Encodebin transcoding from MKV to MPEG2 fails

[Jens Georg]

We received an upstream bug about failing transcoding of MKV files to MPEG2:

Rygel-CRITICAL **: Error from pipeline RygelHTTPGstResponse:
matroska-demux.c(4492): gst_matroska_demux_loop ():
/GstPipeline:RygelHTTPGstResponse/GstBin:transcoder-source/GstDecodeBin2:decodebin2/GstMatroskaDemux:matroskademux0:
stream stopped, reason not-negotiated
0:00:27.875964071 6327 0x2516010 DEBUG mpegtsmux
mpegtsmux.c:1047:mpegtsmux_release_pad:<muxer> Pad <muxer:sink_65> being
released
0:00:27.885447062 6327 0x2516010 DEBUG mpegtsmux
mpegtsmux.c:1047:mpegtsmux_release_pad:<muxer> Pad <muxer:sink_64> being
released

Rygel-CRITICAL **: Error from pipeline RygelHTTPGstResponse:
matroska-demux.c(4492): gst_matroska_demux_loop ():
/GstPipeline:RygelHTTPGstResponse/GstBin:transcoder-source/GstDecodeBin2:decodebin2/GstMatroskaDemux:matroskademux1:
stream stopped, reason not-negotiated

https://bugzilla.gnome.org/show_bug.cgi?id=672439

The issue can only be reproduced on precise, I cannot make it fail on a self-compilied GStreamer stack with the same versions as in the mentioned bug report or on debian unstable.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: libgstreamer0.10-0 0.10.36-1
ProcVersionSignature: Ubuntu 3.2.0-19.30-generic-pae 3.2.11
Uname: Linux 3.2.0-19-generic-pae i686
ApportVersion: 1.94.1-0ubuntu2
Architecture: i386
Date: Tue Mar 20 14:39:49 2012
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta i386 (20120301)
ProcEnviron:
 TERM=xterm
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: gstreamer0.10
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Jens Georg (yg-jensge)]

With the syncing of rygel-0.14 to universe this is kind-of important now as it basically breaks transcoding completely.

[Jens Georg (yg-jensge)]

Actually the issue is the transcoding to mpeg. The reason seems that in contrast to upstream, the mpeg2enc plugin and the ffenc_mpeg2video habe the same rank secondary; encodebin seems to select the mpeg2enc plugin then which causes the issue. Moving /usr/lib/gstreamer-0.10/libgstmpeg2enc.so out of the way makes transcoding work again.