[FFmpeg-trac] #8508(undetermined:new): mp4 - STSC entry 1 is invalid

[FFmpeg]

#8508: mp4 - STSC entry 1 is invalid
-------------------------------------+-------------------------------------
             Reporter:  jbagg        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 Some mp4 audio files are not readable.  Example attached.  If I comment
 out the invalid data error return in mov_read_trak() in libavformat/mov.c,
 the attached file plays without error.  Both VLC and win 10 builtin player
 can play the attached.  I tested with with ffmpeg versions head, 4.2 and
 3.6.  The attached file errors out on all 3 versions tested.

 {{{
 diff --git a/libavformat/mov.c b/libavformat/mov.c
 index 589576b..95d57e3 100644
 --- a/libavformat/mov.c
 +++ b/libavformat/mov.c
 @@ -4224,7 +4224,7 @@ static int mov_read_trak(MOVContext *c, AVIOContext
 *pb, MOVAtom atom)
      if (sc->stsc_count && sc->stsc_data[ sc->stsc_count - 1 ].first >
 sc->chunk_count) {
          av_log(c->fc, AV_LOG_ERROR, "stream %d, contradictionary STSC and
 STCO\n",
                 st->index);
 -        return AVERROR_INVALIDDATA;
 +//        return AVERROR_INVALIDDATA;
      }

      fix_timescale(c, sc);
 }}}


 How to reproduce:
 {{{
 ./ffprobe ../STSC_entry_1_is_invalid_13_Glass.m4a
 ffprobe version n4.2.2-1-g19bfd72126 Copyright (c) 2007-2019 the FFmpeg
 developers
   built with gcc 8 (Debian 8.3.0-6)
   configuration: --disable-shared --enable-static
   libavutil      56. 31.100 / 56. 31.100
   libavcodec     58. 54.100 / 58. 54.100
   libavformat    58. 29.100 / 58. 29.100
   libavdevice    58.  8.100 / 58.  8.100
   libavfilter     7. 57.100 /  7. 57.100
   libswscale      5.  5.100 /  5.  5.100
   libswresample   3.  5.100 /  3.  5.100
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x56431e165d80] STSC entry 1 is invalid
 (first=43 count=0 id=1)
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x56431e165d80] stream 0, contradictionary STSC
 and STCO
 [mov,mp4,m4a,3gp,3g2,mj2 @ 0x56431e165d80] error reading header
 ../STSC_entry_1_is_invalid_13_Glass.m4a: Invalid data found when
 processing input
 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8508>
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