str_len;
+  FCurve *fcu;
+
+  if (scene->adt == NULL || ofs == 0 || scene->adt->action == NULL) {
+    return;
+  }
+
+  str_len = sequencer_rna_path_prefix(str, seq->name + 2);
+
+  for (fcu = scene->adt->action->curves.first; fcu; fcu = fcu->next) {
+    if (STREQLEN(fcu->rna_path, str, str_len)) {
+      unsigned int i;
+      if (fcu->bezt) {
+        for (i = 0; i < fcu->totvert; i++) {
+          BezTriple *bezt = &fcu->bezt[i];
+          bezt->vec[0][0] += ofs;
+          bezt->vec[1][0] += ofs;
+          bezt->vec[2][0] += ofs;
+        }
+      }
+      if (fcu->fpt) {
+        for (i = 0; i < fcu->totvert; i++) {
+          FPoint *fpt = &fcu->fpt[i];
+          fpt->vec[0] += ofs;
+        }
+      }
+    }
+  }
+
+  DEG_id_tag_update(&scene->adt->action->id, ID_RECALC_ANIMATION);
+}
+
+void BKE_sequencer_dupe_animdata(Scene *scene, const char *name_src, const char *name_dst)
+{
+  char str_from[SEQ_RNAPATH_MAXSTR];
+  size_t str_from_len;
+  FCurve *fcu;
+  FCurve *fcu_last;
+  FCurve *fcu_cpy;
+  ListBase lb = {NULL, NULL};
+
+  if (scene->adt == NULL || scene->adt->action == NULL) {
+    return;
+  }
+
+  str_from_len = sequencer_rna_path_prefix(str_from, name_src);
+
+  fcu_last = scene->adt->action->curves.last;
+
+  for (fcu = scene->adt->action->curves.first; fcu && fcu->prev != fcu_last; fcu = fcu->next) {
+    if (STREQLEN(fcu->rna_path, str_from, str_from_len)) {
+      fcu_cpy = BKE_fcurve_copy(fcu);
+      BLI_addtail(&lb, fcu_cpy);
+    }
+  }
+
+  /* notice validate is 0, keep this because the seq may not be added to the scene yet */
+  BKE_animdata_fix_paths_rename(
+      &scene->id, scene->adt, NULL, "sequence_editor.sequences_all", name_src, name_dst, 0, 0, 0);
+
+  /* add the original fcurves back */
+  BLI_movelisttolist(&scene->adt->action->curves, &lb);
+}
+
+/* XXX - hackish function needed to remove all fcurves belonging to a sequencer strip */
+static void seq_free_animdata(Scene *scene, Sequence *seq)
+{
+  char str[SEQ_RNAPATH_MAXSTR];
+  size_t str_len;
+  FCurve *fcu;
+
+  if (scene->adt == NULL || scene->adt->action == NULL) {
+    return;
+  }
+
+  str_len = sequencer_rna_path_prefix(str, seq->name + 2);
+
+  fcu = scene->adt->action->curves.first;
+
+  while (fcu) {
+    if (STREQLEN(fcu->rna_path, str, str_len)) {
+      FCurve *next_fcu = fcu->next;
+
+      BLI_remlink(&scene->adt->action->curves, fcu);
+      BKE_fcurve_free(fcu);
+
+      fcu = next_fcu;
+    }
+    else {
+      fcu = fcu->next;
+    }
+  }
+}
+
+#undef SEQ_RNAPATH_MAXSTR
+
+Sequence *BKE_sequence_get_by_name(ListBase *seqbase, const char *name, bool recursive)
+{
+  Sequence *iseq = NULL;
+  Sequence *rseq = NULL;
+
+  for (iseq = seqbase->first; iseq; iseq = iseq->next) {
+    if (STREQ(name, iseq->name + 2)) {
+      return iseq;
+    }
+    if (recursive && (iseq->seqbase.first) &&
+        (rseq = BKE_sequence_get_by_name(&iseq->seqbase, name, 1))) {
+      return rseq;
+    }
+  }
+
+  return NULL;
+}
+
+/**
+ * Only use as last resort when the StripElem is available but no the Sequence.
