Cleanup: Fix comment style and check if they are valid or make sense.

1 files changed, 296 insertions, 321 deletions

diff --git a/source/blender/editors/space_sequencer/sequencer_edit.c b/source/blender/editors/space_sequencer/sequencer_edit.c
index 3d9de1f567c..c2ffb2f55c2 100644
--- a/source/blender/editors/space_sequencer/sequencer_edit.c
+++ b/source/blender/editors/space_sequencer/sequencer_edit.c
@@ -52,7 +52,7 @@
 #include "RNA_define.h"
 #include "RNA_enum_types.h"
 
-/* for menu/popup icons etc etc*/
+/* For menu, popup, icons, etc. */
 
 #include "ED_anim_api.h"
 #include "ED_numinput.h"
@@ -67,11 +67,11 @@
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_build.h"
 
-/* own include */
+/* Own include. */
 #include "sequencer_intern.h"
 
 /* XXX */
-/* RNA Enums, used in multiple files */
+/* RNA Enums, used in multiple files. */
 EnumPropertyItem sequencer_prop_effect_types[] = {
     {SEQ_TYPE_CROSS, "CROSS", 0, "Crossfade", "Crossfade effect strip type"},
     {SEQ_TYPE_ADD, "ADD", 0, "Add", "Add effect strip type"},
@@ -94,8 +94,6 @@ EnumPropertyItem sequencer_prop_effect_types[] = {
     {0, NULL, 0, NULL, NULL},
 };
 
-/* mute operator */
-
 #define SEQ_SIDE_MOUSE -1
 
 EnumPropertyItem prop_side_types[] = {
@@ -144,7 +142,7 @@ static void proxy_freejob(void *pjv)
   MEM_freeN(pj);
 }
 
-/* only this runs inside thread */
+/* Only this runs inside thread. */
 static void proxy_startjob(void *pjv, short *stop, short *do_update, float *progress)
 {
   ProxyJob *pj = pjv;
@@ -291,7 +289,7 @@ static int mouse_frame_side(View2D *v2d, short mouse_x, int frame)
   mval[0] = mouse_x;
   mval[1] = 0;
 
-  /* choose the side based on which side of the playhead the mouse is on */
+  /* Choose the side based on which side of the playhead the mouse is on. */
   UI_view2d_region_to_view(v2d, mval[0], mval[1], &mouseloc[0], &mouseloc[1]);
 
   return mouseloc[0] > frame ? SEQ_SIDE_RIGHT : SEQ_SIDE_LEFT;
@@ -299,7 +297,7 @@ static int mouse_frame_side(View2D *v2d, short mouse_x, int frame)
 
 Sequence *find_neighboring_sequence(Scene *scene, Sequence *test, int lr, int sel)
 {
-  /* sel - 0==unselected, 1==selected, -1==done care*/
+  /* sel: 0==unselected, 1==selected, -1==don't care. */
   Sequence *seq;
   Editing *ed = BKE_sequencer_editing_get(scene, false);
 
@@ -334,7 +332,7 @@ Sequence *find_neighboring_sequence(Scene *scene, Sequence *test, int lr, int se
 
 static Sequence *find_next_prev_sequence(Scene *scene, Sequence *test, int lr, int sel)
 {
-  /* sel - 0==unselected, 1==selected, -1==done care*/
+  /* sel: 0==unselected, 1==selected, -1==don't care. */
   Sequence *seq, *best_seq = NULL;
   Editing *ed = BKE_sequencer_editing_get(scene, false);
 
@@ -375,7 +373,7 @@ static Sequence *find_next_prev_sequence(Scene *scene, Sequence *test, int lr, i
     }
     seq = seq->next;
   }
-  return best_seq; /* can be null */
+  return best_seq; /* Can be null. */
 }
 
 Sequence *find_nearest_seq(Scene *scene, View2D *v2d, int *hand, const int mval[2])
@@ -400,22 +398,21 @@ Sequence *find_nearest_seq(Scene *scene, View2D *v2d, int *hand, const int mval[
 
   while (seq) {
     if (seq->machine == (int)y) {
-      /* check for both normal strips, and strips that have been flipped horizontally */
+      /* Check for both normal strips, and strips that have been flipped horizontally. */
       if (((seq->startdisp < seq->enddisp) && (seq->startdisp <= x && seq->enddisp >= x)) ||
           ((seq->startdisp > seq->enddisp) && (seq->startdisp >= x && seq->enddisp <= x))) {
         if (BKE_sequence_tx_test(seq)) {
 
-          /* clamp handles to defined size in pixel space */
-
+          /* Clamp handles to defined size in pixel space. */
           handsize = 2.0f * sequence_handle_size_get_clamped(seq, pixelx);
           displen = (float)abs(seq->startdisp - seq->enddisp);
 
-          /* don't even try to grab the handles of small strips */
+          /* Don't even try to grab the handles of small strips. */
           if (displen / pixelx > 16) {
+
             /* Set the max value to handle to 1/3 of the total len when its
              * less than 28. This is important because otherwise selecting
              * handles happens even when you click in the middle. */
-
             if ((displen / 3) < 30 * pixelx) {
               handsize = displen / 3;
             }
@@ -510,7 +507,6 @@ void recurs_sel_seq(Sequence *seqm)
 
 bool ED_space_sequencer_maskedit_mask_poll(bContext *C)
 {
-  /* in this case both funcs are the same, for clip editor not */
   return ED_space_sequencer_maskedit_poll(C);
 }
 
@@ -535,7 +531,7 @@ bool ED_space_sequencer_maskedit_poll(bContext *C)
   return false;
 }
 
-/* are we displaying the seq output (not channels or histogram)*/
+/* Are we displaying the seq output (not channels or histogram). */
 bool ED_space_sequencer_check_show_imbuf(SpaceSeq *sseq)
 {
   return (ELEM(sseq->view, SEQ_VIEW_PREVIEW, SEQ_VIEW_SEQUENCE_PREVIEW) &&
@@ -589,8 +585,8 @@ int seq_effect_find_selected(Scene *scene,
     }
   }
 
-  /* make sequence selection a little bit more intuitive
-   * for 3 strips: the last-strip should be sequence3 */
+  /* Make sequence selection a little bit more intuitive
+   * for 3 strips: the last-strip should be seq3. */
   if (seq3 != NULL && seq2 != NULL) {
     Sequence *tmp = seq2;
     seq2 = seq3;
@@ -600,7 +596,7 @@ int seq_effect_find_selected(Scene *scene,
   switch (BKE_sequence_effect_get_num_inputs(type)) {
     case 0:
       *r_selseq1 = *r_selseq2 = *r_selseq3 = NULL;
-      return 1; /* success */
+      return 1; /* Success. */
     case 1:
       if (seq2 == NULL) {
         *r_error_str = N_("At least one selected sequence strip is needed");
@@ -640,8 +636,8 @@ static Sequence *del_seq_find_replace_recurs(Scene *scene, Sequence *seq)
 {
   Sequence *seq1, *seq2, *seq3;
 
-  /* try to find a replacement input sequence, and flag for later deletion if
-   * no replacement can be found */
+  /* Try to find a replacement input sequence, and flag for later deletion if
+   * no replacement can be found. */
 
   if (!seq) {
     return NULL;
@@ -650,13 +646,13 @@ static Sequence *del_seq_find_replace_recurs(Scene *scene, Sequence *seq)
     return ((seq->flag & SELECT) ? NULL : seq);
   }
   else if (!(seq->flag & SELECT)) {
-    /* try to find replacement for effect inputs */
+    /* Try to find replacement for effect inputs. */
     seq1 = del_seq_find_replace_recurs(scene, seq->seq1);
     seq2 = del_seq_find_replace_recurs(scene, seq->seq2);
     seq3 = del_seq_find_replace_recurs(scene, seq->seq3);
 
     if (seq1 == seq->seq1 && seq2 == seq->seq2 && seq3 == seq->seq3) {
-      /* pass */
+      /* Pass. */
     }
     else if (seq1 || seq2 || seq3) {
       seq->seq1 = (seq1) ? seq1 : (seq2) ? seq2 : seq3;
@@ -666,7 +662,7 @@ static Sequence *del_seq_find_replace_recurs(Scene *scene, Sequence *seq)
       BKE_sequencer_update_changed_seq_and_deps(scene, seq, 1, 1);
     }
     else {
-      seq->flag |= SELECT; /* mark for delete */
+      seq->flag |= SELECT; /* Mark for delete. */
     }
   }
 
@@ -740,7 +736,7 @@ static Sequence *split_seq_hard(
   /* Unlike soft-split, it's important to use the same value for both strips. */
   const bool is_end_exact = ((seq->start + seq->len) == split_frame);
 
-  /* backup values */
+  /* Backup values. */
   ts.start = seq->start;
   ts.machine = seq->machine;
   ts.startstill = seq->startstill;
@@ -753,21 +749,19 @@ static Sequence *split_seq_hard(
   ts.anim_endofs = seq->anim_endofs;
   ts.len = seq->len;
 
