Add mp3 gain as a DSP option

[TechVsLife]

Add mp3gain as DSP option.
Currently dMC has two main normalization options: (1) to alter the tag only (e.g. ReplayGain calculation), or (2) to alter the audio data irreversibly. Hardware players do not read or understand the ReplayGain tag. Hence we have to use the second method. But it would be better if there were a REVERSIBLE option of implementing the second method, so the user doesn't have to re-encode everything all over again if he wants to change the normalization, or just remove it.

mp3gain is reversible, and is understood by all mp3 hardware players:

See for example, from
http://www.hydrogenaudio.org/forums/...hp/t35635.html:

Mp3Gain does not really change the audiodata itself. An mp3 consists of "frames"(like sectors on a CD). Every of those frames has a preamp-modifier-variable. This modifier is stored in *addition* to the audiodata in the frame, and it can exceed the max volume. Thus, the modifier can be higher than the max volume and therefore can be reversed - if the undo-data is stored somewhere(mp3gain stores them in tags)

and from
http://forums.winamp.com/showthread.php?threadid=268933:

MP3gain IS reversible. It is correct that MP3gain modifies the MP3 frames, but it writes additional "Undo information" in some special metadata. So, with the MP3gain GUI, you can always restore the original state of the files.

Also:

http://www.hydrogenaudio.org/forums/lofiversion/index.php/t53492.html

[jtbse]

Re: Add mp3 gain as a DSP option

Can this be done with the "Run External" DSP? I haven't tried this myself, but MP3Gain does run from a command line, so I don't see why it wouldn't work.

Also...AFAIK, the option that you describe as "irreversibly" modifying things is really just Normalization (at least I think that's what you meant). Normalization doesn't really do the same thing that ReplayGain or MP3Gain does with "average volume". It only adjusts things based on the peaks. (apologies if you already understood that). :smile2:

[TechVsLife]

Re: Add mp3 gain as a DSP option

Good point: besides being reversible, mp3gain also has an approach better than peak normalization:

http://replaygain.hydrogenaudio.org/faq_norm.html

In that sense, it's an applied but reversible ReplayGain.

As far as running from a command line, yes, I could adjust all the command line options manually as needed, but that's the cumbersome old EAC approach--the point is that dMC makes everything easy to do, it might as well make this easy also. It could also make undoing the mp3gain easy. (I haven't tested it, so I don't know how well the external command option works with mp3gain.)

p.s. also might as well add aacGain, to do the equivalent with aac files:

http://www.rarewares.org/aac-encoders.php

Can this be done with the "Run External" DSP? I haven't tried this myself, but MP3Gain does run from a command line, so I don't see why it wouldn't work.

Also...AFAIK, the option that you describe as "irreversibly" modifying things is really just Normalization (at least I think that's what you meant). Normalization doesn't really do the same thing that ReplayGain or MP3Gain does with "average volume". It only adjusts things based on the peaks. (apologies if you already understood that). :smile2:

[LtData]

Re: Add mp3 gain as a DSP option

Note that AACGain is still in beta and, if it is added, won't be added until its final.

[TechVsLife]

Re: Add mp3 gain as a DSP option

Well, maybe 1.8 is in beta, but I think 1.7 is out and final (see the last link). Anyway, 1.6 is certainly final.

Note that AACGain is still in beta and, if it is added, won't be added until its final.

[LtData]

Re: Add mp3 gain as a DSP option

Whoops, I was reading about AACGain on the mp3Gain page, which hasn't been updated since 2005. You're right.

[TechVsLife]

Re: Add mp3 gain as a DSP option

Those pages do need to be updated, so I should send the author an email.

Whoops, I was reading about AACGain on the mp3Gain page, which hasn't been updated since 2005. You're right.