MediaCoder offers an alternative way. Why should we install new codecs when we can transform the ones used by the video? And that's what it does. Furthermore, when it changes the codecs it powers up the quality of the video itself.
MediaCoder includes all the Open Source codecs that exist nowadays, so it's difficult to find a video that can't be converted by this really good tool.
MP3, OGG, RealAudio, WAV, AVI, MPEG, MOV, WMV... don't worry, you'll be able to watch and listen to all of them.