[FFmpeg-devel] [PATCH 1/2] avcodec/decode: inject missing global side data to output frames

[Andreas Rheinhardt]

James Almer:
> ff_decode_frame_props() injects global side data passed by the caller (Usually
> coming from the container) but ignores the global side data the decoder
> gathered from the bitstream itself.
> This commit amends this.
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/decode.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/libavcodec/decode.c b/libavcodec/decode.c
> index cac7e620d2..c5a577f4f1 100644
> --- a/libavcodec/decode.c
> +++ b/libavcodec/decode.c
> @@ -1570,6 +1570,15 @@ int ff_decode_frame_props(AVCodecContext *avctx, AVFrame *frame)
>      if (ret < 0)
>          return ret;
>  
> +    for (int i = 0; i < avctx->nb_decoded_side_data; i++) {
> +        const AVFrameSideData *src = avctx->decoded_side_data[i];
> +        if (av_frame_get_side_data(frame, src->type))
> +            continue;
> +        ret = av_frame_side_data_clone(&frame->side_data, &frame->nb_side_data, src, 0);
> +        if (ret < 0)
> +            return ret;
> +    }
> +
>      if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SETS_FRAME_PROPS)) {
>          const AVPacket *pkt = avctx->internal->last_pkt_props;
>  

Why is this attached to every frame instead of just the first one?
If I read this correctly, it will be possible for there to be
decoded_side_data propagated to the output, then in-stream side-data of
the same type (not overridden) and in the next frame, the decoder adds
the decoded_side_data again, presuming that the side data from the
earlier frame was meant to be non-persistent.

- Andreas