Merge commit '5b145290df2998a9836a93eb925289c6c8b63af0'

* commit '5b145290df2998a9836a93eb925289c6c8b63af0':
  lavc: Add support for increasing hardware frame pool sizes

Merged-by: Mark Thompson <sw@jkqxz.net>

libavcodec/avcodec.h

@@ -3255,6 +3255,20 @@ typedef struct AVCodecContext {
      * (with the display dimensions being determined by the crop_* fields).
      */
     int apply_cropping;
+
+    /*
+     * Video decoding only.  Sets the number of extra hardware frames which
+     * the decoder will allocate for use by the caller.  This must be set
+     * before avcodec_open2() is called.
+     *
+     * Some hardware decoders require all frames that they will use for
+     * output to be defined in advance before decoding starts.  For such
+     * decoders, the hardware frame pool must therefore be of a fixed size.
+     * The extra frames set here are on top of any number that the decoder
+     * needs internally in order to operate normally (for example, frames
+     * used as reference pictures).
+     */
+    int extra_hw_frames;
 } AVCodecContext;
 
 #if FF_API_CODEC_GET_SET