After rewind matroska-files audio is disappear in VLC when using PulseAudio.
Audio is disappear in VLC not for few seconds but disappear at all. Easly reproduceable with this sample: http://www.mediafire.com/?u7yui0oiqd3c0bd
Reproduced in VLC 1.3.0 git20120109 from ppa:videolan/master-daily PPA on Kubuntu 11.10.
There is no such problems with avi or mp4 containers so probably related to demuxer.