[FFmpeg-trac] #598(avformat:open): Subtitle on some BD/m2ts files are not handle.

FFmpeg trac at avcodec.org
Fri Mar 9 20:33:08 CET 2012

#598: Subtitle on some BD/m2ts files are not handle.
             Reporter:  Sebastiii    |                    Owner:  michael
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:  avformat
              Version:  git-master   |               Resolution:
             Keywords:  subtitle     |               Blocked By:
  m2ts pmt bluray                    |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |

Comment (by heleppkes):

 Instead of going the tedious parsing/auto detection route, i sat down and
 tried to find the issue in avformats MPEG-TS parsing.

 The root cause of the problem seems to be that the CRC in the PAT/PMT in
 those files is not correct. avformats mpeg-ts demuxer will just ignore any
 PAT/PMT which has a wrong CRC, while mplayers demuxer ignores the CRC

 In any case, i disabled the CRC check in avformat, and suddenly it finds
 all the streams just fine.
 The changes required are here:

 I'm not sure how many bad things can happen when the CRC is wrong, or how
 important that check is for broadcast content... i'll leave the checks
 disabled and see what happens. Nothing beats empirical evidence. :p

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/598#comment:13>
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