+ * (needed for RNA)
+ */
+Sequence *BKE_sequencer_from_elem(ListBase *seqbase, StripElem *se)
+{
+  Sequence *iseq;
+
+  for (iseq = seqbase->first; iseq; iseq = iseq->next) {
+    Sequence *seq_found;
+    if ((iseq->strip && iseq->strip->stripdata) &&
+        (ARRAY_HAS_ITEM(se, iseq->strip->stripdata, iseq->len))) {
+      break;
+    }
+    if ((seq_found = BKE_sequencer_from_elem(&iseq->seqbase, se))) {
+      iseq = seq_found;
+      break;
+    }
+  }
+
+  return iseq;
+}
+
+Sequence *BKE_sequencer_active_get(Scene *scene)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+
+  if (ed == NULL) {
+    return NULL;
+  }
+
+  return ed->act_seq;
+}
+
+void BKE_sequencer_active_set(Scene *scene, Sequence *seq)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+
+  if (ed == NULL) {
+    return;
+  }
+
+  ed->act_seq = seq;
+}
+
+int BKE_sequencer_active_get_pair(Scene *scene, Sequence **seq_act, Sequence **seq_other)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+
+  *seq_act = BKE_sequencer_active_get(scene);
+
+  if (*seq_act == NULL) {
+    return 0;
+  }
+
+  Sequence *seq;
+
+  *seq_other = NULL;
+
+  for (seq = ed->seqbasep->first; seq; seq = seq->next) {
+    if (seq->flag & SELECT && (seq != (*seq_act))) {
+      if (*seq_other) {
+        return 0;
+      }
+
+      *seq_other = seq;
+    }
+  }
+
+  return (*seq_other != NULL);
+}
+
+Mask *BKE_sequencer_mask_get(Scene *scene)
+{
+  Sequence *seq_act = BKE_sequencer_active_get(scene);
+
+  if (seq_act && seq_act->type == SEQ_TYPE_MASK) {
+    return seq_act->mask;
+  }
+
+  return NULL;
+}
+
+/* api like funcs for adding */
+
+static void seq_load_apply(Main *bmain, Scene *scene, Sequence *seq, SeqLoadInfo *seq_load)
+{
+  if (seq) {
+    BLI_strncpy_utf8(seq->name + 2, seq_load->name, sizeof(seq->name) - 2);
+    BLI_utf8_invalid_strip(seq->name + 2, strlen(seq->name + 2));
+    BKE_sequence_base_unique_name_recursive(&scene->ed->seqbase, seq);
+
+    if (seq_load->flag & SEQ_LOAD_FRAME_ADVANCE) {
+      seq_load->start_frame += (seq->enddisp - seq->startdisp);
+    }
+
+    if (seq_load->flag & SEQ_LOAD_REPLACE_SEL) {
+      seq_load->flag |= SELECT;
+      BKE_sequencer_active_set(scene, seq);
+    }
+
+    if (seq_load->flag & SEQ_LOAD_SOUND_MONO) {
+      seq->sound->flags |= SOUND_FLAGS_MONO;
+      BKE_sound_load(bmain, seq->sound);
+    }
+
+    if (seq_load->flag & SEQ_LOAD_SOUND_CACHE) {
+      if (seq->sound) {
+        seq->sound->flags |= SOUND_FLAGS_CACHING;
+      }
+    }
+
+    seq_load->tot_success++;
+  }
+  else {
+    seq_load->tot_error++;
+  }
+}
+
+static Strip *seq_strip_alloc(int type)
+{
+  Strip *strip = MEM_callocN(sizeof(Strip), "strip");
+
+  if (ELEM(type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SOUND_HD) == 0) {
+    strip->transform = MEM_callocN(sizeof(struct StripTransform), "StripTransform");
+    strip->crop = MEM_callocN(sizeof(struct StripCrop), "StripCrop");
+  }
+
+  strip->us = 1;
+  return strip;
+}
+
+Sequence *BKE_sequence_alloc(ListBase *lb, int cfra, int machine, int type)
+{
+  Sequence *seq;
+
+  seq = MEM_callocN(sizeof(Sequence), "addseq");
+  BLI_addtail(lb, seq);
+
+  *((short *)seq->name) = ID_SEQ;
+  seq->name[2] = 0;
+
+  seq->flag = SELECT;
+  seq->start = cfra;
+  seq->machine = machine;
+  seq->sat = 1.0;
+  seq->mul = 1.0;
+  seq->blend_opacity = 100.0;
+  seq->volume = 1.0f;
+  seq->pitch = 1.0f;
+  seq->scene_sound = NULL;
+  seq->type = type;
+
+  seq->strip = seq_strip_alloc(type);
+  seq->stereo3d_format = MEM_callocN(sizeof(Stereo3dFormat), "Sequence Stereo Format");
+  seq->cache_flag = SEQ_CACHE_STORE_RAW | SEQ_CACHE_STORE_PREPROCESSED | SEQ_CACHE_STORE_COMPOSITE;
+
+  BKE_sequence_session_uuid_generate(seq);
+
+  return seq;
+}
+
+void BKE_sequence_session_uuid_generate(struct Sequence *sequence)
+{
+  sequence->runtime.session_uuid = BLI_session_uuid_generate();
+}
+
+void BKE_sequence_alpha_mode_from_extension(Sequence *seq)
+{
+  if (seq->strip && seq->strip->stripdata) {
