[LAU] keeping same perceived level on mp3 files

[Fons Adriaensen]

On Fri, Oct 05, 2012 at 07:12:00PM +0200, Georg Holzmann wrote:

> Do you just want to adjust the loudness between multiple files?
> (this means there is just a constant gain for every file so the they
> are similar on average)
> Or do you also want to change the loudness inside one track?
> 
> For case 1, you have to measure the loudness somehow (best way would
> be to use a loudness standard like used in EBU R128 - see https://auphonic.com/blog/2012/08/02/loudness-measurement-and-normalization-ebu-r128-calm-act/),
> and then you apply a constant gain, combined with a limiter (and
> maybe compressor) if the gain is positive.

Or use ebumeter (real-time, GUI) or ebur128 (batch processing).
The latter combined with some scripting and sox (or doing it
manually) will provide what you need.

Both available from:

   <http://kokkinizita.linuxaudio.org/linuxaudio/downloads>.

LAC paper on the theory behind this:

   <http://kokkinizita.linuxaudio.org/papers>

Ciao,

-- 
FA

A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)