[Flac] flac --replay-gain

Martin Leese martin.leese at stanfordalumni.org
Wed Dec 30 12:18:59 PST 2009


Dat Head <dathead2 at gmail.com> wrote:

> can somebody explain replaygain a bit - is it kinda like normalization
> but w/o modifying
> the files (just giving software a number to use to obtain the level
> boost needed?)

Try http://www.replaygain.org/ although the
pages haven't been updated since 2001.  (In
the past I have e-mailed updates to the
maintainer, but got no response.)

> and how does track vs album gain work (doesn't seem like you could use
> both at same
> time if i'm at all understanding)

You are understanding.  From the FAQ:
<quote>
"Audiophile" Replay Gain adjustment

The problem with the "Radio" setting is that tracks which should be
quiet will be brought up to the level of all the rest. For casual
listening, or in a noisy background, this can be a good thing. For
serious listening, it would be a nuisance. You don't want a solo flute
track blasting at the same loudness as Iron Maiden!

To solve this problem, the "Audiophile" setting represents the ideal
listening gain for each track. ReplayGain can have a good guess at
this too, by reading the entire CD, and calculating a single gain
adjustment for the whole disc. This works because quiet tracks then
stay qui[e]ter than the rest, since the gain won't be changed for each
track. It still solves the basic problem (annoying, unwanted level
differences between discs) because quiet or loud discs are still
adjusted overall - so the pop CD that's 20 dB louder than the
classical CD will be brought into line.

Where ReplayGain will fail is if you have an entire CD of quiet music.
It will bring it up to an average level. This is why the "Audiophile"
Replay Gain adjustment must be user adjustable. The ReplayGain whole
disc value represents a good guess, and should be stored in the file.
Later, the user can tweak it if required.

If the file has originated from the artist (e.g. download from
mp3.com), then the "Audiophile" setting can be specified by the
artist. Naturally, the user is free to change the value if they
desire.
</quote>

Regards,
Martin
-- 
Martin J Leese
E-mail: martin.leese  stanfordalumni.org
Web: http://members.tripod.com/martin_leese/


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