[gstreamer-bugs] [Bug 602936] New: Lipsync issue when converting mkv to mp4 using mp4mux h264/aac

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=602936
  GStreamer | gst-plugins-bad | git

           Summary: Lipsync issue when converting mkv to mp4 using mp4mux
                    h264/aac
    Classification: Desktop
           Product: GStreamer
           Version: git
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-bad
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: backha at gmail.com
         QAContact: gstreamer-bugs at lists.sourceforge.net
      GNOME target: ---
     GNOME version: ---


Created an attachment (id=148443)
 View: https://bugzilla.gnome.org/attachment.cgi?id=148443
 Review: https://bugzilla.gnome.org/review?bug=602936&attachment=148443

Thiago's use timestamp patch

With the current git version of gst-plugins-bad the following gst-launch line
will give an unsynced mp4 using a synched mkv:
gst-launch -v filesrc location=p.mkv ! matroskademux name=d mp4mux name=m !
filesink location=p.mp4 d.video_00 ! queue ! m.video_00 d.audio_00 ! queue !
m.audio_00

The sync issue was/is related to the way matroska uses durations. Durations are
constant and ts_now + duration != ts_next. This did cause problems in qtmux
which earlier always used durations.
Thiago sent me a patch (that is attached) that checks if the duration if the
timestamps are unordered. In all other cases the buffer timestamps are used.

During my muxtests the patch has shown a great improvement and three out of
four conversions works flawless and the video/audio is synced. But there is
still one clip that fails for some reason. The clip is available here:

http://bachman.rxtx.se/tmp/muxtest/p.mkv (synced matroska)
http://bachman.rxtx.se/tmp/muxtest/p.mp4 (unsynced mp4muxed mp4)

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