+ VFrame* get_frame_ptr(int64_t position, int layer, double frame_rate,
+ int color_model, int w, int h, int source_id);
+// lock and call get_vframe
+ VFrame *get_vframe(int64_t position, int w, int h,
+ int color_model, int layer, double frame_rate,
+ int source_id);
+// caller holds lock
+ VFrame *get_frame(int64_t position, int w, int h,
+ int color_model, int layer, double frame_rate,
+ int source_id);
+// Returns 1 if frame exists in cache and copies it to the frame argument.
+ int get_frame(VFrame *frame, int64_t position,
+ int layer, double frame_rate, int source_id);