+    const char *filename = seq->strip->stripdata->name;
+    seq->alpha_mode = BKE_image_alpha_mode_from_extension_ex(filename);
+  }
+}
+
+void BKE_sequence_init_colorspace(Sequence *seq)
+{
+  if (seq->strip && seq->strip->stripdata) {
+    char name[FILE_MAX];
+    ImBuf *ibuf;
+
+    BLI_join_dirfile(name, sizeof(name), seq->strip->dir, seq->strip->stripdata->name);
+    BLI_path_abs(name, BKE_main_blendfile_path_from_global());
+
+    /* initialize input color space */
+    if (seq->type == SEQ_TYPE_IMAGE) {
+      ibuf = IMB_loadiffname(
+          name, IB_test | IB_alphamode_detect, seq->strip->colorspace_settings.name);
+
+      /* byte images are default to straight alpha, however sequencer
+       * works in premul space, so mark strip to be premultiplied first
+       */
+      seq->alpha_mode = SEQ_ALPHA_STRAIGHT;
+      if (ibuf) {
+        if (ibuf->flags & IB_alphamode_premul) {
+          seq->alpha_mode = IMA_ALPHA_PREMUL;
+        }
+
+        IMB_freeImBuf(ibuf);
+      }
+    }
+  }
+}
+
+float BKE_sequence_get_fps(Scene *scene, Sequence *seq)
+{
+  switch (seq->type) {
+    case SEQ_TYPE_MOVIE: {
+      seq_open_anim_file(scene, seq, true);
+      if (BLI_listbase_is_empty(&seq->anims)) {
+        return 0.0f;
+      }
+      StripAnim *strip_anim = seq->anims.first;
+      if (strip_anim->anim == NULL) {
+        return 0.0f;
+      }
+      short frs_sec;
+      float frs_sec_base;
+      if (IMB_anim_get_fps(strip_anim->anim, &frs_sec, &frs_sec_base, true)) {
+        return (float)frs_sec / frs_sec_base;
+      }
+      break;
+    }
+    case SEQ_TYPE_MOVIECLIP:
+      if (seq->clip != NULL) {
+        return BKE_movieclip_get_fps(seq->clip);
+      }
+      break;
+    case SEQ_TYPE_SCENE:
+      if (seq->scene != NULL) {
+        return (float)seq->scene->r.frs_sec / seq->scene->r.frs_sec_base;
+      }
+      break;
+  }
+  return 0.0f;
+}
+
+/* NOTE: this function doesn't fill in image names */
+Sequence *BKE_sequencer_add_image_strip(bContext *C, ListBase *seqbasep, SeqLoadInfo *seq_load)
+{
+  Scene *scene = CTX_data_scene(C); /* only for active seq */
+  Sequence *seq;
+  Strip *strip;
+
+  seq = BKE_sequence_alloc(seqbasep, seq_load->start_frame, seq_load->channel, SEQ_TYPE_IMAGE);
+  seq->blend_mode = SEQ_TYPE_CROSS; /* so alpha adjustment fade to the strip below */
+
+  /* basic defaults */
+  seq->len = seq_load->len ? seq_load->len : 1;
+
+  strip = seq->strip;
+  strip->stripdata = MEM_callocN(seq->len * sizeof(StripElem), "stripelem");
+  BLI_strncpy(strip->dir, seq_load->path, sizeof(strip->dir));
+
+  if (seq_load->stereo3d_format) {
+    *seq->stereo3d_format = *seq_load->stereo3d_format;
+  }
+
+  seq->views_format = seq_load->views_format;
+  seq->flag |= seq_load->flag & SEQ_USE_VIEWS;
+
+  seq_load_apply(CTX_data_main(C), scene, seq, seq_load);
+  BKE_sequence_invalidate_cache_composite(scene, seq);
+
+  return seq;
+}
+
+#ifdef WITH_AUDASPACE
+Sequence *BKE_sequencer_add_sound_strip(bContext *C, ListBase *seqbasep, SeqLoadInfo *seq_load)
+{
+  Main *bmain = CTX_data_main(C);
+  Scene *scene = CTX_data_scene(C); /* only for sound */
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  bSound *sound;
+
+  Sequence *seq; /* generic strip vars */
+  Strip *strip;
+  StripElem *se;
+
+  sound = BKE_sound_new_file(bmain, seq_load->path); /* handles relative paths */
+
+  SoundInfo info;
+  if (!BKE_sound_info_get(bmain, sound, &info)) {
+    BKE_id_free(bmain, sound);
+    return NULL;
+  }
+
+  if (info.specs.channels == SOUND_CHANNELS_INVALID) {
+    BKE_id_free(bmain, sound);
+    return NULL;
+  }
+
+  seq = BKE_sequence_alloc(seqbasep, seq_load->start_frame, seq_load->channel, SEQ_TYPE_SOUND_RAM);
+  seq->sound = sound;
+  BLI_strncpy(seq->name + 2, "Sound", SEQ_NAME_MAXSTR - 2);
+  BKE_sequence_base_unique_name_recursive(&scene->ed->seqbase, seq);
+
+  /* basic defaults */
+  /* We add a very small negative offset here, because
+   * ceil(132.0) == 133.0, not nice with videos, see T47135. */
