codecs

In the "about BSplayer", the various file formats are shown. But there is also the comment " some file formats may require additional codecs. Why isn't this more specific? Why doesn't the comment say which formats need which codacs and where the codecs can be obtained ? I have downloaded and installed BSplayer and tried to play a videoCd. It won't play - I get the comment " can't play file format DIV3". Do I need a codec? Where do I get it from?