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

FFmpeg trac at avcodec.org
Wed Feb 29 23:28:25 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 Andrea3000):

 Replying to [comment:7 cehoyos]:
 > I see three different problems with the BD stream you provided:
 > First, subtitle streams (0x120x) start late and are not detected by
 ffmpeg -i. The same happens for the DVD stream. Since (subtitle) streams
 can start at any point while playing back, but not every user wants a
 whole file to be scanned when starting ffmpeg, I do not think there is an
 easy solution. Note that the DVD stream plays as expected with mplayer
 -demuxer lavf -sid 0 (and ffplay with "t").
 > At least ffmpeg -analyzeduration 2000000000 -i stream and ffplay stream
 -sst 0 should work, both currently fail.
 > The second problem is that for the given BD sample, no streams are
 detected by the MPEG-TS demuxer, all have to be auto-detected (note the
 missing codec_tag information for the found streams in the output of
 ffmpeg -i). Since mplayer -demuxer mpegts works fine (it does not support
 auto-detection of video streams except MPEG-2), there seems to be a bug in
 FFmpeg's demuxer (not a regression, afaict). If you cut the sample so the
 subtitle streams start near the beginning of the file, subtitles are only
 shown as "Data: [0][0][0][0] / 0x0000".
 > I worked around this problem with attached patch (autodetection of BD
 subtitles), it works fine with mplayer -demuxer lavf -sid 0, but probably
 has a significant performance impact (at the moment the stream starts).
 > The third problem is that the BD subtitles are only shown for one frame
 by ffplay if you use the patch. I suspect this will not hit you when using
 third party applications (it cannot be reproduced with MPlayer), but is
 still noteworthy.

 I have the same issue with PGS subtitles not been detected but the
 provided patch didn't work.
 Is there any following with this problem?

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/598#comment:9>
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