lavc: Add device context field to AVCodecContext

For use by codec implementations which can allocate frames internally.

1 files changed, 23 insertions, 1 deletions

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 3e161ea10e..5616fb01d6 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -3536,7 +3536,8 @@ typedef struct AVCodecContext {
     /**
      * A reference to the AVHWFramesContext describing the input (for encoding)
      * or output (decoding) frames. The reference is set by the caller and
-     * afterwards owned (and freed) by libavcodec.
+     * afterwards owned (and freed) by libavcodec - it should never be read by
+     * the caller after being set.
      *
      * - decoding: This field should be set by the caller from the get_format()
      *             callback. The previous reference (if any) will always be
@@ -3586,6 +3587,27 @@ typedef struct AVCodecContext {
      */
     int64_t max_pixels;
 
+    /**
+     * A reference to the AVHWDeviceContext describing the device which will
+     * be used by a hardware encoder/decoder.  The reference is set by the
+     * caller and afterwards owned (and freed) by libavcodec.
+     *
+     * This should be used if either the codec device does not require
+     * hardware frames or any that are used are to be allocated internally by
+     * libavcodec.  If the user wishes to supply any of the frames used as
+     * encoder input or decoder output then hw_frames_ctx should be used
+     * instead.  When hw_frames_ctx is set in get_format() for a decoder, this
+     * field will be ignored while decoding the associated stream segment, but
+     * may again be used on a following one after another get_format() call.
+     *
+     * For both encoders and decoders this field should be set before
+     * avcodec_open2() is called and must not be written to thereafter.
+     *
+     * Note that some decoders may require this field to be set initially in
+     * order to support hw_frames_ctx at all - in that case, all frames
+     * contexts used must be created on the same device.
+     */
+    AVBufferRef *hw_device_ctx;
 } AVCodecContext;
 
 AVRational av_codec_get_pkt_timebase         (const AVCodecContext *avctx);