+  seq->len = (int)ceil((double)info.length * FPS - 1e-4);
+  strip = seq->strip;
+
+  /* we only need 1 element to store the filename */
+  strip->stripdata = se = MEM_callocN(sizeof(StripElem), "stripelem");
+
+  BLI_split_dirfile(seq_load->path, strip->dir, se->name, sizeof(strip->dir), sizeof(se->name));
+
+  seq->scene_sound = NULL;
+
+  BKE_sequence_calc_disp(scene, seq);
+
+  /* last active name */
+  BLI_strncpy(ed->act_sounddir, strip->dir, FILE_MAXDIR);
+
+  seq_load_apply(bmain, scene, seq, seq_load);
+
+  /* TODO(sergey): Shall we tag here or in the operator? */
+  DEG_relations_tag_update(bmain);
+
+  return seq;
+}
+#else   // WITH_AUDASPACE
+Sequence *BKE_sequencer_add_sound_strip(bContext *C, ListBase *seqbasep, SeqLoadInfo *seq_load)
+{
+  (void)C;
+  (void)seqbasep;
+  (void)seq_load;
+  return NULL;
+}
+#endif  // WITH_AUDASPACE
+
+static void seq_anim_add_suffix(Scene *scene, struct anim *anim, const int view_id)
+{
+  const char *suffix = BKE_scene_multiview_view_id_suffix_get(&scene->r, view_id);
+  IMB_suffix_anim(anim, suffix);
+}
+
+Sequence *BKE_sequencer_add_movie_strip(bContext *C, ListBase *seqbasep, SeqLoadInfo *seq_load)
+{
+  Main *bmain = CTX_data_main(C);
+  Scene *scene = CTX_data_scene(C); /* only for sound */
+  char path[sizeof(seq_load->path)];
+
+  Sequence *seq; /* generic strip vars */
+  Strip *strip;
+  StripElem *se;
+  char colorspace[64] = "\0"; /* MAX_COLORSPACE_NAME */
+  bool is_multiview_loaded = false;
+  const bool is_multiview = (seq_load->flag & SEQ_USE_VIEWS) != 0;
+  const int totfiles = seq_num_files(scene, seq_load->views_format, is_multiview);
+  struct anim **anim_arr;
+  int i;
+
+  BLI_strncpy(path, seq_load->path, sizeof(path));
+  BLI_path_abs(path, BKE_main_blendfile_path(bmain));
+
+  anim_arr = MEM_callocN(sizeof(struct anim *) * totfiles, "Video files");
+
+  if (is_multiview && (seq_load->views_format == R_IMF_VIEWS_INDIVIDUAL)) {
+    char prefix[FILE_MAX];
+    const char *ext = NULL;
+    size_t j = 0;
+
+    BKE_scene_multiview_view_prefix_get(scene, path, prefix, &ext);
+
+    if (prefix[0] != '\0') {
+      for (i = 0; i < totfiles; i++) {
+        char str[FILE_MAX];
+
+        seq_multiview_name(scene, i, prefix, ext, str, FILE_MAX);
+        anim_arr[j] = openanim(str, IB_rect, 0, colorspace);
+
+        if (anim_arr[j]) {
+          seq_anim_add_suffix(scene, anim_arr[j], i);
+          j++;
+        }
+      }
+
+      if (j == 0) {
+        MEM_freeN(anim_arr);
+        return NULL;
+      }
+      is_multiview_loaded = true;
+    }
+  }
+
+  if (is_multiview_loaded == false) {
+    anim_arr[0] = openanim(path, IB_rect, 0, colorspace);
+
+    if (anim_arr[0] == NULL) {
+      MEM_freeN(anim_arr);
+      return NULL;
+    }
+  }
+
+  if (seq_load->flag & SEQ_LOAD_MOVIE_SOUND) {
+    seq_load->channel++;
+  }
+  seq = BKE_sequence_alloc(seqbasep, seq_load->start_frame, seq_load->channel, SEQ_TYPE_MOVIE);
+
+  /* multiview settings */
+  if (seq_load->stereo3d_format) {
+    *seq->stereo3d_format = *seq_load->stereo3d_format;
+    seq->views_format = seq_load->views_format;
+  }
+  seq->flag |= seq_load->flag & SEQ_USE_VIEWS;
+
+  seq->type = SEQ_TYPE_MOVIE;
+  seq->blend_mode = SEQ_TYPE_CROSS; /* so alpha adjustment fade to the strip below */
+
+  for (i = 0; i < totfiles; i++) {
+    if (anim_arr[i]) {
+      StripAnim *sanim = MEM_mallocN(sizeof(StripAnim), "Strip Anim");
+      BLI_addtail(&seq->anims, sanim);
+      sanim->anim = anim_arr[i];
+    }
+    else {
+      break;
+    }
+  }
+
+  IMB_anim_load_metadata(anim_arr[0]);
+
+  seq->anim_preseek = IMB_anim_get_preseek(anim_arr[0]);
+  BLI_strncpy(seq->name + 2, "Movie", SEQ_NAME_MAXSTR - 2);
+  BKE_sequence_base_unique_name_recursive(&scene->ed->seqbase, seq);
+
+  /* adjust scene's frame rate settings to match */
+  if (seq_load->flag & SEQ_LOAD_SYNC_FPS) {
+    IMB_anim_get_fps(anim_arr[0], &scene->r.frs_sec, &scene->r.frs_sec_base, true);
+  }
+
+  /* basic defaults */
