AVFilterBufferRef *ff_get_video_buffer(AVFilterLink *link, int perms,
int w, int h);
-void ff_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
-void ff_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
-void ff_null_end_frame(AVFilterLink *link);
+int ff_inplace_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
+int ff_null_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
+int ff_null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
+int ff_null_end_frame(AVFilterLink *link);
/**
* Notify the next filter of the start of a frame.
* frame need only be valid once draw_slice() is called for that
* portion. The receiving filter will free this reference when
* it no longer needs it.
+ *
+ * @return >= 0 on success, a negative AVERROR on error. This function will
+ * unreference picref in case of error.
*/
-void ff_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
+int ff_start_frame(AVFilterLink *link, AVFilterBufferRef *picref);
/**
* Notify the next filter that the current frame has finished.
*
* @param link the output link the frame was sent over
+ *
+ * @return >= 0 on success, a negative AVERROR on error
*/
-void ff_end_frame(AVFilterLink *link);
+int ff_end_frame(AVFilterLink *link);
/**
* Send a slice to the next filter.
* from the top slice to the bottom slice if the value is 1,
* from the bottom slice to the top slice if the value is -1,
* for other values the behavior of the function is undefined.
+ *
+ * @return >= 0 on success, a negative AVERROR on error.
*/
-void ff_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
+int ff_draw_slice(AVFilterLink *link, int y, int h, int slice_dir);
#endif /* AVFILTER_VIDEO_H */