[FFmpeg-devel] [PATCH] avformat/mov: fix demuxing of eia-608

[Carl Eugen Hoyos]

Am So., 14. Juni 2020 um 14:22 Uhr schrieb Paul B Mahol <onemda at gmail.com>:
>
> Fixes #4616.
>
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
>  libavformat/mov.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 2fc27d2aec..6d83a8a4b3 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -7854,6 +7854,27 @@ static int mov_change_extradata(MOVStreamContext *sc, AVPacket *pkt)
>      return 0;
>  }
>
> +static int get_eia608_packet(AVIOContext *pb, AVPacket *pkt, int size)
> +{
> +    int new_size, ret;
> +
> +    if (size <= 8)
> +        return AVERROR_INVALIDDATA;
> +    new_size = ((size - 8) / 2) * 3;
> +    ret = av_new_packet(pkt, new_size);
> +    if (ret < 0)
> +        return ret;
> +
> +    avio_skip(pb, 8);
> +    for (int j = 0; j < new_size; j += 3) {
> +        pkt->data[j] = 0xFC;
> +        pkt->data[j+1] = avio_r8(pb);
> +        pkt->data[j+2] = avio_r8(pb);
> +    }
> +
> +    return 0;
> +}
> +
>  static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
>  {
>      MOVContext *mov = s->priv_data;
> @@ -7898,6 +7919,9 @@ static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
>              goto retry;
>          }
>
> +        if (st->codecpar->codec_id == AV_CODEC_ID_EIA_608 && sample->size > 8)
> +            ret = get_eia608_packet(sc->pb, pkt, sample->size);
> +        else
>          ret = av_get_packet(sc->pb, pkt, sample->size);

I have to repeat the question that I raised in the ticket:
Doesn't this patch break remuxing of the subtitle stream?

Thank you for looking into this issue!

Carl Eugen