+  seq->len = IMB_anim_get_duration(anim_arr[0], IMB_TC_RECORD_RUN);
+  strip = seq->strip;
+
+  BLI_strncpy(seq->strip->colorspace_settings.name,
+              colorspace,
+              sizeof(seq->strip->colorspace_settings.name));
+
+  /* we only need 1 element for MOVIE strips */
+  strip->stripdata = se = MEM_callocN(sizeof(StripElem), "stripelem");
+
+  BLI_split_dirfile(seq_load->path, strip->dir, se->name, sizeof(strip->dir), sizeof(se->name));
+
+  BKE_sequence_calc_disp(scene, seq);
+
+  if (seq_load->name[0] == '\0') {
+    BLI_strncpy(seq_load->name, se->name, sizeof(seq_load->name));
+  }
+
+  if (seq_load->flag & SEQ_LOAD_MOVIE_SOUND) {
+    int start_frame_back = seq_load->start_frame;
+    seq_load->channel--;
+    seq_load->seq_sound = BKE_sequencer_add_sound_strip(C, seqbasep, seq_load);
+    seq_load->start_frame = start_frame_back;
+  }
+
+  /* can be NULL */
+  seq_load_apply(CTX_data_main(C), scene, seq, seq_load);
+  BKE_sequence_invalidate_cache_composite(scene, seq);
+
+  MEM_freeN(anim_arr);
+  return seq;
+}
+
+static Sequence *seq_dupli(const Scene *scene_src,
+                           Scene *scene_dst,
+                           ListBase *new_seq_list,
+                           Sequence *seq,
+                           int dupe_flag,
+                           const int flag)
+{
+  Sequence *seqn = MEM_dupallocN(seq);
+
+  if ((flag & LIB_ID_CREATE_NO_MAIN) == 0) {
+    BKE_sequence_session_uuid_generate(seq);
+  }
+
+  seq->tmp = seqn;
+  seqn->strip = MEM_dupallocN(seq->strip);
+
+  seqn->stereo3d_format = MEM_dupallocN(seq->stereo3d_format);
+
+  /* XXX: add F-Curve duplication stuff? */
+
+  if (seq->strip->crop) {
+    seqn->strip->crop = MEM_dupallocN(seq->strip->crop);
+  }
+
+  if (seq->strip->transform) {
+    seqn->strip->transform = MEM_dupallocN(seq->strip->transform);
+  }
+
+  if (seq->strip->proxy) {
+    seqn->strip->proxy = MEM_dupallocN(seq->strip->proxy);
+    seqn->strip->proxy->anim = NULL;
+  }
+
+  if (seq->prop) {
+    seqn->prop = IDP_CopyProperty_ex(seq->prop, flag);
+  }
+
+  if (seqn->modifiers.first) {
+    BLI_listbase_clear(&seqn->modifiers);
+
+    BKE_sequence_modifier_list_copy(seqn, seq);
+  }
+
+  if (seq->type == SEQ_TYPE_META) {
+    seqn->strip->stripdata = NULL;
+
+    BLI_listbase_clear(&seqn->seqbase);
+    /* WATCH OUT!!! - This metastrip is not recursively duplicated here - do this after!!! */
+    /* - seq_dupli_recursive(&seq->seqbase, &seqn->seqbase);*/
+  }
+  else if (seq->type == SEQ_TYPE_SCENE) {
+    seqn->strip->stripdata = NULL;
+    if (seq->scene_sound) {
+      seqn->scene_sound = BKE_sound_scene_add_scene_sound_defaults(scene_dst, seqn);
+    }
+  }
+  else if (seq->type == SEQ_TYPE_MOVIECLIP) {
+    /* avoid assert */
+  }
+  else if (seq->type == SEQ_TYPE_MASK) {
+    /* avoid assert */
+  }
+  else if (seq->type == SEQ_TYPE_MOVIE) {
+    seqn->strip->stripdata = MEM_dupallocN(seq->strip->stripdata);
+    BLI_listbase_clear(&seqn->anims);
+  }
+  else if (seq->type == SEQ_TYPE_SOUND_RAM) {
+    seqn->strip->stripdata = MEM_dupallocN(seq->strip->stripdata);
+    seqn->scene_sound = NULL;
+    if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
+      id_us_plus((ID *)seqn->sound);
+    }
+  }
+  else if (seq->type == SEQ_TYPE_IMAGE) {
+    seqn->strip->stripdata = MEM_dupallocN(seq->strip->stripdata);
+  }
+  else if (seq->type & SEQ_TYPE_EFFECT) {
+    struct SeqEffectHandle sh;
+    sh = BKE_sequence_get_effect(seq);
+    if (sh.copy) {
+      sh.copy(seqn, seq, flag);
+    }
+
+    seqn->strip->stripdata = NULL;
+  }
+  else {
+    /* sequence type not handled in duplicate! Expect a crash now... */
+    BLI_assert(0);
+  }
+
+  /* When using SEQ_DUPE_UNIQUE_NAME, it is mandatory to add new sequences in relevant container
+   * (scene or meta's one), *before* checking for unique names. Otherwise the meta's list is empty
+   * and hence we miss all seqs in that meta that have already been duplicated (see T55668).
