[ excerpt (with adaptations) from developer's website with modifications ]

These tools allow information about (ogminfo) or extraction from
(ogmdemux) or creation of (ogmmerge) OGG media streams. Note that
I'll use OGM for "OGG media streams".

Supported stream types include video streams from AVIs or Ogg files
and Vorbis audio from Ogg files. The resulting files can be played
back with mplayer or with the OggDS Direct Show filters under
Windows.

WWW: http://www.bunkus.org/videotools/ogmtools/