Ogg is an open source multimedia container format (why open source formats are a Good Idea). Ogg/Vorbis is popular for encoding audio, and Ogg/Theora/Vorbis is popular for encoding video.

You can easily record desktop tutorials encoded in Ogg/Theora/Vorbis using recordMyDesktop (see my screen recording post for details). However, sometimes your recording ends up with a bit of cruft at the ends that you want to crop out. Enter oggz, a simple tool for minor Ogg stream editing.

For example, you can quickly extract the first 657 seconds of a video with

$ oggz chop -e 657 -o output.ogv input.ogv

You can then add comments using vorbiscomment from the vorbis-tools package.

$ vorbiscomment -a input.ogv -t "ARTIST=Some Guy" -t "TITLE=A Title"