-  /* First Strip! */
-  /* strips with extended stillfames before */
-
-  /* Precaution, needed because the length saved on-disk may not match the length saved in the
-   * blend file, or our code may have minor differences reading file length between versions.
-   * This causes hard-split to fail, see: T47862 */
   if (seq->type != SEQ_TYPE_META) {
+    /* Precaution, needed because the length saved on-disk may not match the length saved in the
+     * blend file, or our code may have minor differences reading file length between versions.
+     * This causes hard-split to fail, see: T47862. */
     BKE_sequence_reload_new_file(bmain, scene, seq, true);
     BKE_sequence_calc(scene, seq);
   }
 
+  /* First Strip. */
   /* Important to offset the start when 'split_frame == seq->start'
    * because we need at least one frame of content after start/end still have clipped it. */
   if ((seq->startstill) && (split_frame <= seq->start)) {
-    /* don't do funny things with METAs ... */
+    /* Don't do funny things with METAs. */
     if (seq->type == SEQ_TYPE_META) {
       skip_dup = true;
       seq->startstill = seq->start - split_frame;
@@ -779,18 +773,18 @@ static Sequence *split_seq_hard(
       seq->endstill = 0;
     }
   }
-  /* normal strip */
+  /* Normal strip. */
   else if ((is_end_exact == false) &&
            ((split_frame >= seq->start) && (split_frame <= (seq->start + seq->len)))) {
     seq->endofs = 0;
     seq->endstill = 0;
     seq->anim_endofs += (seq->start + seq->len) - split_frame;
   }
-  /* strips with extended stillframes after */
+  /* Strips with extended stillframes. */
   else if ((is_end_exact == true) ||
            (((seq->start + seq->len) < split_frame) && (seq->endstill))) {
     seq->endstill -= seq->enddisp - split_frame;
-    /* don't do funny things with METAs ... */
+    /* Don't do funny things with METAs. */
     if (seq->type == SEQ_TYPE_META) {
       skip_dup = true;
     }
@@ -800,7 +794,7 @@ static Sequence *split_seq_hard(
   BKE_sequence_calc(scene, seq);
 
   if (!skip_dup) {
-    /* Duplicate AFTER the first change */
+    /* Duplicate AFTER the first change. */
     seqn = BKE_sequence_dupli_recursive(
         scene, scene, new_seq_list, seq, SEQ_DUPE_UNIQUE_NAME | SEQ_DUPE_ANIM);
   }
@@ -808,12 +802,11 @@ static Sequence *split_seq_hard(
   if (seqn) {
     seqn->flag |= SELECT;
 
-    /* Important not to re-assign this (unlike soft-split) */
 #if 0
     is_end_exact = ((seqn->start + seqn->len) == split_frame);
 #endif
-    /* Second Strip! */
-    /* strips with extended stillframes before */
+    /* Second Strip. */
+    /* strips with extended stillframes. */
     if ((seqn->startstill) && (split_frame == seqn->start + 1)) {
       seqn->start = ts.start;
       seqn->startstill = ts.start - split_frame;
@@ -821,7 +814,7 @@ static Sequence *split_seq_hard(
       seqn->endstill = ts.endstill;
     }
 
-    /* normal strip */
+    /* Normal strip. */
     else if ((is_end_exact == false) &&
              ((split_frame >= seqn->start) && (split_frame <= (seqn->start + seqn->len)))) {
       seqn->start = split_frame;
@@ -833,7 +826,7 @@ static Sequence *split_seq_hard(
       seqn->endstill = ts.endstill;
     }
 
-    /* strips with extended stillframes after */
+    /* Strips with extended stillframes after. */
     else if ((is_end_exact == true) ||
              (((seqn->start + seqn->len) < split_frame) && (seqn->endstill))) {
       seqn->start = split_frame;
@@ -858,7 +851,7 @@ static Sequence *split_seq_soft(
 
   bool is_end_exact = ((seq->start + seq->len) == split_frame);
 
-  /* backup values */
+  /* Backup values. */
   ts.start = seq->start;
   ts.machine = seq->machine;
   ts.startstill = seq->startstill;
@@ -871,9 +864,8 @@ static Sequence *split_seq_soft(
   ts.anim_endofs = seq->anim_endofs;
   ts.len = seq->len;
 
-  /* First Strip! */
-  /* strips with extended stillfames before */
-
+  /* First Strip. */
+  /* Strips with extended stillfames. */
   /* Important to offset the start when 'split_frame == seq->start'
    * because we need at least one frame of content after start/end still have clipped it. */
   if ((seq->startstill) && (split_frame <= seq->start)) {
@@ -889,16 +881,16 @@ static Sequence *split_seq_soft(
       seq->endstill = 0;
     }
   }
-  /* normal strip */
+  /* Normal strip. */
   else if ((is_end_exact == false) && (split_frame >= seq->start) &&
            (split_frame <= (seq->start + seq->len))) {
     seq->endofs = (seq->start + seq->len) - split_frame;
   }
-  /* strips with extended stillframes after */
+  /* Strips with extended stillframes. */
   else if ((is_end_exact == true) ||
            (((seq->start + seq->len) < split_frame) && (seq->endstill))) {
     seq->endstill -= seq->enddisp - split_frame;
-    /* don't do funny things with METAs ... */
+    /* Don't do funny things with METAs. */
     if (seq->type == SEQ_TYPE_META) {
       skip_dup = true;
     }
@@ -907,7 +899,7 @@ static Sequence *split_seq_soft(
   BKE_sequence_calc(scene, seq);
 
   if (!skip_dup) {
-    /* Duplicate AFTER the first change */
+    /* Duplicate AFTER the first change. */
     seqn = BKE_sequence_dupli_recursive(
         scene, scene, new_seq_list, seq, SEQ_DUPE_UNIQUE_NAME | SEQ_DUPE_ANIM);
   }
@@ -917,8 +909,8 @@ static Sequence *split_seq_soft(
 
     is_end_exact = ((seqn->start + seqn->len) == split_frame);
 
-    /* Second Strip! */
-    /* strips with extended stillframes before */
+    /* Second Strip. */
+    /* Strips with extended stillframes. */
     if ((seqn->startstill) && (split_frame == seqn->start + 1)) {
       seqn->start = ts.start;
       seqn->startstill = ts.start - split_frame;
@@ -926,7 +918,7 @@ static Sequence *split_seq_soft(
       seqn->endstill = ts.endstill;
     }
 
-    /* normal strip */
+    /* Normal strip. */
     else if ((is_end_exact == false) && (split_frame >= seqn->start) &&
              (split_frame <= (seqn->start + seqn->len))) {
       seqn->startstill = 0;
@@ -935,7 +927,7 @@ static Sequence *split_seq_soft(
       seqn->endstill = ts.endstill;
     }
 
-    /* strips with extended stillframes after */
+    /* Strips with extended stillframes. */
     else if ((is_end_exact == true) ||
              (((seqn->start + seqn->len) < split_frame) && (seqn->endstill))) {
       seqn->start = split_frame - ts.len + 1;
@@ -949,12 +941,12 @@ static Sequence *split_seq_soft(
   return seqn;
 }
 
-/* like duplicate, but only duplicate and split overlapping strips,
+/* Like duplicate, but only duplicate and split overlapping strips,
  * strips to the left of the split_frame are ignored and strips to the right
- * are moved to the end of slist
- * we have to work on the same slist (not using a separate list), since
+ * are moved to the end of slist.
+ * We have to work on the same slist (not using a separate list), since
  * otherwise dupli_seq can't check for duplicate names properly and
- * may generate strips with the same name (which will mess up animdata)
+ * may generate strips with the same name which will mess up animdata.
  */
 
 static bool split_seq_list(
@@ -973,7 +965,7 @@ static bool split_seq_list(
   seq = slist->first;
 
   while (seq && seq != seq_first_new) {
-    seq_next_iter = seq->next; /* we need this because we may remove seq */
+    seq_next_iter = seq->next; /* We need this because we may remove seq. */
     seq->tmp = NULL;
     if (use_cursor_position) {
       if (seq->machine == channel && seq->startdisp < split_frame && seq->enddisp > split_frame) {
@@ -996,10 +988,10 @@ static bool split_seq_list(
           }
         }
         else if (seq->enddisp <= split_frame) {
-          /* do nothing */
+          /* Pass. */
         }
         else if (seq->startdisp >= split_frame) {
-          /* move to tail */
+          /* Move to tail. */
           BLI_remlink(slist, seq);
           BLI_addtail(slist, seq);
 
@@ -1022,7 +1014,7 @@ static bool sequence_offset_after_frame(Scene *scene, const int delta, const int
   bool done = false;
   TimeMarker *marker;
 
-  /* all strips >= cfra are shifted */
+  /* All strips >= cfra are shifted. */
 
   if (ed == NULL) {
     return 0;
@@ -1085,12 +1077,12 @@ static void UNUSED_FUNCTION(seq_remap_paths)(Scene *scene)
   }
 
   BLI_strncpy(from, last_seq->strip->dir, sizeof(from));
-  // XXX  if (0 == sbutton(from, 0, sizeof(from) - 1, "From: "))
-  //      return;
+  /* XXX  if (0 == sbutton(from, 0, sizeof(from) - 1, "From: "))
+   *      return; */
 
