[FFmpeg-devel] [PATCH] avformat/mxfenc: add h264_mp4toannexb bitstream filter if needed when muxing h264

[Andreas Rheinhardt]

Marton Balint:
> Partially fixes ticket #10395.
> 
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  libavformat/mxfenc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/libavformat/mxfenc.c b/libavformat/mxfenc.c
> index 61ed6fc3db..adc31c1cf4 100644
> --- a/libavformat/mxfenc.c
> +++ b/libavformat/mxfenc.c
> @@ -3542,6 +3542,16 @@ static int mxf_interleave(AVFormatContext *s, AVPacket *pkt,
>      return mxf_interleave_get_packet(s, pkt, flush);
>  }
>  
> +static int mxf_check_bitstream(AVFormatContext *s, AVStream *st, const AVPacket *pkt)
> +{
> +    if (st->codecpar->codec_id == AV_CODEC_ID_H264) {
> +        if (pkt->size >= 5 && AV_RB32(pkt->data) != 0x0000001 &&
> +                              AV_RB24(pkt->data) != 0x000001)
> +            return ff_stream_add_bitstream_filter(st, "h264_mp4toannexb", NULL);
> +    }
> +    return 1;
> +}
> +
>  #define MXF_COMMON_OPTIONS \
>      { "signal_standard", "Force/set Signal Standard",\
>        offsetof(MXFContext, signal_standard), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 7, AV_OPT_FLAG_ENCODING_PARAM, .unit = "signal_standard"},\
> @@ -3623,6 +3633,7 @@ const FFOutputFormat ff_mxf_muxer = {
>      .p.flags           = AVFMT_NOTIMESTAMPS,
>      .interleave_packet = mxf_interleave,
>      .p.priv_class      = &mxf_muxer_class,
> +    .check_bitstream   = mxf_check_bitstream,
>  };
>  
>  const FFOutputFormat ff_mxf_d10_muxer = {
> @@ -3656,4 +3667,5 @@ const FFOutputFormat ff_mxf_opatom_muxer = {
>      .p.flags           = AVFMT_NOTIMESTAMPS,
>      .interleave_packet = mxf_interleave,
>      .p.priv_class      = &mxf_opatom_muxer_class,
> +    .check_bitstream   = mxf_check_bitstream,
>  };

I sent the very same patch long ago [1]. Tomas Härdin opposed it [2],
[3], because he sees stuff like this as hack.

- Andreas

[1]: https://ffmpeg.org/pipermail/ffmpeg-devel/2021-November/287638.html
[2]: https://ffmpeg.org/pipermail/ffmpeg-devel/2021-November/287702.html
[3]: https://ffmpeg.org/pipermail/ffmpeg-devel/2021-November/287703.html