[FFmpeg-devel] [FFmpeg-cvslog] ffmpeg: pass first video AVFrame's side data to encoder

[Anton Khirnov]

Quoting Jan Ekström (2024-03-20 18:31:49)
> ffmpeg | branch: master | Jan Ekström <jeebjp at gmail.com> | Mon Jan  9 20:52:30 2023 +0200| [8f4b173029aa9ecefb1370c954ef769664920d08] | committer: Jan Ekström
> 
> ffmpeg: pass first video AVFrame's side data to encoder
> 
> This enables further configuration of output based on the results
> of input decoding and filtering in a similar manner as the color
> information.
> 
> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8f4b173029aa9ecefb1370c954ef769664920d08
> ---
> 
>  fftools/ffmpeg_enc.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/fftools/ffmpeg_enc.c b/fftools/ffmpeg_enc.c
> index c9a12af139..f01be1c22f 100644
> --- a/fftools/ffmpeg_enc.c
> +++ b/fftools/ffmpeg_enc.c
> @@ -246,6 +246,21 @@ int enc_open(void *opaque, const AVFrame *frame)
>          enc_ctx->colorspace             = frame->colorspace;
>          enc_ctx->chroma_sample_location = frame->chroma_location;
>  
> +        for (int i = 0; i < frame->nb_side_data; i++) {
> +            ret = av_frame_side_data_clone(
> +                &enc_ctx->decoded_side_data, &enc_ctx->nb_decoded_side_data,
> +                frame->side_data[i], AV_FRAME_SIDE_DATA_FLAG_UNIQUE);

I objected to this indiscriminate copying in a previous review.

There is no reason to expect side data to apply to the whole stream just
because it happens to apply to the first frame. For many side data types
it does not even make sense, as they are fundamentally per-frame.

-- 
Anton Khirnov