+   * Note that unique name check itself could be done at a later step in calling code, once all
+   * seqs have bee duplicated (that was first, simpler solution), but then handling of animation
+   * data will be broken (see T60194). */
+  if (new_seq_list != NULL) {
+    BLI_addtail(new_seq_list, seqn);
+  }
+
+  if (scene_src == scene_dst) {
+    if (dupe_flag & SEQ_DUPE_UNIQUE_NAME) {
+      BKE_sequence_base_unique_name_recursive(&scene_dst->ed->seqbase, seqn);
+    }
+
+    if (dupe_flag & SEQ_DUPE_ANIM) {
+      BKE_sequencer_dupe_animdata(scene_dst, seq->name + 2, seqn->name + 2);
+    }
+  }
+
+  return seqn;
+}
+
+static void seq_new_fix_links_recursive(Sequence *seq)
+{
+  SequenceModifierData *smd;
+
+  if (seq->type & SEQ_TYPE_EFFECT) {
+    if (seq->seq1 && seq->seq1->tmp) {
+      seq->seq1 = seq->seq1->tmp;
+    }
+    if (seq->seq2 && seq->seq2->tmp) {
+      seq->seq2 = seq->seq2->tmp;
+    }
+    if (seq->seq3 && seq->seq3->tmp) {
+      seq->seq3 = seq->seq3->tmp;
+    }
+  }
+  else if (seq->type == SEQ_TYPE_META) {
+    Sequence *seqn;
+    for (seqn = seq->seqbase.first; seqn; seqn = seqn->next) {
+      seq_new_fix_links_recursive(seqn);
+    }
+  }
+
+  for (smd = seq->modifiers.first; smd; smd = smd->next) {
+    if (smd->mask_sequence && smd->mask_sequence->tmp) {
+      smd->mask_sequence = smd->mask_sequence->tmp;
+    }
+  }
+}
+
+static Sequence *sequence_dupli_recursive_do(const Scene *scene_src,
+                                             Scene *scene_dst,
+                                             ListBase *new_seq_list,
+                                             Sequence *seq,
+                                             const int dupe_flag)
+{
+  Sequence *seqn;
+
+  seq->tmp = NULL;
+  seqn = seq_dupli(scene_src, scene_dst, new_seq_list, seq, dupe_flag, 0);
+  if (seq->type == SEQ_TYPE_META) {
+    Sequence *s;
+    for (s = seq->seqbase.first; s; s = s->next) {
+      sequence_dupli_recursive_do(scene_src, scene_dst, &seqn->seqbase, s, dupe_flag);
+    }
+  }
+
+  return seqn;
+}
+
+Sequence *BKE_sequence_dupli_recursive(
+    const Scene *scene_src, Scene *scene_dst, ListBase *new_seq_list, Sequence *seq, int dupe_flag)
+{
+  Sequence *seqn = sequence_dupli_recursive_do(scene_src, scene_dst, new_seq_list, seq, dupe_flag);
+
+  /* This does not need to be in recursive call itself, since it is already recursive... */
+  seq_new_fix_links_recursive(seqn);
+
+  return seqn;
+}
+
+void BKE_sequence_base_dupli_recursive(const Scene *scene_src,
+                                       Scene *scene_dst,
+                                       ListBase *nseqbase,
+                                       const ListBase *seqbase,
+                                       int dupe_flag,
+                                       const int flag)
+{
+  Sequence *seq;
+  Sequence *seqn = NULL;
+  Sequence *last_seq = BKE_sequencer_active_get((Scene *)scene_src);
+  /* always include meta's strips */
+  int dupe_flag_recursive = dupe_flag | SEQ_DUPE_ALL | SEQ_DUPE_IS_RECURSIVE_CALL;
+
+  for (seq = seqbase->first; seq; seq = seq->next) {
+    seq->tmp = NULL;
+    if ((seq->flag & SELECT) || (dupe_flag & SEQ_DUPE_ALL)) {
+      seqn = seq_dupli(scene_src, scene_dst, nseqbase, seq, dupe_flag, flag);
+      if (seqn) { /*should never fail */
+        if (dupe_flag & SEQ_DUPE_CONTEXT) {
+          seq->flag &= ~SEQ_ALLSEL;
+          seqn->flag &= ~(SEQ_LEFTSEL + SEQ_RIGHTSEL + SEQ_LOCK);
+        }
+
+        if (seq->type == SEQ_TYPE_META) {
+          BKE_sequence_base_dupli_recursive(
+              scene_src, scene_dst, &seqn->seqbase, &seq->seqbase, dupe_flag_recursive, flag);
+        }
+
+        if (dupe_flag & SEQ_DUPE_CONTEXT) {
+          if (seq == last_seq) {
+            BKE_sequencer_active_set(scene_dst, seqn);
+          }
+        }
+      }
+    }
+  }
+
+  /* Fix modifier links recursively from the top level only, when all sequences have been
+   * copied. */
+  if (dupe_flag & SEQ_DUPE_IS_RECURSIVE_CALL) {
+    return;
+  }
+
+  /* fix modifier linking */