   BLI_strncpy(to, from, sizeof(to));
-  // XXX  if (0 == sbutton(to, 0, sizeof(to) - 1, "To: "))
-  //      return;
+  /* XXX  if (0 == sbutton(to, 0, sizeof(to) - 1, "To: "))
+   *      return; */
 
   if (STREQ(to, from)) {
     return;
@@ -1101,11 +1093,11 @@ static void UNUSED_FUNCTION(seq_remap_paths)(Scene *scene)
       if (STREQLEN(seq->strip->dir, from, strlen(from))) {
         printf("found %s\n", seq->strip->dir);
 
-        /* strip off the beginning */
+        /* Strip off the beginning. */
         stripped[0] = 0;
         BLI_strncpy(stripped, seq->strip->dir + strlen(from), FILE_MAX);
 
-        /* new path */
+        /* New path. */
         BLI_snprintf(seq->strip->dir, sizeof(seq->strip->dir), "%s%s", to, stripped);
         printf("new %s\n", seq->strip->dir);
       }
@@ -1122,12 +1114,12 @@ static int sequencer_gap_remove_exec(bContext *C, wmOperator *op)
   bool first = false, done;
   bool do_all = RNA_boolean_get(op->ptr, "all");
 
-  /* get first and last frame */
+  /* Get first and last frame. */
   boundbox_seq(scene, &rectf);
   sfra = (int)rectf.xmin;
   efra = (int)rectf.xmax;
 
-  /* first check if the current frame has a gap already */
+  /* Check if the current frame has a gap already. */
   for (cfra = CFRA; cfra >= sfra; cfra--) {
     if (BKE_sequencer_evaluate_frame(scene, cfra)) {
       first = true;
@@ -1136,7 +1128,7 @@ static int sequencer_gap_remove_exec(bContext *C, wmOperator *op)
   }
 
   for (; cfra < efra; cfra++) {
-    /* first == 0 means there's still no strip to remove a gap for */
+    /* There's still no strip to remove a gap for. */
     if (first == false) {
       if (BKE_sequencer_evaluate_frame(scene, cfra)) {
         first = true;
@@ -1164,19 +1156,19 @@ static int sequencer_gap_remove_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_gap_remove(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Remove Gaps";
   ot->idname = "SEQUENCER_OT_gap_remove";
   ot->description =
       "Remove gap at current frame to first strip at the right, independent of selection or "
       "locked state of strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   //  ot->invoke = sequencer_snap_invoke;
   ot->exec = sequencer_gap_remove_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_boolean(ot->srna, "all", 0, "All Gaps", "Do all gaps to right of current frame");
@@ -1196,19 +1188,19 @@ static int sequencer_gap_insert_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_gap_insert(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Insert Gaps";
   ot->idname = "SEQUENCER_OT_gap_insert";
   ot->description =
       "Insert gap at current frame to first strips at the right, independent of selection or "
       "locked state of strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   //  ot->invoke = sequencer_snap_invoke;
   ot->exec = sequencer_gap_insert_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_int(ot->srna,
@@ -1238,7 +1230,7 @@ static int seq_get_snaplimit(View2D *v2d)
 }
 #endif
 
-/* Operator functions */
+/* Operator functions. */
 bool sequencer_edit_poll(bContext *C)
 {
   return (BKE_sequencer_editing_get(CTX_data_scene(C), false) != NULL);
@@ -1282,7 +1274,7 @@ bool sequencer_view_strips_poll(bContext *C)
   return 0;
 }
 
-/* snap operator*/
+/* Snap operator. */
 static int sequencer_snap_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -1293,14 +1285,11 @@ static int sequencer_snap_exec(bContext *C, wmOperator *op)
 
   snap_frame = RNA_int_get(op->ptr, "frame");
 
-  /* also check metas */
+  /* Check metas. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if (seq->flag & SELECT && !(seq->depth == 0 && seq->flag & SEQ_LOCK) &&
         BKE_sequence_tx_test(seq)) {
       if ((seq->flag & (SEQ_LEFTSEL + SEQ_RIGHTSEL)) == 0) {
-        /* simple but no anim update */
-        /* seq->start = snap_frame-seq->startofs+seq->startstill; */
-
         BKE_sequence_translate(
             scene, seq, (snap_frame - seq->startofs + seq->startstill) - seq->start);
       }
@@ -1318,8 +1307,8 @@ static int sequencer_snap_exec(bContext *C, wmOperator *op)
     }
   }
 
-  /* test for effects and overlap
-   * don't use SEQP_BEGIN since that would be recursive */
+  /* Test for effects and overlap.
+   * Don't use SEQP_BEGIN since that would be recursive. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if (seq->flag & SELECT && !(seq->depth == 0 && seq->flag & SEQ_LOCK)) {
       seq->flag &= ~SEQ_OVERLAP;
@@ -1340,7 +1329,6 @@ static int sequencer_snap_exec(bContext *C, wmOperator *op)
     }
   }
 
-  /* as last: */
   BKE_sequencer_sort(scene);
 
   DEG_id_tag_update(&scene->id, ID_RECALC_SEQUENCER_STRIPS);
@@ -1363,17 +1351,17 @@ static int sequencer_snap_invoke(bContext *C, wmOperator *op, const wmEvent *UNU
 
 void SEQUENCER_OT_snap(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Snap Strips to Playhead";
   ot->idname = "SEQUENCER_OT_snap";
   ot->description = "Frame where selected strips will be snapped";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_snap_invoke;
   ot->exec = sequencer_snap_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_int(ot->srna,
@@ -1395,7 +1383,7 @@ typedef struct SlipData {
   bool *trim;
   int num_seq;
   bool slow;
-  int slow_offset; /* offset at the point where offset was turned on */
+  int slow_offset; /* Offset at the point where offset was turned on. */
   NumInput num_input;
 } SlipData;
 
@@ -1442,7 +1430,7 @@ static int slip_add_sequences_recursive(
       num_items++;
 
       if (seq->type == SEQ_TYPE_META) {
-        /* trim the sub-sequences */
+        /* Trim the sub-sequences. */
         num_items += slip_add_sequences_recursive(
             &seq->seqbase, seq_array, trim, num_items + offset, false);
       }
@@ -1465,7 +1453,7 @@ static int slip_count_sequences_recursive(ListBase *seqbasep, bool first_level)
       trimmed_sequences++;
 
       if (seq->type == SEQ_TYPE_META) {
-        /* trim the sub-sequences */
+        /* Trim the sub-sequences. */
         trimmed_sequences += slip_count_sequences_recursive(&seq->seqbase, false);
       }
     }
@@ -1483,7 +1471,7 @@ static int sequencer_slip_invoke(bContext *C, wmOperator *op, const wmEvent *eve
   int num_seq, i;
   View2D *v2d = UI_view2d_fromcontext(C);
 
-  /* first recursively count the trimmed elements */
+  /* Recursively count the trimmed elements. */
   num_seq = slip_count_sequences_recursive(ed->seqbasep, true);
 
   if (num_seq == 0) {
@@ -1517,7 +1505,7 @@ static int sequencer_slip_invoke(bContext *C, wmOperator *op, const wmEvent *eve
 
   WM_event_add_modal_handler(C, op);
 
-  /* notify so we draw extensions immediately */
+  /* Notify so we draw extensions immediately. */
   WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER, scene);
 
   return OPERATOR_RUNNING_MODAL;
@@ -1529,20 +1517,19 @@ static bool sequencer_slip_recursively(Scene *scene, SlipData *data, int offset)
   Editing *ed = BKE_sequencer_editing_get(scene, false);
   bool changed = false;
 
-  /* We iterate in reverse so meta-strips are iterated after their children. */
+  /* Iterate in reverse so meta-strips are iterated after their children. */
   for (int i = data->num_seq - 1; i >= 0; i--) {
     Sequence *seq = data->seq_array[i];
     int endframe;
-    /* We have the offset, apply the values to the sequence strips. */
 
-    /* first, do the offset */
+    /* Offset seq start. */
     seq->start = data->ts[i].start + offset;
 
     if (data->trim[i]) {
       /* Find the end-frame. */
       endframe = seq->start + seq->len;
 
-      /* Now compute the sequence offsets. */
+      /* Compute the sequence offsets. */
       if (endframe > seq->enddisp) {
         seq->endstill = 0;
         seq->endofs = endframe - seq->enddisp;
@@ -1566,7 +1553,7 @@ static bool sequencer_slip_recursively(Scene *scene, SlipData *data, int offset)
       }
     }
     else {
-      /* If no real trim, don't change the data, rather transform the strips themselves. */
+      /* No transform data (likely effect strip). Only move start and end. */
       seq->startdisp = data->ts[i].startdisp + offset;
       seq->enddisp = data->ts[i].enddisp + offset;
       changed = true;
@@ -1575,7 +1562,7 @@ static bool sequencer_slip_recursively(Scene *scene, SlipData *data, int offset)
     /* Effects are only added if we they are in a meta-strip.
      * In this case, dependent strips will just be transformed and
      * we can skip calculating for effects.
-     * This way we can avoid an extra loop just for effects*/
+     * This way we can avoid an extra loop just for effects. */
     if (!(seq->type & SEQ_TYPE_EFFECT)) {
       BKE_sequence_calc(scene, seq);
     }
@@ -1595,7 +1582,7 @@ static int sequencer_slip_exec(bContext *C, wmOperator *op)
   int offset = RNA_int_get(op->ptr, "offset");
   bool success = false;
 
