[gstreamer-bugs] [Bug 619778] New: gstreamer fails to play certain files. I blame oggdemux failing on zero-length pages.

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=619778
  GStreamer | gst-plugins-base | 0.10.29

           Summary: gstreamer fails to play certain files.  I blame
                    oggdemux failing on zero-length pages.
    Classification: Desktop
           Product: GStreamer
           Version: 0.10.29
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-base
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: bens at alum.mit.edu
         QAContact: gstreamer-bugs at lists.sourceforge.net
      GNOME target: ---
     GNOME version: ---


gstreamer fails to demux the following file correctly:

http://ia331209.us.archive.org/0/items/Patent_Absurdity/Patent_Absurdity_HD_3540kbit.ogv

I discovered this when trying to execute the following pipeline:

gst-launch-0.10 filesrc location= /tmp/Patent_Absurdity_HD_3540kbit.ogv !
oggdemux name=demux ! theoradec ! queue ! videoscale method=2 !
video/x-raw-yuv,width=720,height=480 ! queue ! mpeg2enc format=8 aspect=3 !
mpegpsmux name=mux ! filesink location=/tmp/patents_out.mpg . demux. !
vorbisdec ! audioconvert ! queue ! twolame bitrate=320 ! mux.

This pipeline will hang after about a minute.  I believe it stops because
oggdemux is dropping zero-length pages (i.e. pages containing only zero-length
packets), leading to audio and video drifting apart.  I confirmed this
suspicion by running

gst-launch-0.10 filesrc location= /tmp/Patent_Absurdity_HD_3540kbit.ogv !
oggdemux name=demux ! theoradec ! queue ! videoscale method=2 !
video/x-raw-yuv,width=720,height=480 ! queue ! mpeg2enc format=9 bitrate=7000 !
mpegpsmux name=mux ! filesink location=/tmp/patents_out.m2v

i.e. re-encoding just the video.  The resulting m2v file is mostly complete,
but long perfectly still scenes in the ogv are greatly shortened in the m2v.

I suspect that this bug has not been observed previously because (1) real-time
decode happens to work anyway because the dropped frames don't affect display,
and (2) old versions of libogg were less likely to produce zero-length pages.

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