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

[Carl Eugen Hoyos]

Am So., 14. Juni 2020 um 17:08 Uhr schrieb Paul B Mahol <onemda at gmail.com>:
>
> On 6/14/20, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> > 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!
>
> Do you have files that previously worked when being muxed by ffmpeg into mov?
> Thats is only scenario that no longer works, old invalid ffmpeg
> generated mov files.
> I guess similar patch should be done for mov muxer. If not already.

(hard to parse)

That was my question:
Once remuxing is fixed on the muxer side, will your patch still allow
remuxing at all?

Carl Eugen