With the advent of HTML 5 and it being adopted by almost all of the famous browsers, there is very good chance that the popular video format of the web over the next few years can move away from the proprietary formats to open vorbis format.
I am once again bewildered by the capabilities that ffmpeg brings to the desk. Almost most of the popular web video formats can be converted to ogg theora / vorbis in a jiffy
ffmpeg -i input.flv -acodec vorbis -ac 2 -vcodec theora -f ogg output.ogv
The above command converts an flv into ogv file using the audio codec vorbis and video codec libtheora.
Very simple isn’t it