Flac - Apr 2009 - track vs album replaygain: strange values

Hello,

I have experienced some quite strange with the "replaygain"
option after i had invoked FLAC over a set of files:

1. the TRACK_PEAK value is the same from the 3 tracks
and equal to the ALBUM_PEAK

2. the TRACK_GAIN values happen to be either above or below
(and never equal to) the ALBUM_GAIN value.

I can reproduce this ad lib (see example below), so this is a bug.

Or did i miss something ?

Please tell me if i am right -- if the "REPLAYGAIN_ALBUM_*" values
are supposed to be the maximum (or minimum) of the REPLAYGAIN_TRACK_*
values over all tracks.

# flac --replay-gain *.wav
# for f in *.flac; do echo "\n$f";  metaflac --export-tags-to= - $f;
done

e512100f_00.flac
REPLAYGAIN_REFERENCE_LOUDNESS=89.0 dB
REPLAYGAIN_TRACK_GAIN=-8.58 dB
REPLAYGAIN_TRACK_PEAK=0.99996948
REPLAYGAIN_ALBUM_GAIN=-8.31 dB
REPLAYGAIN_ALBUM_PEAK=0.99996948

e512100f_01.flac
REPLAYGAIN_REFERENCE_LOUDNESS=89.0 dB
REPLAYGAIN_TRACK_GAIN=-8.62 dB
REPLAYGAIN_TRACK_PEAK=0.99996948
REPLAYGAIN_ALBUM_GAIN=-8.31 dB
REPLAYGAIN_ALBUM_PEAK=0.99996948

e512100f_11.flac
REPLAYGAIN_REFERENCE_LOUDNESS=89.0 dB
REPLAYGAIN_TRACK_GAIN=-7.35 dB
REPLAYGAIN_TRACK_PEAK=0.99996948
REPLAYGAIN_ALBUM_GAIN=-8.31 dB
REPLAYGAIN_ALBUM_PEAK=0.99996948

It's possible that the peak actually is the same, thus the _PEAK  
reports you're getting reflects the actual values.

The calculated gain is an average.  There is no guarantee that the  
average for one track will be above or below the average for the  
album.  That's simple mathematics.

Brian Willoughby
Sound Consulting


On Apr 20, 2009, at 10:21, porte64 at free.fr wrote:
> 1. the TRACK_PEAK value is the same from the 3 tracks
> and equal to the ALBUM_PEAK
>
> 2. the TRACK_GAIN values happen to be either above or below
> (and never equal to) the ALBUM_GAIN value.
>
> I can reproduce this ad lib (see example below), so this is a bug.
>
> Or did i miss something ?
>
> Please tell me if i am right -- if the "REPLAYGAIN_ALBUM_*"
values
> are supposed to be the maximum (or minimum) of the REPLAYGAIN_TRACK_*
> values over all tracks.