VSE: prefetching

When enabled prefetching(preview panel>view settings), a pernament running job
is created, that will render frames in the background until the cache is full.
If the cache is not filled fast enough, prefetch job suspends itself
at the last moment and will wait until it has chance to "catch up".
Effectively this will decouple rendering to separate thread, so rendering
itself is a bit faster.
Cache recycling behavior will be changed to "free furthest frame to the left
of playhead if possible, otherwise rightmost frame".

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D5386

1 files changed, 26 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_sequencer.h b/source/blender/blenkernel/BKE_sequencer.h
index e1bc16702d5..16f766ae8bb 100644
--- a/source/blender/blenkernel/BKE_sequencer.h
+++ b/source/blender/blenkernel/BKE_sequencer.h
@@ -82,6 +82,11 @@ void BKE_sequence_iterator_end(SeqIterator *iter);
   } \
   ((void)0)
 
+typedef enum eSeqTaskId {
+  SEQ_TASK_MAIN_RENDER,
+  SEQ_TASK_PREFETCH_RENDER,
+} eSeqTaskId;
+
 typedef struct SeqRenderData {
   struct Main *bmain;
   struct Depsgraph *depsgraph;
@@ -94,7 +99,10 @@ typedef struct SeqRenderData {
   float motion_blur_shutter;
   bool skip_cache;
   bool is_proxy_render;
+  bool is_prefetch_render;
   int view_id;
+  /* ID of task for asigning temp cache entries to particular task(thread, etc.) */
+  eSeqTaskId task_id;
 
   /* special case for OpenGL render */
   struct GPUOffScreen *gpu_offscreen;
@@ -290,7 +298,7 @@ void BKE_sequencer_proxy_rebuild_context(struct Main *bmain,
 void BKE_sequencer_proxy_rebuild(struct SeqIndexBuildContext *context,
                                  short *stop,
                                  short *do_update,
-                                 float *progress);
+                                 float *num_frames_prefetched);
 void BKE_sequencer_proxy_rebuild_finish(struct SeqIndexBuildContext *context, bool stop);
 
 void BKE_sequencer_proxy_set(struct Sequence *seq, bool value);
@@ -318,6 +326,7 @@ bool BKE_sequencer_cache_put_if_possible(const SeqRenderData *context,
                                          int type,
                                          struct ImBuf *nval,
                                          float cost);
+bool BKE_sequencer_cache_recycle_item(struct Scene *scene);
 void BKE_sequencer_cache_free_temp_cache(struct Scene *scene, short id, int cfra);
 void BKE_sequencer_cache_destruct(struct Scene *scene);
 void BKE_sequencer_cache_cleanup_all(struct Main *bmain);
@@ -330,6 +339,22 @@ void BKE_sequencer_cache_iterate(
     struct Scene *scene,
     void *userdata,
     bool callback(void *userdata, struct Sequence *seq, int cfra, int cache_type, float cost));
+bool BKE_sequencer_cache_is_full(struct Scene *scene);
+
+/* **********************************************************************
+ * seqprefetch.c
+ *
+ * Sequencer frame prefetching
+ * ********************************************************************** */
+
+void BKE_sequencer_prefetch_start(const SeqRenderData *context, float cfra, float cost);
+void BKE_sequencer_prefetch_stop(struct Scene *scene);
+void BKE_sequencer_prefetch_free(struct Scene *scene);
+bool BKE_sequencer_prefetch_need_redraw(struct Main *bmain, struct Scene *scene);
+void BKE_sequencer_prefetch_get_time_range(struct Scene *scene, int *start, int *end);
+SeqRenderData *BKE_sequencer_prefetch_get_original_context(const SeqRenderData *context);
+struct Sequence *BKE_sequencer_prefetch_get_original_sequence(struct Sequence *seq,
+                                                              struct Scene *scene);
 
 /* **********************************************************************
  * seqeffects.c