-  /* first recursively count the trimmed elements */
+  /* Recursively count the trimmed elements. */
   num_seq = slip_count_sequences_recursive(ed->seqbasep, true);
 
   if (num_seq == 0) {
@@ -1658,7 +1645,7 @@ static int sequencer_slip_modal(bContext *C, wmOperator *op, const wmEvent *even
   const bool has_numInput = hasNumInput(&data->num_input);
   bool handled = true;
 
-  /* Modal numinput active, try to handle numeric inputs first... */
+  /* Modal numinput active, try to handle numeric inputs. */
   if (event->val == KM_PRESS && has_numInput && handleNumInput(C, &data->num_input, event)) {
     float offset;
     applyNumInput(&data->num_input, &offset);
@@ -1691,7 +1678,7 @@ static int sequencer_slip_modal(bContext *C, wmOperator *op, const wmEvent *even
           mouse_x = event->mval[0];
         }
 
-        /* choose the side based on which side of the playhead the mouse is on */
+        /* Choose the side based on which side of the playhead the mouse is. */
         UI_view2d_region_to_view(v2d, mouse_x, 0, &mouseloc[0], &mouseloc[1]);
         offset = mouseloc[0] - data->init_mouseloc[0];
 
@@ -1772,7 +1759,7 @@ static int sequencer_slip_modal(bContext *C, wmOperator *op, const wmEvent *even
       break;
   }
 
-  /* Modal numinput inactive, try to handle numeric inputs last... */
+  /* Modal numinput inactive, try to handle numeric inputs. */
   if (!handled && event->val == KM_PRESS && handleNumInput(C, &data->num_input, event)) {
     float offset;
     applyNumInput(&data->num_input, &offset);
@@ -1791,18 +1778,18 @@ static int sequencer_slip_modal(bContext *C, wmOperator *op, const wmEvent *even
 
 void SEQUENCER_OT_slip(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Trim Strips";
   ot->idname = "SEQUENCER_OT_slip";
   ot->description = "Trim the contents of the active strip";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_slip_invoke;
   ot->modal = sequencer_slip_modal;
   ot->exec = sequencer_slip_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_int(ot->srna,
@@ -1816,7 +1803,7 @@ void SEQUENCER_OT_slip(struct wmOperatorType *ot)
               INT32_MAX);
 }
 
-/* mute operator */
+/* Mute operator. */
 static int sequencer_mute_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -1828,7 +1815,7 @@ static int sequencer_mute_exec(bContext *C, wmOperator *op)
 
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if ((seq->flag & SEQ_LOCK) == 0) {
-      if (selected) { /* mute unselected */
+      if (selected) {
         if (seq->flag & SELECT) {
           seq->flag |= SEQ_MUTE;
           BKE_sequence_invalidate_dependent(scene, seq);
@@ -1851,23 +1838,23 @@ static int sequencer_mute_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_mute(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Mute Strips";
   ot->idname = "SEQUENCER_OT_mute";
   ot->description = "Mute (un)selected strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_mute_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_boolean(
       ot->srna, "unselected", 0, "Unselected", "Mute unselected rather than selected strips");
 }
 
-/* unmute operator */
+/* Unmute operator. */
 static int sequencer_unmute_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -1879,7 +1866,7 @@ static int sequencer_unmute_exec(bContext *C, wmOperator *op)
 
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if ((seq->flag & SEQ_LOCK) == 0) {
-      if (selected) { /* unmute unselected */
+      if (selected) {
         if (seq->flag & SELECT) {
           seq->flag &= ~SEQ_MUTE;
           BKE_sequence_invalidate_dependent(scene, seq);
@@ -1902,23 +1889,23 @@ static int sequencer_unmute_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_unmute(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Unmute Strips";
   ot->idname = "SEQUENCER_OT_unmute";
   ot->description = "Unmute (un)selected strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_unmute_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_boolean(
       ot->srna, "unselected", 0, "Unselected", "Unmute unselected rather than selected strips");
 }
 
-/* lock operator */
+/* Lock operator. */
 static int sequencer_lock_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Scene *scene = CTX_data_scene(C);
@@ -1938,20 +1925,20 @@ static int sequencer_lock_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_lock(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Lock Strips";
   ot->idname = "SEQUENCER_OT_lock";
   ot->description = "Lock strips so they can't be transformed";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_lock_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* unlock operator */
+/* Unlock operator. */
 static int sequencer_unlock_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Scene *scene = CTX_data_scene(C);
@@ -1971,20 +1958,20 @@ static int sequencer_unlock_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_unlock(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Unlock Strips";
   ot->idname = "SEQUENCER_OT_unlock";
   ot->description = "Unlock strips so they can be transformed";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_unlock_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* reload operator */
+/* Reload operator. */
 static int sequencer_reload_exec(bContext *C, wmOperator *op)
 {
   Main *bmain = CTX_data_main(C);
@@ -2015,17 +2002,17 @@ void SEQUENCER_OT_reload(struct wmOperatorType *ot)
 {
   PropertyRNA *prop;
 
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Reload Strips";
   ot->idname = "SEQUENCER_OT_reload";
   ot->description = "Reload strips in the sequencer";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_reload_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
-  ot->flag = OPTYPE_REGISTER; /* no undo, the data changed is stored outside 'main' */
+  /* Flags. */
+  ot->flag = OPTYPE_REGISTER; /* No undo, the data changed is stored outside 'main'. */
 
   prop = RNA_def_boolean(ot->srna,
                          "adjust_length",
@@ -2035,7 +2022,7 @@ void SEQUENCER_OT_reload(struct wmOperatorType *ot)
   RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 }
 
-/* reload operator */
+/* Reload operator. */
 static bool sequencer_refresh_all_poll(bContext *C)
 {
   if (G.is_rendering) {
@@ -2058,12 +2045,12 @@ static int sequencer_refresh_all_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_refresh_all(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Refresh Sequencer";
   ot->idname = "SEQUENCER_OT_refresh_all";
   ot->description = "Refresh the sequencer editor";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_refresh_all_exec;
   ot->poll = sequencer_refresh_all_poll;
 }
@@ -2079,7 +2066,7 @@ static int sequencer_reassign_inputs_exec(bContext *C, wmOperator *op)
     BKE_report(op->reports, RPT_ERROR, error_msg);
     return OPERATOR_CANCELLED;
   }
-  /* see reassigning would create a cycle */
+  /* Check if reassigning would create recursivity. */
   if (seq_is_predecessor(seq1, last_seq) || seq_is_predecessor(seq2, last_seq) ||
       seq_is_predecessor(seq3, last_seq)) {
     BKE_report(op->reports, RPT_ERROR, "Cannot reassign inputs: no cycles allowed");
@@ -2114,16 +2101,16 @@ static bool sequencer_effect_poll(bContext *C)
 
 void SEQUENCER_OT_reassign_inputs(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Reassign Inputs";
   ot->idname = "SEQUENCER_OT_reassign_inputs";
   ot->description = "Reassign the inputs for the effect strip";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_reassign_inputs_exec;
   ot->poll = sequencer_effect_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
@@ -2149,20 +2136,20 @@ static int sequencer_swap_inputs_exec(bContext *C, wmOperator *op)
 }
 void SEQUENCER_OT_swap_inputs(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Swap Inputs";
   ot->idname = "SEQUENCER_OT_swap_inputs";
   ot->description = "Swap the first two inputs for the effect strip";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_swap_inputs_exec;
   ot->poll = sequencer_effect_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* split operator */
+/* Split operator. */
 static const EnumPropertyItem prop_split_types[] = {
     {SEQ_SPLIT_SOFT, "SOFT", 0, "Soft", ""},
     {SEQ_SPLIT_HARD, "HARD", 0, "Hard", ""},
@@ -2203,7 +2190,7 @@ static int sequencer_split_exec(bContext *C, wmOperator *op)
                              use_cursor_position,
                              split_seq_soft);
   }
-  if (changed) { /* got new strips ? */
+  if (changed) { /* Got new strips? */
     Sequence *seq;
     if (ignore_selection) {
       if (use_cursor_position) {
@@ -2246,7 +2233,7 @@ static int sequencer_split_exec(bContext *C, wmOperator *op)
       }
     }
     SEQ_END;
-    /* as last: */
+
     BKE_sequencer_sort(scene);
   }
   if (changed) {
@@ -2285,24 +2272,24 @@ static int sequencer_split_invoke(bContext *C, wmOperator *op, const wmEvent *ev
   }
   RNA_int_set(op->ptr, "channel", mouseloc[1]);
   RNA_enum_set(op->ptr, "side", split_side);
-  /*RNA_enum_set(op->ptr, "type", split_hard); */ /*This type is set from the key
-                                                     shortsplit */
+  /*RNA_enum_set(op->ptr, "type", split_hard); */
+
   return sequencer_split_exec(C, op);
 }
 
 void SEQUENCER_OT_split(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Split Strips";
   ot->idname = "SEQUENCER_OT_split";
   ot->description = "Split the selected strips in two";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_split_invoke;
   ot->exec = sequencer_split_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   PropertyRNA *prop;
@@ -2358,7 +2345,7 @@ void SEQUENCER_OT_split(struct wmOperatorType *ot)
 
