lavfi: make request_frame() non-recursive.

Instead of calling the input filter request_frame() method,
ff_request_frame() now marks the link and returns immediately.
buffersink is changed to activate the marked filters until
a frame is obtained.

1 files changed, 14 insertions, 0 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index c52175b4c9..599369dcb0 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -520,6 +520,20 @@ struct AVFilterLink {
      * A pointer to a FFVideoFramePool struct.
      */
     void *video_frame_pool;
+
+    /**
+     * True if a frame is currently wanted on the input of this filter.
+     * Set when ff_request_frame() is called by the output,
+     * cleared when the request is handled or forwarded.
+     */
+    int frame_wanted_in;
+
+    /**
+     * True if a frame is currently wanted on the output of this filter.
+     * Set when ff_request_frame() is called by the output,
+     * cleared when a frame is filtered.
+     */
+    int frame_wanted_out;
 };
 
 /**