1. 01 Sep, 2012 1 commit
    • Philip Langdale's avatar
      matroskadec, matroskadec, srtenc: Read/Write duration for subtitles. · 9d89c8b3
      Philip Langdale authored
      After much discussion and back-and-forth, we reached the conclusion
      that matroska uses convergence_duration for subtitle duration because
      a 32bit value isn't large enough to store the duration if sub-micro-second
      timebases are used. Matroska may not be the only one that supports these
      timebases, but it's certainly the only one that ffmpeg attempts to support
      in this way.
      
      The long term solution that we seemed to reach was that if we encounter
      a matroska file with a sub-micro-second timebase, we should internally
      scale it up to at least micro-second, and then duration can be used
      normally. This suggests that on the encode side, we should not allow
      generation of files with sub-micro-second timebases, but that's a separate
      issue.
      
      That being a non-trivial change, and the subtitle interoperability breakage
      being very real, I'm re-submitting this small change for consideration.
      
      In this diff, we make sure that duration is populated by the matroska
      demuxer, and that convergence_duration is respected in matroskaenc and
      srtenc, but that duration is used otherwise. This ends up being a strict
      improvement - pipelines that use convergence duration are unchanged, and
      ones that are currently broken due to the duration mismatch will start
      working - except for the ones with the extreme timebases, but those were
      already broken.
      Signed-off-by: 's avatarPhilip Langdale <philipl@overt.org>
      9d89c8b3
  2. 31 Aug, 2012 33 commits
  3. 30 Aug, 2012 6 commits