 #undef SEQ_SIDE_MOUSE
 
-/* duplicate operator */
+/* Duplicate operator. */
 static int apply_unique_name_fn(Sequence *seq, void *arg_pt)
 {
   Scene *scene = (Scene *)arg_pt;
@@ -2385,7 +2372,7 @@ static int sequencer_add_duplicate_exec(bContext *C, wmOperator *UNUSED(op))
 
   if (nseqbase.first) {
     Sequence *seq = nseqbase.first;
-    /* rely on the nseqbase list being added at the end */
+    /* Rely on the nseqbase list being added at the end. */
     BLI_movelisttolist(ed->seqbasep, &nseqbase);
 
     for (; seq; seq = seq->next) {
@@ -2401,20 +2388,20 @@ static int sequencer_add_duplicate_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_duplicate(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Duplicate Strips";
   ot->idname = "SEQUENCER_OT_duplicate";
   ot->description = "Duplicate the selected strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_add_duplicate_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* delete operator */
+/* Delete operator. */
 static int sequencer_delete_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Main *bmain = CTX_data_main(C);
@@ -2425,7 +2412,7 @@ static int sequencer_delete_exec(bContext *C, wmOperator *UNUSED(op))
   bool nothing_selected = true;
 
   seq = BKE_sequencer_active_get(scene);
-  if (seq && seq->flag & SELECT) { /* avoid a loop since this is likely to be selected */
+  if (seq && seq->flag & SELECT) { /* Avoid a loop since this is likely to be selected. */
     nothing_selected = false;
   }
   else {
@@ -2441,7 +2428,7 @@ static int sequencer_delete_exec(bContext *C, wmOperator *UNUSED(op))
     return OPERATOR_FINISHED;
   }
 
-  /* for effects and modifiers, try to find a replacement input */
+  /* For effects and modifiers, try to find a replacement input. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if (!(seq->flag & SELECT)) {
       if ((seq->type & SEQ_TYPE_EFFECT)) {
@@ -2453,17 +2440,17 @@ static int sequencer_delete_exec(bContext *C, wmOperator *UNUSED(op))
     }
   }
 
-  /* delete all selected strips */
+  /* Delete all selected strips. */
   recurs_del_seq_flag(scene, ed->seqbasep, SELECT, 0);
 
-  /* updates lengths etc */
+  /* Update lengths, etc. */
   seq = ed->seqbasep->first;
   while (seq) {
     BKE_sequence_calc(scene, seq);
     seq = seq->next;
   }
 
-  /* free parent metas */
+  /* Free parent metas. */
   ms = ed->metastack.last;
   while (ms) {
     BKE_sequence_calc(scene, ms->parseq);
@@ -2482,8 +2469,8 @@ static int sequencer_delete_invoke(bContext *C, wmOperator *op, const wmEvent *e
   ARegion *region = CTX_wm_region(C);
 
   if (region->regiontype == RGN_TYPE_WINDOW) {
-    /* bounding box of 30 pixels is used for markers shortcuts,
-     * prevent conflict with markers shortcuts here
+    /* Bounding box of 30 pixels is used for markers shortcuts,
+     * prevent conflict with markers shortcuts here.
      */
     if (event->mval[1] <= 30) {
       return OPERATOR_PASS_THROUGH;
@@ -2496,35 +2483,35 @@ static int sequencer_delete_invoke(bContext *C, wmOperator *op, const wmEvent *e
 void SEQUENCER_OT_delete(wmOperatorType *ot)
 {
 
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Erase Strips";
   ot->idname = "SEQUENCER_OT_delete";
   ot->description = "Erase selected strips from the sequencer";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_delete_invoke;
   ot->exec = sequencer_delete_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* offset clear operator */
+/* Offset clear operator. */
 static int sequencer_offset_clear_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Scene *scene = CTX_data_scene(C);
   Editing *ed = BKE_sequencer_editing_get(scene, false);
   Sequence *seq;
 
-  /* for effects, try to find a replacement input */
+  /* For effects, try to find a replacement input. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if ((seq->type & SEQ_TYPE_EFFECT) == 0 && (seq->flag & SELECT)) {
       seq->startofs = seq->endofs = seq->startstill = seq->endstill = 0;
     }
   }
 
-  /* updates lengths etc */
+  /* Update lengths, etc. */
   seq = ed->seqbasep->first;
   while (seq) {
     BKE_sequence_calc(scene, seq);
@@ -2547,20 +2534,20 @@ static int sequencer_offset_clear_exec(bContext *C, wmOperator *UNUSED(op))
 void SEQUENCER_OT_offset_clear(wmOperatorType *ot)
 {
 
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Clear Strip Offset";
   ot->idname = "SEQUENCER_OT_offset_clear";
   ot->description = "Clear strip offsets from the start and end frames";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_offset_clear_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* separate_images operator */
+/* Separate_images operator. */
 static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -2572,13 +2559,13 @@ static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
   int start_ofs, cfra, frame_end;
   int step = RNA_int_get(op->ptr, "length");
 
-  seq = ed->seqbasep->first; /* poll checks this is valid */
+  seq = ed->seqbasep->first; /* Poll checks this is valid. */
 
   while (seq) {
     if ((seq->flag & SELECT) && (seq->type == SEQ_TYPE_IMAGE) && (seq->len > 1)) {
       Sequence *seq_next;
 
-      /* remove seq so overlap tests don't conflict,
+      /* Remove seq so overlap tests don't conflict,
        * see seq_free_sequence below for the real freeing. */
       BLI_remlink(ed->seqbasep, seq);
       /* if (seq->ipo) id_us_min(&seq->ipo->id); */
@@ -2588,7 +2575,7 @@ static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
       frame_end = BKE_sequence_tx_get_final_right(seq, false);
 
       while (cfra < frame_end) {
-        /* new seq */
+        /* New seq. */
         se = BKE_sequencer_give_stripelem(seq, cfra);
 
         seq_new = BKE_sequence_dupli_recursive(
@@ -2599,11 +2586,11 @@ static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
         seq_new->len = 1;
         seq_new->endstill = step - 1;
 
-        /* new strip */
+        /* New strip. */
         strip_new = seq_new->strip;
         strip_new->us = 1;
 
-        /* new stripdata (only one element now!) */
+        /* New stripdata, only one element now. */
         /* Note this assume all elements (images) have the same dimension,
          * since we only copy the name here. */
         se_new = MEM_reallocN(strip_new->stripdata, sizeof(*se_new));
@@ -2634,7 +2621,6 @@ static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
     }
   }
 
-  /* as last: */
   BKE_sequencer_sort(scene);
 
   WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER, scene);
@@ -2644,25 +2630,25 @@ static int sequencer_separate_images_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_images_separate(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Separate Images";
   ot->idname = "SEQUENCER_OT_images_separate";
   ot->description = "On image sequence strips, it returns a strip for each image";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_separate_images_exec;
   ot->invoke = WM_operator_props_popup_confirm;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   RNA_def_int(ot->srna, "length", 1, 1, INT_MAX, "Length", "Length of each frame", 1, 1000);
 }
 
-/* META Operators */
+/* META Operators. */
 
-/* separate_meta_toggle operator */
+/* Separate_meta_toggle operator. */
 static int sequencer_meta_toggle_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Scene *scene = CTX_data_scene(C);
@@ -2671,7 +2657,7 @@ static int sequencer_meta_toggle_exec(bContext *C, wmOperator *UNUSED(op))
   MetaStack *ms;
 
   if (last_seq && last_seq->type == SEQ_TYPE_META && last_seq->flag & SELECT) {
-    /* Enter Metastrip */
+    /* Enter metastrip. */
     ms = MEM_mallocN(sizeof(MetaStack), "metastack");
     BLI_addtail(&ed->metastack, ms);
     ms->parseq = last_seq;
@@ -2683,7 +2669,7 @@ static int sequencer_meta_toggle_exec(bContext *C, wmOperator *UNUSED(op))
     BKE_sequencer_active_set(scene, NULL);
   }
   else {
-    /* Exit Metastrip (if possible) */
+    /* Exit metastrip if possible. */
 
     Sequence *seq;
 
@@ -2696,18 +2682,18 @@ static int sequencer_meta_toggle_exec(bContext *C, wmOperator *UNUSED(op))
 
     ed->seqbasep = ms->oldbasep;
 
-    /* for old files, update from meta */
+    /* For old files, update from meta. */
     if (ms->disp_range[0] == ms->disp_range[1]) {
       copy_v2_v2_int(ms->disp_range, &ms->parseq->startdisp);
     }
 
-    /* recalc all: the meta can have effects connected to it */
+    /* Recalc all: the meta can have effects connected to it. */
     for (seq = ed->seqbasep->first; seq; seq = seq->next) {
       BKE_sequence_calc(scene, seq);
     }
 
