[FFmpeg-devel] [PATCH 2/2] avformat/mpegts: Skip over broken 0x80 headers

[Paul B Mahol]

On 4/10/16, Michael Niedermayer <michael at niedermayer.cc> wrote:
> This fixes demuxing of 01c56b0dc1.ts
>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavformat/mpegts.c |   12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c
> index e856ff0..38ff264 100644
> --- a/libavformat/mpegts.c
> +++ b/libavformat/mpegts.c
> @@ -2335,7 +2335,7 @@ static void reanalyze(MpegTSContext *ts) {
>
>  /* XXX: try to find a better synchro over several packets (use
>   * get_packet_size() ?) */
> -static int mpegts_resync(AVFormatContext *s, int seekback)
> +static int mpegts_resync(AVFormatContext *s, int seekback, const uint8_t
> *current_packet)
>  {
>      MpegTSContext *ts = s->priv_data;
>      AVIOContext *pb = s->pb;
> @@ -2344,6 +2344,12 @@ static int mpegts_resync(AVFormatContext *s, int
> seekback)
>
>      avio_seek(pb, -FFMIN(seekback, pos), SEEK_CUR);
>
> +    //Special case for files like 01c56b0dc1.ts
> +    if (current_packet[0] == 0x80 && current_packet[12] == 0x47) {
> +        avio_seek(pb, 12, SEEK_CUR);
> +        return 0;
> +    }
> +

Can this break valid files?

>      for (i = 0; i < ts->resync_size; i++) {
>          c = avio_r8(pb);
>          if (avio_feof(pb))
> @@ -2375,7 +2381,7 @@ static int read_packet(AVFormatContext *s, uint8_t
> *buf, int raw_packet_size,
>          if ((*data)[0] != 0x47) {
>              /* find a new packet start */
>
> -            if (mpegts_resync(s, raw_packet_size) < 0)
> +            if (mpegts_resync(s, raw_packet_size, *data) < 0)
>                  return AVERROR(EAGAIN);
>              else
>                  continue;
> @@ -2730,7 +2736,7 @@ static av_unused int64_t
> mpegts_get_pcr(AVFormatContext *s, int stream_index,
>          if (avio_read(s->pb, buf, TS_PACKET_SIZE) != TS_PACKET_SIZE)
>              return AV_NOPTS_VALUE;
>          if (buf[0] != 0x47) {
> -            if (mpegts_resync(s, TS_PACKET_SIZE) < 0)
> +            if (mpegts_resync(s, TS_PACKET_SIZE, buf) < 0)
>                  return AV_NOPTS_VALUE;
>              pos = avio_tell(s->pb);
>              continue;
> --
> 1.7.9.5
>
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