From MythTV Official Wiki
- MythMusic: Loudness equalisation. A music collection often contains recordings which have different loudnesses, which can lead to unpleasant differences when played on shuffle etc. A menu option to enable loudness equalisation would be great.
- MP3s often, but not always, have embedded Replay Gain metadata about loudness which can help with this. I don't know if this is currently supported in mythmusic but I would imagine that would probably be the first step if not. Other files such as WAVs don't have this information - so a general solution would probably involve a low-priority cron job or suchlike, which analysed the files to determine their loudness / replaygain.