ffmpeg2theora is a simple converter to create Ogg-Theora files.  It currently
provides only command-line interface to convert any files that ffmpeg
can decode.

Dependencies include:
1. ffmpeg (available at SBo) 
2. libtheora (available in Slackware 12.2)
3. scons (available at SBo, required for building ffmpeg2theora)
4. libkate (available at SBo, required for subtitles support)

For usage, see man page.