decode: add a method for attaching lavc-internal data to frames

Use the AVFrame.opaque_ref field. The original user's opaque_ref is
wrapped in the lavc struct and then unwrapped before the frame is
returned to the caller.

This new struct will be useful in the following commits.

1 files changed, 13 insertions, 0 deletions

diff --git a/libavcodec/decode.h b/libavcodec/decode.h
index 2f29cf6107..61b53b2445 100644
--- a/libavcodec/decode.h
+++ b/libavcodec/decode.h
@@ -21,9 +21,22 @@
 #ifndef AVCODEC_DECODE_H
 #define AVCODEC_DECODE_H
 
+#include "libavutil/buffer.h"
+
 #include "avcodec.h"
 
 /**
+ * This struct stores per-frame lavc-internal data and is attached to it via
+ * opaque_ref.
+ */
+typedef struct FrameDecodeData {
+    /**
+     * The original user-set opaque_ref.
+     */
+    AVBufferRef *user_opaque_ref;
+} FrameDecodeData;
+
+/**
  * Called by decoders to get the next packet for decoding.
  *
  * @param pkt An empty packet to be filled with data.