     /* 2.73+, keeping endpoints is important!
-     * moving them around means you can't usefully use metas in a complex edit. */
+     * Moving them around means you can't usefully use metas in a complex edit. */
 #if 1
     BKE_sequence_tx_set_final_left(ms->parseq, ms->disp_range[0]);
     BKE_sequence_tx_set_final_right(ms->parseq, ms->disp_range[1]);
@@ -2735,20 +2721,20 @@ static int sequencer_meta_toggle_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_meta_toggle(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Toggle Meta Strip";
   ot->idname = "SEQUENCER_OT_meta_toggle";
   ot->description = "Toggle a metastrip (to edit enclosed strips)";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_meta_toggle_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* separate_meta_make operator */
+/* Separate_meta_make operator. */
 static int sequencer_meta_make_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -2762,9 +2748,9 @@ static int sequencer_meta_make_exec(bContext *C, wmOperator *op)
     return OPERATOR_CANCELLED;
   }
 
-  /* remove all selected from main list, and put in meta */
+  /* Remove all selected from main list, and put in meta. */
 
-  seqm = BKE_sequence_alloc(ed->seqbasep, 1, 1, SEQ_TYPE_META); /* channel number set later */
+  seqm = BKE_sequence_alloc(ed->seqbasep, 1, 1, SEQ_TYPE_META); /* Channel number set later. */
   strcpy(seqm->name + 2, "MetaStrip");
   seqm->flag = SELECT;
 
@@ -2799,16 +2785,16 @@ static int sequencer_meta_make_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_meta_make(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Make Meta Strip";
   ot->idname = "SEQUENCER_OT_meta_make";
   ot->description = "Group selected strips into a metastrip";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_meta_make_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
@@ -2831,7 +2817,7 @@ static int seq_depends_on_meta(Sequence *seq, Sequence *seqm)
   }
 }
 
-/* separate_meta_make operator */
+/* Separate_meta_make operator. */
 static int sequencer_meta_separate_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Scene *scene = CTX_data_scene(C);
@@ -2854,7 +2840,7 @@ static int sequencer_meta_separate_exec(bContext *C, wmOperator *UNUSED(op))
   BLI_remlink(ed->seqbasep, last_seq);
   BKE_sequence_free(scene, last_seq);
 
-  /* empty meta strip, delete all effects depending on it */
+  /* Empty meta strip, delete all effects depending on it. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if ((seq->type & SEQ_TYPE_EFFECT) && seq_depends_on_meta(seq, last_seq)) {
       seq->flag |= SEQ_FLAG_DELETE;
@@ -2863,8 +2849,8 @@ static int sequencer_meta_separate_exec(bContext *C, wmOperator *UNUSED(op))
 
   recurs_del_seq_flag(scene, ed->seqbasep, SEQ_FLAG_DELETE, 0);
 
-  /* test for effects and overlap
-   * don't use SEQP_BEGIN since that would be recursive */
+  /* Test for effects and overlap
+   * don't use SEQP_BEGIN since that would be recursive. */
   for (seq = ed->seqbasep->first; seq; seq = seq->next) {
     if (seq->flag & SELECT) {
       seq->flag &= ~SEQ_OVERLAP;
@@ -2884,20 +2870,20 @@ static int sequencer_meta_separate_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_meta_separate(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "UnMeta Strip";
   ot->idname = "SEQUENCER_OT_meta_separate";
   ot->description = "Put the contents of a metastrip back in the sequencer";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_meta_separate_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 }
 
-/* view_all operator */
+/* View_all operator. */
 static int sequencer_view_all_exec(bContext *C, wmOperator *op)
 {
   ARegion *region = CTX_wm_region(C);
@@ -2912,16 +2898,16 @@ static int sequencer_view_all_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_view_all(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "View All";
   ot->idname = "SEQUENCER_OT_view_all";
   ot->description = "View all the strips in the sequencer";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_all_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 }
 
@@ -2935,20 +2921,20 @@ static int sequencer_view_frame_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_view_frame(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Go to Current Frame";
   ot->idname = "SEQUENCER_OT_view_frame";
   ot->description = "Move the view to the playhead";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_frame_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = 0;
 }
 
-/* view_all operator */
+/* View_all operator. */
 static int sequencer_view_all_preview_exec(bContext *C, wmOperator *UNUSED(op))
 {
   bScreen *screen = CTX_wm_screen(C);
@@ -2965,7 +2951,7 @@ static int sequencer_view_all_preview_exec(bContext *C, wmOperator *UNUSED(op))
   UI_view2d_sync(screen, area, v2d, V2D_LOCK_COPY);
 
 #if 0
-  /* Like zooming on an image view */
+  /* Like zooming on an image view. */
   float zoomX, zoomY;
   int width, height, imgwidth, imgheight;
 
@@ -2977,11 +2963,11 @@ static int sequencer_view_all_preview_exec(bContext *C, wmOperator *UNUSED(op))
   imgwidth = (scene->r.size * scene->r.xsch) / 100;
   imgheight = (scene->r.size * scene->r.ysch) / 100;
 
-  /* Apply aspect, doesn't need to be that accurate */
+  /* Apply aspect, doesn't need to be that accurate. */
   imgwidth = (int)(imgwidth * (scene->r.xasp / scene->r.yasp));
 
   if (((imgwidth >= width) || (imgheight >= height)) && ((width > 0) && (height > 0))) {
-    /* Find the zoom value that will fit the image in the image space */
+    /* Find the zoom value that will fit the image in the image space. */
     zoomX = ((float)width) / ((float)imgwidth);
     zoomY = ((float)height) / ((float)imgheight);
     sseq->zoom = (zoomX < zoomY) ? zoomX : zoomY;
@@ -2999,16 +2985,16 @@ static int sequencer_view_all_preview_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_view_all_preview(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "View All";
   ot->idname = "SEQUENCER_OT_view_all_preview";
   ot->description = "Zoom preview to fit in the area";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_all_preview_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 }
 
@@ -3034,16 +3020,16 @@ static int sequencer_view_zoom_ratio_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_view_zoom_ratio(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Sequencer View Zoom Ratio";
   ot->idname = "SEQUENCER_OT_view_zoom_ratio";
   ot->description = "Change zoom ratio of sequencer preview";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_zoom_ratio_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* properties */
+  /* Properties. */
   RNA_def_float(ot->srna,
                 "ratio",
                 1.0f,
@@ -3068,7 +3054,7 @@ static const EnumPropertyItem view_type_items[] = {
 };
 #endif
 
-/* view_all operator */
+/* View_all operator. */
 static int sequencer_view_toggle_exec(bContext *C, wmOperator *UNUSED(op))
 {
   SpaceSeq *sseq = (SpaceSeq *)CTX_wm_space_data(C);
@@ -3085,20 +3071,20 @@ static int sequencer_view_toggle_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_view_toggle(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "View Toggle";
   ot->idname = "SEQUENCER_OT_view_toggle";
   ot->description = "Toggle between sequencer views (sequence, preview, both)";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_toggle_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 }
 
-/* view_selected operator */
+/* View_selected operator. */
 static int sequencer_view_selected_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -3148,7 +3134,7 @@ static int sequencer_view_selected_exec(bContext *C, wmOperator *op)
     cur_new.ymin = ymin;
     cur_new.ymax = ymax;
 
-    /* only zoom out vertically */
+    /* Only zoom out vertically. */
     if (orig_height > BLI_rctf_size_y(&cur_new)) {
       ymid = BLI_rctf_cent_y(&cur_new);
 
@@ -3167,16 +3153,16 @@ static int sequencer_view_selected_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_view_selected(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Frame Selected";
   ot->idname = "SEQUENCER_OT_view_selected";
   ot->description = "Zoom the sequencer on the selected strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_view_selected_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 }
 
@@ -3199,7 +3185,7 @@ static bool strip_jump_internal(Scene *scene,
 
 static bool sequencer_strip_jump_poll(bContext *C)
 {
-  /* prevent changes during render */
+  /* Prevent changes during render. */
   if (G.is_rendering) {
     return 0;
   }
@@ -3207,14 +3193,14 @@ static bool sequencer_strip_jump_poll(bContext *C)
   return sequencer_edit_poll(C);
 }
 
-/* jump frame to edit point operator */
+/* Jump frame to edit point operator. */
 static int sequencer_strip_jump_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
   const bool next = RNA_boolean_get(op->ptr, "next");
   const bool center = RNA_boolean_get(op->ptr, "center");
 
-  /* currently do_skip_mute is always true */
+  /* Currently do_skip_mute is always true. */
   if (!strip_jump_internal(scene, next ? SEQ_SIDE_RIGHT : SEQ_SIDE_LEFT, true, center)) {
     return OPERATOR_CANCELLED;
   }
@@ -3226,19 +3212,19 @@ static int sequencer_strip_jump_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_strip_jump(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Jump to Strip";
   ot->idname = "SEQUENCER_OT_strip_jump";
   ot->description = "Move frame to previous edit point";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_strip_jump_exec;
   ot->poll = sequencer_strip_jump_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_UNDO;
 
