I noticed that --replay-gain appears to add 'album gain' and 'album peak' data to re-encoded files (was using Synthetic Soul's batch @ this thread) but each of the files album and track gains were the same:

After re-encoding: Before Re-encoding:

How is this supposed to work? and more importantly, how is album gain supposed to be done correctly?

or is that not possible via command line since the encoder is only working with indvidual files?

and if thats true, then why is the encoder adding album gain tags for something it doesn't know about?

If you run --replay-gain on one file at a time, it will tag it with the track gain and the album gain, but since you've only selected one file, they'll be the same, right?

run "metaflac --replay-gain file1.flac file2.flac file3.flac ..." to make them all part of the same album. Make sense?

make sense?

OK, yeah that makes more sense, but I would expect that flac should not be adding album gains on single files...

Thanks for the reply.

Album gain on single files makes sense in conjunction with a decoder that's set only to care for the album gain information. Not every decoder falls back to track gain if no album gain value is found, at least that's the impression I have from certain Winamp 3rd party input plugins. For that reason I scanned my complete collection only with album gain.

Is it possible to adjust the reference-loudness in replay-gain for flac?
The standart is 89.0 dB.

I mean any command line!

On flac.sourceforge.net I can't find any documentation about this option being present, but there's no need for it anyway. ReplayGain-compatible players usually also offer a preamp which performs the desired volume adjustment on the decoding side. In Winamp it's in the equalizer window, the bar on the left, foobar2000 holds it in its playback options.

But, what if preamp is not possible? So there is no option at the moment?

@Josh
Maybe you could include a option to change the reference loudness in your next flac release?