Re: [Bug-gnupod] Patch to support ReplayGain / mp3gain

[Richard van den Berg]

On 5/9/09 4:41 PM, H. Langos wrote:
> Well, the gain is given in dB relative to a reference level that most times
> is 83dB (But sometimes might be 89dB. The nasty details are here:
> http://www.mars.org/mailman/public/mad-dev/2004-February/000993.html )
> I assume that mp3gain uses 83dB. But it wouldn't hurt to check.
>   

From that URL:

> reached the conclusion that as the vast majority of
> implementations are using 89dB, we should take this infortunate
> situation into consideration and update the standard to 89dB

Since you already came to the conclusion that mp3gain is about the only 
implementation of the Replay Gain algorithm, I'm sure it uses 89dB as 
well. From mp3gain.c:

> /* the TAG version of the suggested Track Gain should ALWAYS be based 
> on the 89dB standard.
>    So we don't modify the suggested gain change until this point */

So I guess it is safe to store Replay Gain info inside RVA2 tags. The 
more I think about it, the more it makes sense to use the nid3lib code 
from normalize to make mp3gain support ID3 tags. I might attempt this 
when I have some free time (it could be a while until that happens).

Cheers,

Richard