-  /* properties */
+  /* Properties. */
   RNA_def_boolean(ot->srna, "next", true, "Next Strip", "");
   RNA_def_boolean(ot->srna, "center", true, "Use strip center", "");
 }
@@ -3296,7 +3282,7 @@ static int sequencer_swap_exec(bContext *C, wmOperator *op)
 
   if (seq) {
 
-    /* disallow effect strips */
+    /* Disallow effect strips. */
     if (BKE_sequence_effect_get_num_inputs(seq->type) >= 1 &&
         (seq->effectdata || seq->seq1 || seq->seq2 || seq->seq3)) {
       return OPERATOR_CANCELLED;
@@ -3315,7 +3301,7 @@ static int sequencer_swap_exec(bContext *C, wmOperator *op)
         break;
     }
 
-    // XXX - should be a generic function
+    /* XXX - Should be a generic function. */
     for (iseq = scene->ed->seqbasep->first; iseq; iseq = iseq->next) {
       if ((iseq->type & SEQ_TYPE_EFFECT) &&
           (seq_is_parent(iseq, active_seq) || seq_is_parent(iseq, seq))) {
@@ -3323,11 +3309,11 @@ static int sequencer_swap_exec(bContext *C, wmOperator *op)
       }
     }
 
-    /* do this in a new loop since both effects need to be calculated first */
+    /* Do this in a new loop since both effects need to be calculated first. */
     for (iseq = scene->ed->seqbasep->first; iseq; iseq = iseq->next) {
       if ((iseq->type & SEQ_TYPE_EFFECT) &&
           (seq_is_parent(iseq, active_seq) || seq_is_parent(iseq, seq))) {
-        /* this may now overlap */
+        /* This may now overlap. */
         if (BKE_sequence_test_overlap(ed->seqbasep, iseq)) {
           BKE_sequence_base_shuffle(ed->seqbasep, iseq, scene);
         }
@@ -3346,19 +3332,19 @@ static int sequencer_swap_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_swap(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Swap Strip";
   ot->idname = "SEQUENCER_OT_swap";
   ot->description = "Swap active strip with strip to the right or left";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_swap_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
-  /* properties */
+  /* Properties. */
   RNA_def_enum(
       ot->srna, "side", prop_side_lr_types, SEQ_SIDE_RIGHT, "Side", "Side of the strip to swap");
 }
@@ -3392,7 +3378,7 @@ static int sequencer_rendersize_exec(bContext *C, wmOperator *UNUSED(op))
   }
 
   if (se) {
-    // prevent setting the render size if sequence values aren't initialized
+    /* Prevent setting the render size if sequence values aren't initialized. */
     if ((se->orig_width > 0) && (se->orig_height > 0)) {
       scene->r.xsch = se->orig_width;
       scene->r.ysch = se->orig_height;
@@ -3406,19 +3392,17 @@ static int sequencer_rendersize_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_rendersize(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Set Render Size";
   ot->idname = "SEQUENCER_OT_rendersize";
   ot->description = "Set render size and aspect from active sequence";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_rendersize_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
-
-  /* properties */
 }
 
 static void seq_copy_del_sound(Scene *scene, Sequence *seq)
@@ -3453,9 +3437,8 @@ static int sequencer_copy_exec(bContext *C, wmOperator *op)
   BKE_sequence_base_dupli_recursive(
       scene, scene, &nseqbase, ed->seqbasep, SEQ_DUPE_UNIQUE_NAME, LIB_ID_CREATE_NO_USER_REFCOUNT);
 
-  /* To make sure the copied strips have unique names between each other add
-   * them temporarily to the end of the original seqbase. (bug 25932)
-   */
+  /* Make sure that copied strips have unique names.
+   * Add them temporarily to the end of the original seqbase (bug 25932). */
   if (nseqbase.first) {
     Sequence *seq, *first_seq = nseqbase.first;
     BLI_movelisttolist(ed->seqbasep, &nseqbase);
@@ -3476,7 +3459,7 @@ static int sequencer_copy_exec(bContext *C, wmOperator *op)
 
   seqbase_clipboard_frame = scene->r.cfra;
 
-  /* Need to remove anything that references the current scene */
+  /* Remove anything that references the current scene. */
   LISTBASE_FOREACH (Sequence *, seq, &seqbase_clipboard) {
     seq_copy_del_sound(scene, seq);
   }
@@ -3490,26 +3473,24 @@ static int sequencer_copy_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_copy(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Copy";
   ot->idname = "SEQUENCER_OT_copy";
   ot->description = "Copy selected strips to clipboard";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_copy_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
-
-  /* properties */
 }
 
 static int sequencer_paste_exec(bContext *C, wmOperator *UNUSED(op))
 {
   Main *bmain = CTX_data_main(C);
   Scene *scene = CTX_data_scene(C);
-  Editing *ed = BKE_sequencer_editing_get(scene, true); /* create if needed */
+  Editing *ed = BKE_sequencer_editing_get(scene, true); /* Create if needed. */
   ListBase nseqbase = {NULL, NULL};
   int ofs;
   Sequence *iseq, *iseq_first;
@@ -3525,7 +3506,7 @@ static int sequencer_paste_exec(bContext *C, wmOperator *UNUSED(op))
       scene, scene, &nseqbase, &seqbase_clipboard, SEQ_DUPE_UNIQUE_NAME, 0);
   BKE_sequencer_base_clipboard_pointers_store(bmain, &seqbase_clipboard);
 
-  /* transform pasted strips before adding */
+  /* Transform pasted strips before adding. */
   if (ofs) {
     for (iseq = nseqbase.first; iseq; iseq = iseq->next) {
       BKE_sequence_translate(scene, iseq, ofs);
@@ -3536,12 +3517,12 @@ static int sequencer_paste_exec(bContext *C, wmOperator *UNUSED(op))
 
   BLI_movelisttolist(ed->seqbasep, &nseqbase);
 
-  /* make sure the pasted strips have unique names between them */
+  /* Make sure, that pasted strips have unique names. */
   for (iseq = iseq_first; iseq; iseq = iseq->next) {
     BKE_sequencer_recursive_apply(iseq, apply_unique_name_fn, scene);
   }
 
-  /* ensure pasted strips don't overlap */
+  /* Ensure, that pasted strips don't overlap. */
   for (iseq = iseq_first; iseq; iseq = iseq->next) {
     if (BKE_sequence_test_overlap(ed->seqbasep, iseq)) {
       BKE_sequence_base_shuffle(ed->seqbasep, iseq, scene);
@@ -3556,19 +3537,17 @@ static int sequencer_paste_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_paste(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Paste";
   ot->idname = "SEQUENCER_OT_paste";
   ot->description = "Paste strips from clipboard";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_paste_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
-
-  /* properties */
 }
 
 static int sequencer_swap_data_exec(bContext *C, wmOperator *op)
@@ -3619,22 +3598,20 @@ static int sequencer_swap_data_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_swap_data(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Sequencer Swap Data";
   ot->idname = "SEQUENCER_OT_swap_data";
   ot->description = "Swap 2 sequencer strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_swap_data_exec;
   ot->poll = ED_operator_sequencer_active;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
-
-  /* properties */
 }
 
-/* box select operator */
+/* Box select operator. */
 static int view_ghost_border_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -3642,7 +3619,7 @@ static int view_ghost_border_exec(bContext *C, wmOperator *op)
 
   rctf rect;
 
-  /* convert coordinates of rect to 'tot' rect coordinates */
+  /* Convert coordinates of rect to 'tot' rect coordinates. */
   WM_operator_properties_border_to_rctf(op, &rect);
   UI_view2d_region_to_view_rctf(v2d, &rect, &rect);
 
@@ -3669,30 +3646,28 @@ static int view_ghost_border_exec(bContext *C, wmOperator *op)
   return OPERATOR_FINISHED;
 }
 
-/* ****** Box Select ****** */
 void SEQUENCER_OT_view_ghost_border(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Border Offset View";
   ot->idname = "SEQUENCER_OT_view_ghost_border";
   ot->description = "Set the boundaries of the border used for offset-view";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = WM_gesture_box_invoke;
   ot->exec = view_ghost_border_exec;
   ot->modal = WM_gesture_box_modal;
   ot->poll = sequencer_view_preview_poll;
   ot->cancel = WM_gesture_box_cancel;
 
-  /* flags */
+  /* Flags. */
   ot->flag = 0;
 
-  /* rna */
+  /* Properties. */
   WM_operator_properties_gesture_box(ot);
 }
 
-/* rebuild_proxy operator */
-
+/* Rebuild_proxy operator. */
 static int sequencer_rebuild_proxy_invoke(bContext *C,
                                           wmOperator *op,
                                           const wmEvent *UNUSED(event))
@@ -3743,16 +3718,16 @@ static int sequencer_rebuild_proxy_exec(bContext *C, wmOperator *UNUSED(op))
 
 void SEQUENCER_OT_rebuild_proxy(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Rebuild Proxy and Timecode Indices";
   ot->idname = "SEQUENCER_OT_rebuild_proxy";
   ot->description = "Rebuild all selected proxies and timecode indices using the job system";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_rebuild_proxy_invoke;
   ot->exec = sequencer_rebuild_proxy_exec;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 }
 
@@ -3838,16 +3813,16 @@ static int sequencer_enable_proxies_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_enable_proxies(wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Set Selected Strip Proxies";
   ot->idname = "SEQUENCER_OT_enable_proxies";
   ot->description = "Enable selected proxies on all selected Movie, Image and Meta strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->invoke = sequencer_enable_proxies_invoke;
   ot->exec = sequencer_enable_proxies_exec;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER;
 
