This addon includes several additional codecs that are missing something - perhaps a good code review, some documentation, a set of tests, a real live maintainer, or some actual wide use. However, they might be good enough to play your media files.

These codecs can be used to encode and decode media files where the format is not patent encumbered.

A codec decodes audio and video for for playback or editing and is also used for transmission or storage. Different codecs are used in video-conferencing, streaming media and video editing applications.