I have created an application to do local transcoding of audio and video uploaded to Moodle.
Some participants were unable to view files uploaded by others because of platform differences. Not everybody has QuickTime installed for .MOV and Ogg Vorbis audio recordings can't be played on iOS devices. Streaming through a third party service was not an option for privacy reasons.
The application I created, Mootranscode, converts those formats to MP4 and replaces references to the uploaded file with the transcoded file. It runs in the background and periodically scans for files to convert.
There currently is not an executable release but the source code can be found at