+  for (seq = nseqbase->first; seq; seq = seq->next) {
+    seq_new_fix_links_recursive(seq);
+  }
+}
+
+/* called on draw, needs to be fast,
+ * we could cache and use a flag if we want to make checks for file paths resolving for eg. */
+bool BKE_sequence_is_valid_check(Sequence *seq)
+{
+  switch (seq->type) {
+    case SEQ_TYPE_MASK:
+      return (seq->mask != NULL);
+    case SEQ_TYPE_MOVIECLIP:
+      return (seq->clip != NULL);
+    case SEQ_TYPE_SCENE:
+      return (seq->scene != NULL);
+    case SEQ_TYPE_SOUND_RAM:
+      return (seq->sound != NULL);
+  }
+
+  return true;
+}
+
+int BKE_sequencer_find_next_prev_edit(Scene *scene,
+                                      int cfra,
+                                      const short side,
+                                      const bool do_skip_mute,
+                                      const bool do_center,
+                                      const bool do_unselected)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  Sequence *seq;
+
+  int dist, best_dist, best_frame = cfra;
+  int seq_frames[2], seq_frames_tot;
+
+  /* In case where both is passed,
+   * frame just finds the nearest end while frame_left the nearest start. */
+
+  best_dist = MAXFRAME * 2;
+
+  if (ed == NULL) {
+    return cfra;
+  }
+
+  for (seq = ed->seqbasep->first; seq; seq = seq->next) {
+    int i;
+
+    if (do_skip_mute && (seq->flag & SEQ_MUTE)) {
+      continue;
+    }
+
+    if (do_unselected && (seq->flag & SELECT)) {
+      continue;
+    }
+
+    if (do_center) {
+      seq_frames[0] = (seq->startdisp + seq->enddisp) / 2;
+      seq_frames_tot = 1;
+    }
+    else {
+      seq_frames[0] = seq->startdisp;
+      seq_frames[1] = seq->enddisp;
+
+      seq_frames_tot = 2;
+    }
+
+    for (i = 0; i < seq_frames_tot; i++) {
+      const int seq_frame = seq_frames[i];
+
+      dist = MAXFRAME * 2;
+
+      switch (side) {
+        case SEQ_SIDE_LEFT:
+          if (seq_frame < cfra) {
+            dist = cfra - seq_frame;
+          }
+          break;
+        case SEQ_SIDE_RIGHT:
+          if (seq_frame > cfra) {
+            dist = seq_frame - cfra;
+          }
+          break;
+        case SEQ_SIDE_BOTH:
+          dist = abs(seq_frame - cfra);
+          break;
+      }
+
+      if (dist < best_dist) {
+        best_frame = seq_frame;
+        best_dist = dist;
+      }
+    }
+  }
+
+  return best_frame;
+}
+
+static void sequencer_all_free_anim_ibufs(ListBase *seqbase, int cfra)
+{
+  for (Sequence *seq = seqbase->first; seq != NULL; seq = seq->next) {
+    if (seq->enddisp < cfra || seq->startdisp > cfra) {
+      BKE_sequence_free_anim(seq);
+    }
+    if (seq->type == SEQ_TYPE_META) {
+      sequencer_all_free_anim_ibufs(&seq->seqbase, cfra);
+    }
+  }
+}
+
+void BKE_sequencer_all_free_anim_ibufs(Scene *scene, int cfra)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  if (ed == NULL) {
+    return;
+  }
+  sequencer_all_free_anim_ibufs(&ed->seqbase, cfra);
+  BKE_sequencer_cache_cleanup(scene);
+}
+
+static bool sequencer_seq_generates_image(Sequence *seq)
+{
+  switch (seq->type) {
+    case SEQ_TYPE_IMAGE:
+    case SEQ_TYPE_SCENE:
+    case SEQ_TYPE_MOVIE:
+    case SEQ_TYPE_MOVIECLIP:
+    case SEQ_TYPE_MASK:
+    case SEQ_TYPE_COLOR:
+    case SEQ_TYPE_TEXT:
+      return true;
+  }
+  return false;
+}
+
+static Sequence *sequencer_check_scene_recursion(Scene *scene, ListBase *seqbase)
+{
+  LISTBASE_FOREACH (Sequence *, seq, seqbase) {
+    if (seq->type == SEQ_TYPE_SCENE && seq->scene == scene) {
+      return seq;
+    }
+
+    if (seq->type == SEQ_TYPE_META && sequencer_check_scene_recursion(scene, &seq->seqbase)) {
+      return seq;
+    }
+  }
+
+  return NULL;
+}
+
+bool BKE_sequencer_check_scene_recursion(Scene *scene, ReportList *reports)
+{
+  Editing *ed = BKE_sequencer_editing_get(scene, false);
+  if (ed == NULL) {
+    return false;
+  }
+
+  Sequence *recursive_seq = sequencer_check_scene_recursion(scene, &ed->seqbase);
+
+  if (recursive_seq != NULL) {
+    BKE_reportf(reports,
