Re: Why is ReplayGain's Album gain tag necessary?
Reply #2 –
But is the result of that method significantly different to just getting the largest loudness gain value of a track from that album, and applying that to all the tracks?
The "gain" is not the "peak". The album "peak" works like you describe. The "gain" is akin to a weighted average loudness.
If you include one more track that does not have as loud a peak, album peak does not change, but album gain (typically) does.
So is there any point to separately concatenating, calculating and storing an album gain?
Yes. Unless you want volume to boost up at track transitions within the same album - say you listen to a live album, then what? Most of us want to keep album volume constant if we listen to an album. That is why we have the album tags. If you play just single tracks one from each album, then you probably want the track gains.
If you have a "various artists" sampler, then maybe you don't want that particular album to have album gain/peak. Then you don't need to scan as album - and if you already did, you can delete the album gain and album peak tags later.