Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: unique, automatically loaded EQ for each song
From: Chris Holt (amiga2k_at_cox.net)
Date: 2003-09-30


On Tue, 30 Sep 2003 17:10:19 +0100, mrlipring wrote:
> doesn't that involve reencoding though?
>
>
> either way, it involves changing the file itself. you can't listen to a
> song in a global playlist, normalised, then decide you want to listen
> to that album, with each song in its original volume context (can't
> think of the proper way to say that, but you get me).
>
> We need to be able to store something in an extended id3v2 tag that
> holds the normalisation info. Even if it involved running an external
> app over the files once, then rockbox reads this extra tag, that'd be
> excellent.

No, this is not true. MP3Gain changes the global gain variable in each
frame of the MP3. It does not alter the audio information in any way and
the process is reversible. (easily so as the original values can be saved
from the software). Alternatively, one could only alter the files on the
device and leave the ones on the computer at their original levels.

Note also that MP3Gain does both file by file and album normalization. In
album mode, each tracks gain is adjusted relative to the others,
especially useful for generes like classical where some passages are
supposed to sound quieter than others.

Even in file by file mode, the default for MP3Gain is to adjust levels
based on percieved loudness rather than just the highest peak, so a
particularly loud note will not cripple it's ability to adjust gain for
the rest of the track. Also in every case the user is warned if the
requested level will cause clipping in the music. (file info turns red)

Chris



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa