avcodec: Add padding after the remaining AVFrames

This limits ABI issues in case libavcodec is linked to a libavutil with larger AVFrame
Which can happen if they are shiped in seperate binary packages and libavutil is upgraded

A cleaner alternative would be to replace them by pointers but this would likely cause
a small speedloss

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h264.h

@@ -289,6 +289,7 @@ typedef struct MMCO {
 
 typedef struct H264Picture {
     struct AVFrame f;
+    uint8_t avframe_padding[1024]; // hack to allow linking to a avutil with larger AVFrame
     ThreadFrame tf;
 
     AVBufferRef *qscale_table_buf;

libavcodec/mpegvideo.h

@@ -93,6 +93,7 @@ struct MpegEncContext;
  */
 typedef struct Picture{
     struct AVFrame f;
+    uint8_t avframe_padding[1024]; // hack to allow linking to a avutil with larger AVFrame
     ThreadFrame tf;
 
     AVBufferRef *qscale_table_buf;

libavcodec/utils.c

@@ -807,6 +807,7 @@ int avcodec_default_get_buffer(AVCodecContext *avctx, AVFrame *frame)
 typedef struct CompatReleaseBufPriv {
     AVCodecContext avctx;
     AVFrame frame;
+    uint8_t avframe_padding[1024]; // hack to allow linking to a avutil with larger AVFrame
 } CompatReleaseBufPriv;
 
 static void compat_free_buffer(void *opaque, uint8_t *data)