http://code.google.com/p/webm/downloads/detail?name=webmdshow-0.9.11.0-20101207.zip
http://code.google.com/p/webm/downloads/list
A few of the changes for this release include:
makewebm can now merge audio from a file separate from video.
Support for alt-ref frames has been added.
VP8 encoder now uses latest release of vpx library ("Aylesbury").
Source and splitter filters now use the libwebm library to handle webm
file parsing.
Splitter now has partial support for timed reads from upstream
filter's IAsyncReader interface.
Parser now supports webm files that have laced frames.
Requirement that webm file has a duration (in the SegmentInfo) has been relaxed.