lavfi: support automatically inserting the fifo filter when needed.

This breaks libavfilter ABI.

1 files changed, 8 insertions, 0 deletions

diff --git a/libavfilter/internal.h b/libavfilter/internal.h
index 01b8f664f8..954610e3ca 100644
--- a/libavfilter/internal.h
+++ b/libavfilter/internal.h
@@ -149,6 +149,14 @@ struct AVFilterPad {
      * and another value on error.
      */
     int (*config_props)(AVFilterLink *link);
+
+    /**
+     * The filter expects a fifo to be inserted on its input link,
+     * typically because it has a delay.
+     *
+     * input pads only.
+     */
+    int needs_fifo;
 };
 #endif