Ffmpeg2theora is not a part of
ffmpeg, but an independent frontend for converting any format that ffmpeg can read into the free Ogg Vorbis audio and Ogg Theora video codecs.
ffmpeg2theora is straightforward and takes some of the guesswork out of media conversion
Like ffmpeg itself, ffmpeg2theora happens in the shell, so it is easily used in scripts and bulk actions.
ffmpeg2theora does not do anything that ffmpeg itself cannot do.
There may be no real advantage to using ffmpeg2theora over using ffmpeg directly, but it does have an abbreviated set of options since its goal is more focused than the near-infinite possibilities of ffmpeg.
For some video (especially high-res video meant to be dynamically scaled on any variety of device with any variety of screen size), consider trying, directly through ffmpeg, the
xvid formats, which are also free and open source like Theora.
The command structure is similar, so if you've used ffmpeg or mencoder to transcode media then it will all feel very familiar:
$ ffmpeg2theora input_file.avi -x 1920 -y 1080 -V 21000kbps -A 320kbps -c 2 -H 44100 -o output.ogv
Which breaks down to:
$ ffmpeg2theora [input filename] \ -x [target horizontal pixel count] \ -y [target vertical pixel count] \ -V [target bitrate in kbps] \ -A [audio bit rate] -c [audio channels] \ -H [audio sample rate in Hz] \ -o [output filename]
Ffmpeg2theora is available from http://slackbuilds.org and requires no special compile options.