1 Some songs are louder than others, and it's annoying to have to
2 constantly tweak the volume knob to keep things at a reasonable level.
3 Enter "replay gain". You use a tool to go through your music and add
4 tags marking how loud each song/album is, then you play them with
5 something that understands the tags and adjusts the volume for you.
6 Very convenient. Robert Downes (Bobulous) has a [nice post with
7 scripts for tagging FLAC files][post] (the heart of his scripts is
8 `metaflac --add-replay-gain *.flac`). Then just add
12 to `/etc/mpd.conf` and restart [[mpd]]. VoilĂ !
14 If you're not using `mpd`, modern versions of [flac][] come with an
15 undocumented `--apply-replaygain-which-is-not-lossless` option. It's
16 annoying that they haven't gotten around to documenting this option
17 (since 2004!), but the syntax itself is pretty simple (description
18 from [this post][syntax]):
20 --apply-replaygain-which-is-not-lossless[=<specification>]
22 where `<specification>` has the format:
24 [<preamp>][a|t][l|L][n{0|1|2|3}]
26 <preamp> Floating point dB to add to the existing gain.
27 a|t Album (a) or track (t) gain.
28 l|L Peak-limit (l) or 6dB hard limiter (L)
29 n{0|1|2|3} Noise shaping from none (0) to strong (3) when
30 dithering back to integer amplitudes.
32 The default is `0aLn1`. If you look in the `flac` source, this
33 documentation is in `doc/html/documentation_tools_flac.html` (where it
36 [post]: http://www.bobulous.org.uk/misc/Replay-Gain-in-Linux.html
37 [flac]: http://flac.sourceforge.net/
38 [syntax]: http://www.hydrogenaudio.org/forums/index.php?showtopic=17293&pid=171075&mode=threaded&start=#entry171075