Theora plays much worse in OGG than in MKV; only in VLC.

[yurb]

Dear VLC developers/users,

I'm still not 100% sure this is a bug in VLC and not in the encoding tools I use, but at this point VLC is the only player that has the problem described below.

Here's what happens. Let's take a source video, say a 720p ogg Big Buck Bunny and encode [a part of] it in three different ways:
1) ogg container, theora + vorbis; using

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avconv -i $SAMPLE -f ogg -codec:a libvorbis -t $SECONDS -aq 4 -codec:v libtheora -qscale:v 6 -y test-avconv.ogg

2) ogg container, theora + vorbis; using

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ffmpeg2theora $SAMPLE -e $SECONDS -v 6 -a 4 -o test-ffmpeg2theora.ogg

3) mkv container, theora + vorbis; using

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avconv -i $SAMPLE -f matroska -codec:a libvorbis -t $SECONDS -aq 4 -codec:v libtheora -qscale:v 6 -y test-avconv.mkv

In all the three cases the quality settings were left the same.

The result is that the samples No. 1 and 2 play equally "choppy" (noticeable and regular frame droppings) in VLC 2.0.6 on Gnu/Linux and Windows (different machines) compared to the sample No. 3 which plays fine in VLC.

All three samples play fine in mplayer, totem and the samples No. 1 and 2 play fine in Firefox and Chromium (they don't seem to support mkv so I can't test the third sample).

The funny thing is that the original source video is also theora in ogg container, but it plays without any problem in VLC. This makes me wonder what's wrong with the generated files so that they cause trouble to VLC but not to other players.

Version information of ffmpeg2theora:

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ffmpeg2theora 0.27 - Xiph.Org libtheora 1.1 20090822 (Thusnelda)

Version information of avconv:

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avconv version 0.8.6-6:0.8.6-1, Copyright (c) 2000-2013 the Libav developers built on Mar 24 2013 18:40:26 with gcc 4.7.2 avconv 0.8.6-6:0.8.6-1 libavutil 51. 22. 1 / 51. 22. 1 libavcodec 53. 35. 0 / 53. 35. 0 libavformat 53. 21. 1 / 53. 21. 0 libavdevice 53. 2. 0 / 53. 2. 0 libavfilter 2. 15. 0 / 2. 15. 0 libswscale 2. 1. 0 / 2. 1. 0 libpostproc 52. 0. 0 / 52. 0. 0

Any ideas?

EDIT: This behavior is also present in the vlc-2.0.7-20130505-0119 nightly (compiled from source on Debian amd64).