MediaCoder is a different way to view those media files you can't. Usually, what people do is to install new codecs and their usual media player support the videos after that installation, but this time we are going to change the process.
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.