+                RPT_WARNING,
+                "Recursion detected in video sequencer. Strip %s at frame %d will not be rendered",
+                recursive_seq->name + 2,
+                recursive_seq->startdisp);
+
+    LISTBASE_FOREACH (Sequence *, seq, &ed->seqbase) {
+      if (seq->type != SEQ_TYPE_SCENE && sequencer_seq_generates_image(seq)) {
+        /* There are other strips to render, so render them. */
+        return false;
+      }
+    }
+    /* No other strips to render - cancel operator. */
+    return true;
+  }
+
+  return false;
+}
+
+/* Check if "seq_main" (indirectly) uses strip "seq". */
+bool BKE_sequencer_render_loop_check(Sequence *seq_main, Sequence *seq)
+{
+  if (seq_main == seq) {
+    return true;
+  }
+
+  if ((seq_main->seq1 && BKE_sequencer_render_loop_check(seq_main->seq1, seq)) ||
+      (seq_main->seq2 && BKE_sequencer_render_loop_check(seq_main->seq2, seq)) ||
+      (seq_main->seq3 && BKE_sequencer_render_loop_check(seq_main->seq3, seq))) {
+    return true;
+  }
+
+  SequenceModifierData *smd;
+  for (smd = seq_main->modifiers.first; smd; smd = smd->next) {
+    if (smd->mask_sequence && BKE_sequencer_render_loop_check(smd->mask_sequence, seq)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+static void sequencer_flag_users_for_removal(Scene *scene, ListBase *seqbase, Sequence *seq)
+{
+  LISTBASE_FOREACH (Sequence *, user_seq, seqbase) {
+    /* Look in metas for usage of seq. */
+    if (user_seq->type == SEQ_TYPE_META) {
+      sequencer_flag_users_for_removal(scene, &user_seq->seqbase, seq);
+    }
+
+    /* Clear seq from modifiers. */
+    SequenceModifierData *smd;
+    for (smd = user_seq->modifiers.first; smd; smd = smd->next) {
+      if (smd->mask_sequence == seq) {
+        smd->mask_sequence = NULL;
+      }
+    }
+
+    /* Remove effects, that use seq. */
+    if ((user_seq->seq1 && user_seq->seq1 == seq) || (user_seq->seq2 && user_seq->seq2 == seq) ||
+        (user_seq->seq3 && user_seq->seq3 == seq)) {
+      user_seq->flag |= SEQ_FLAG_DELETE;
+      /* Strips can be used as mask even if not in same seqbase. */
+      sequencer_flag_users_for_removal(scene, &scene->ed->seqbase, user_seq);
+    }
+  }
+}
+
+/* Flag seq and its users (effects) for removal. */
+void BKE_sequencer_flag_for_removal(Scene *scene, ListBase *seqbase, Sequence *seq)
+{
+  if (seq == NULL || (seq->flag & SEQ_FLAG_DELETE) != 0) {
+    return;
+  }
+
+  /* Flag and remove meta children. */
+  if (seq->type == SEQ_TYPE_META) {
+    LISTBASE_FOREACH (Sequence *, meta_child, &seq->seqbase) {
+      BKE_sequencer_flag_for_removal(scene, &seq->seqbase, meta_child);
+    }
+  }
+
+  seq->flag |= SEQ_FLAG_DELETE;
+  sequencer_flag_users_for_removal(scene, seqbase, seq);
+}
+
+/* Remove all flagged sequences, return true if sequence is removed. */
+void BKE_sequencer_remove_flagged_sequences(Scene *scene, ListBase *seqbase)
+{
+  LISTBASE_FOREACH_MUTABLE (Sequence *, seq, seqbase) {
+    if (seq->flag & SEQ_FLAG_DELETE) {
+      if (seq->type == SEQ_TYPE_META) {
+        BKE_sequencer_remove_flagged_sequences(scene, &seq->seqbase);
+      }
+      BLI_remlink(seqbase, seq);
+      BKE_sequence_free(scene, seq, true);
+    }
+  }
+}
+
+void BKE_sequencer_check_uuids_unique_and_report(const Scene *scene)
+{
+  if (scene->ed == NULL) {
+    return;
+  }
+
+  struct GSet *used_uuids = BLI_gset_new(
+      BLI_session_uuid_ghash_hash, BLI_session_uuid_ghash_compare, "sequencer used uuids");
+
+  const Sequence *sequence;
+  SEQ_ALL_BEGIN (scene->ed, sequence) {
+    const SessionUUID *session_uuid = &sequence->runtime.session_uuid;
+    if (!BLI_session_uuid_is_generated(session_uuid)) {
+      printf("Sequence %s does not have UUID generated.\n", sequence->name);
+      continue;
+    }
+
+    if (BLI_gset_lookup(used_uuids, session_uuid) != NULL) {
+      printf("Sequence %s has duplicate UUID generated.\n", sequence->name);
+      continue;
+    }
+
+    BLI_gset_insert(used_uuids, (void *)session_uuid);
+  }
+  SEQ_ALL_END;
+
+  BLI_gset_free(used_uuids, NULL);
+}