lavfi: loop on request_frame if necessary.

Some filters need several input frames before producing output.
For these filter, it becomes simpler to return 0 in
request_frame() and let the framework call it again until
output has been produced.

1 files changed, 11 insertions, 0 deletions

diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 455161fa34..7583dccfbe 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -682,6 +682,17 @@ struct AVFilterLink {
      * Number of channels.
      */
     int channels;
+
+    /**
+     * True if a frame is being requested on the link.
+     * Used internally by the framework.
+     */
+    unsigned frame_requested;
+
+    /**
+     * Link processing flags.
+     */
+    unsigned flags;
 };
 
 /**