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Topic: Gain: analysis+apply OR analysis only? (Read 2139 times) previous topic - next topic

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  • Azevedo
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Gain: analysis+apply OR analysis only?
Hey

I'm using mp3gain / aacgain and I was wondering whether I should apply the gain after analysis or leave the mp3/mp4 ONLY with the analysis TAG, even though the opperation is lowssless.

I wonder that because on flac format, foobar2k will only make analysis, the volume correction is done during the playback according to each files tagged volume analysis. (correct me here if I'm wrong, please)

Now, besides Foobar2k, I also use AIMP3 player, Winamp and iPod to play those mp3/4. Will these players read the gain or just play the plain stream as it is?


Thanks!


  • mjb2006
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Gain: analysis+apply OR analysis only?
Reply #1
If you're going to play the MP3 &AAC files on devices that don't support ReplayGain, and...
you want them to have the adjusted volume, and...
you don't mind modifying the files (fb2k doesn't save undo info)...
then you might want to go ahead and apply the gain.

Of the players you listed, only iPods (with default firmware) don't support ReplayGain. So that might be reason enough for you to apply the gain.

Some iPods (not my Shuffle though) support Sound Check, which is Apple's equivalent to ReplayGain. According to their docs, you have to use iTunes to create the files in order to get the right tags; otherwise it just stores the info in the iTunes database, which might not do you any good when the songs are copied to the iPod. You can also search for info about converting ReplayGain tags to ITUNNORM tags.
  • Last Edit: 24 January, 2013, 12:17:29 AM by mjb2006

  • azaqiel
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Gain: analysis+apply OR analysis only?
Reply #2
I'm not sure what to respond to, so I'll just throw everything out there.

the operation of applying gain to audio data (as far as I can tell) is NOT lossless.  tagging, however, is lossless.

the mp4 tagging system doesn't allow for ReplayGain or R128 gain, but does apparently allow for SoundCheck.  I believe that foobar2000 adds gain tags to mp4 files as APEv2 tags, not the proprietary tags that iPod reads.

I've never used AIMP3, and have not recently used Winamp, but the iPod with Apple firmware will not read APEv2 tags.  it might read APEv2 tags from mp3s, though.

"analysis only" means that you're only analyzing the files, not adding tags or changing the audio data.  "applying" might mean either adding tags or changing the audio, if I remember correctly.

  • saratoga
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Gain: analysis+apply OR analysis only?
Reply #3
the operation of applying gain to audio data (as far as I can tell) is NOT lossless.  tagging, however, is lossless.


Its lossless in that it can be completely reversed without loss of information.  Obviously if you play the file back at a lower level, the volume won't be the same.  The data however is not lost.

  • nu774
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Gain: analysis+apply OR analysis only?
Reply #4
And this is incorrect, too:
the mp4 tagging system doesn't allow for ReplayGain or R128 gain, but does apparently allow for SoundCheck.  I believe that foobar2000 adds gain tags to mp4 files as APEv2 tags, not the proprietary tags that iPod reads.