Make volume normalisation Intelligent (Random/Sequential playback needs are different)

To make the volumes of 2 different songs sound the same, Songbird employs a technique known as normalisation/ReplayGain, and there are 2 types:

Track Gain: This works out the volume adjustments required for a single track, to make it sound the same as other files. Unfortunately, in a pre-mixed compilation, using this may result in volume jumps during track changes (because the song mixed into may be slightly louder).
Album Gain This works out the volume adjustments required for an entire album, to make it sound the same. Works great with premixed. Unfortunately, if half the album is really loud, the rest is really soft, it isn't normalised properly, and some songs will be too loud, and some too soft.

Album gain is only useful when playing files sequentially, because it only really helps to prevent volume jumps in between tracks which are premixed. In random playback, this doesn't happen, so it actually provides a worse experience.

I propose that Songbird should add a 3rd option, to automatically set Track gain when Shuffle is set, but to switch to Album gain when playing files in order. This offers the best experience overall to listeners...

Bug Suggestions:
http://bugzilla.songbirdnest.com/show...