   RNA_def_boolean(ot->srna, "proxy_25", false, "25%", "");
@@ -3857,8 +3832,7 @@ void SEQUENCER_OT_enable_proxies(wmOperatorType *ot)
   RNA_def_boolean(ot->srna, "overwrite", false, "Overwrite", "");
 }
 
-/* change ops */
-
+/* Change effect inputs operator. */
 static const EnumPropertyItem prop_change_effect_input_types[] = {
     {0, "A_B", 0, "A -> B", ""},
     {1, "B_C", 0, "B -> C", ""},
@@ -3899,9 +3873,8 @@ static int sequencer_change_effect_input_exec(bContext *C, wmOperator *op)
 
   BKE_sequencer_update_changed_seq_and_deps(scene, seq, 0, 1);
 
-  /* important else we don't get the imbuf cache flushed */
+  /* Invalidate cache. */
   BKE_sequencer_free_imbuf(scene, &ed->seqbase, false);
-
   WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER, scene);
 
   return OPERATOR_FINISHED;
@@ -3909,21 +3882,22 @@ static int sequencer_change_effect_input_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_change_effect_input(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Change Effect Input";
   ot->idname = "SEQUENCER_OT_change_effect_input";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_change_effect_input_exec;
   ot->poll = sequencer_effect_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   ot->prop = RNA_def_enum(
       ot->srna, "swap", prop_change_effect_input_types, 0, "Swap", "The effect inputs to swap");
 }
 
+/* Change effect type operator. */
 static int sequencer_change_effect_type_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -3931,14 +3905,14 @@ static int sequencer_change_effect_type_exec(bContext *C, wmOperator *op)
   Sequence *seq = BKE_sequencer_active_get(scene);
   const int new_type = RNA_enum_get(op->ptr, "type");
 
-  /* free previous effect and init new effect */
+  /* Free previous effect and init new effect. */
   struct SeqEffectHandle sh;
 
   if ((seq->type & SEQ_TYPE_EFFECT) == 0) {
     return OPERATOR_CANCELLED;
   }
 
-  /* can someone explain the logic behind only allowing to increase this,
+  /* Can someone explain the logic behind only allowing to increase this,
    * copied from 2.4x - campbell */
   if (BKE_sequence_effect_get_num_inputs(seq->type) <
       BKE_sequence_effect_get_num_inputs(new_type)) {
@@ -3955,10 +3929,8 @@ static int sequencer_change_effect_type_exec(bContext *C, wmOperator *op)
     sh.init(seq);
   }
 
-  /* update */
   BKE_sequencer_update_changed_seq_and_deps(scene, seq, 0, 1);
-
-  /* important else we don't get the imbuf cache flushed */
+  /* Invalidate cache. */
   BKE_sequencer_free_imbuf(scene, &ed->seqbase, false);
 
   WM_event_add_notifier(C, NC_SCENE | ND_SEQUENCER, scene);
@@ -3968,15 +3940,15 @@ static int sequencer_change_effect_type_exec(bContext *C, wmOperator *op)
 
 void SEQUENCER_OT_change_effect_type(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Change Effect Type";
   ot->idname = "SEQUENCER_OT_change_effect_type";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_change_effect_type_exec;
   ot->poll = sequencer_effect_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   ot->prop = RNA_def_enum(ot->srna,
@@ -3987,6 +3959,7 @@ void SEQUENCER_OT_change_effect_type(struct wmOperatorType *ot)
                           "Sequencer effect type");
 }
 
+/* Change path operator. */
 static int sequencer_change_path_exec(bContext *C, wmOperator *op)
 {
   Main *bmain = CTX_data_main(C);
@@ -4002,7 +3975,7 @@ static int sequencer_change_path_exec(bContext *C, wmOperator *op)
     int len;
     StripElem *se;
 
-    /* need to find min/max frame for placeholders */
+    /* Need to find min/max frame for placeholders. */
     if (use_placeholders) {
       len = sequencer_image_seq_get_minmax_frame(op, seq->sfra, &minframe, &numdigits);
     }
@@ -4040,16 +4013,16 @@ static int sequencer_change_path_exec(bContext *C, wmOperator *op)
       RNA_END;
     }
 
-    /* reset these else we wont see all the images */
+    /* Reset these else we wont see all the images. */
     seq->anim_startofs = seq->anim_endofs = 0;
 
-    /* correct start/end frames so we don't move
-     * important not to set seq->len = len; allow the function to handle it */
+    /* Correct start/end frames so we don't move.
+     * Important not to set seq->len = len; allow the function to handle it. */
     BKE_sequence_reload_new_file(bmain, scene, seq, true);
 
     BKE_sequence_calc(scene, seq);
 
-    /* important else we don't get the imbuf cache flushed */
+    /* Invalidate cache. */
     BKE_sequencer_free_imbuf(scene, &ed->seqbase, false);
   }
   else if (ELEM(seq->type, SEQ_TYPE_SOUND_RAM, SEQ_TYPE_SOUND_HD)) {
@@ -4063,7 +4036,7 @@ static int sequencer_change_path_exec(bContext *C, wmOperator *op)
     BKE_sound_load(bmain, sound);
   }
   else {
-    /* lame, set rna filepath */
+    /* Lame, set rna filepath. */
     PointerRNA seq_ptr;
     PropertyRNA *prop;
     char filepath[FILE_MAX];
@@ -4092,7 +4065,7 @@ static int sequencer_change_path_invoke(bContext *C, wmOperator *op, const wmEve
   RNA_string_set(op->ptr, "directory", seq->strip->dir);
   RNA_string_set(op->ptr, "filepath", filepath);
 
-  /* set default display depending on seq type */
+  /* Set default display depending on seq type. */
   if (seq->type == SEQ_TYPE_IMAGE) {
     RNA_boolean_set(op->ptr, "filter_movie", false);
   }
@@ -4107,16 +4080,16 @@ static int sequencer_change_path_invoke(bContext *C, wmOperator *op, const wmEve
 
 void SEQUENCER_OT_change_path(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Change Data/Files";
   ot->idname = "SEQUENCER_OT_change_path";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_change_path_exec;
   ot->invoke = sequencer_change_path_invoke;
   ot->poll = sequencer_strip_has_path_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   WM_operator_properties_filesel(ot,
@@ -4134,6 +4107,7 @@ void SEQUENCER_OT_change_path(struct wmOperatorType *ot)
                   "Use placeholders for missing frames of the strip");
 }
 
+/* Export subtitles operator. */
 static int sequencer_export_subtitles_invoke(bContext *C,
                                              wmOperator *op,
                                              const wmEvent *UNUSED(event))
@@ -4176,7 +4150,7 @@ static int sequencer_export_subtitles_exec(bContext *C, wmOperator *op)
   RNA_string_get(op->ptr, "filepath", filepath);
   BLI_path_extension_ensure(filepath, sizeof(filepath), ".srt");
 
-  /* Avoid File write exceptions */
+  /* Avoid File write exceptions. */
   if (!BLI_exists(filepath)) {
     BLI_make_existing_file(filepath);
     if (!BLI_file_touch(filepath)) {
@@ -4203,7 +4177,7 @@ static int sequencer_export_subtitles_exec(bContext *C, wmOperator *op)
 
   BLI_listbase_sort(&text_seq, BKE_sequencer_cmp_time_startdisp);
 
-  /* time to open and write! */
+  /* Open and write file. */
   file = BLI_fopen(filepath, "w");
 
   for (seq = text_seq.first; seq; seq = seq_next) {
@@ -4246,17 +4220,17 @@ static bool sequencer_strip_is_text_poll(bContext *C)
 
 void SEQUENCER_OT_export_subtitles(struct wmOperatorType *ot)
 {
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Export Subtitles";
   ot->idname = "SEQUENCER_OT_export_subtitles";
   ot->description = "Export .srt file containing text strips";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_export_subtitles_exec;
   ot->invoke = sequencer_export_subtitles_invoke;
   ot->poll = sequencer_strip_is_text_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   WM_operator_properties_filesel(ot,
@@ -4268,6 +4242,7 @@ void SEQUENCER_OT_export_subtitles(struct wmOperatorType *ot)
                                  FILE_SORT_ALPHA);
 }
 
+/* Set range to strips operator. */
 static int sequencer_set_range_to_strips_exec(bContext *C, wmOperator *op)
 {
   Scene *scene = CTX_data_scene(C);
@@ -4316,16 +4291,16 @@ void SEQUENCER_OT_set_range_to_strips(struct wmOperatorType *ot)
 {
   PropertyRNA *prop;
 
-  /* identifiers */
+  /* Identifiers. */
   ot->name = "Set Range to Strips";
   ot->idname = "SEQUENCER_OT_set_range_to_strips";
   ot->description = "Set the frame range to the selected strips start and end";
 
-  /* api callbacks */
+  /* Api callbacks. */
   ot->exec = sequencer_set_range_to_strips_exec;
   ot->poll = sequencer_edit_poll;
 
-  /* flags */
+  /* Flags. */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
 
   prop = RNA_def_boolean(ot->srna, "preview", false, "Preview", "Set the preview range instead");