How To Use Mp3 Gain ?, 3 guides - normalization - maximizing Options

[user]

Last update:
2004-08-16


Thanks to westgroveg, we have a brief summary of today's possibilities:

This thread is always coming backup so here a few extra hints for users

• Album analyses  calculates track/album values so performing an album analyses is all you need to do.
  
  
  
  
  
  
• MP3Gain now supports writing changes to ID3 tag so it is 100% lossless, ie. completely reversible.
  
  
  
  
  
  
• As of LAME 3.96 (track) replaygain values are automatically written to the lame tag,
  
  
  
  
  
  
• Unlike MP3Gain, values stored in the lame tag need to be applied during playback which requires more CPU processing & the decoder to be aware.
  
  
  
  
  
  
• Foobar can automatically scan & adjust replaygain values without any need for MP3Gain but of course some of us don’t like this audio player.
  
  
  
  
  
• One more thing, make sure, you tag before using replaygain or instead of your replaygain values being hidden they appear in the comment field for some reason which can be annoying.

This post has been edited by user: Aug 20 2004, 11:33

[AreteOne]

with 2): For the very reason you mentioned: I want an exact reproduction, in terms of silences and even hiss (it can add that special flavor, think old jazz records). Silence is encoded at 32 kbps, in MPC even lower, so there's no problem.

I understand your perspective. For me, the silence issue is one of not wanting a bunch of seconds of silence on the front or back end of the track. For instance, the first song on the Counting Crows debut album has something like 14 seconds of silence. That's great for effect when looking at the album as an artistic entity, but if I add that track to a mix MP3 disc and play it in shuffle mode, everyone's going to wonder why the player quit working. It's not a file size thing, but rather a mixing thing. When I burn my own mix CDs, one of the important parts is deciding how much silence to put between each track - some tracks have little to none; I want them them to blend together while others needs more silence for the effect I want to communicate. As for the hiss, I should be clear that I'm only talking about the hiss at the very end of a track, where the song itself is over but the master tape hiss is still audible. I don't remaster an entire track. A lot of CDs are just plain lazy in cleaning this up in the mastering process and I find it very annoying that a great song has to end with hiss that sounds like it's from a casette tape copied three times from the original.

with 3): You obviously strive to boost the volume as much as possible (without clipping), however, the perceived loudness doesn't depend on the peak volume (compare dynamically compressed music with classical music). While peak normalizing usually adds some 3 dB noise, the loudness gain is maybe <1 dB with today's music productions. And don't forget that the music has already been peak-normalized in the studio.

Yes, I understand the difference between peak and average. I've found that -2db for peak is a number that lets me produce MP3s that don't clip. I should be clear that I'm reducing the amplitude when I do this, not raising it. I haven't had a track yet where the peak is more than -2db, and when I do get one, I'll leave it alone, since it don't expect that it would clip on encoding. The music that's been peak-normalized in the studio is what's producing clipped MP3's because they're highly compressed tracks with a peak of ~ -.5. I might find this changes the deeper I get into my CDs, but I went back and did an MP3Gain analysis on a bunch of MP3s I'd already encoded and well over half are clipping.

I'll try some more work with WaveGain, but my initial experience with it was less than positive, and this was partially because of how useful MP3Gain is. It's my understanding that CEP works at 32-bit and dithers down to 16 when it writes the file. Are we talking about 2 different types of dithering? And as for balancing the average volume amongst tracks with WaveGain, I didn't see anyway to pick my target without clipping and it gave me an average that was way too low, which I confirmed looking at the stats in AudioGrabber. But that's for another thread, and to be sure I haven't spent a lot of time with the program. MP3Gain makes complete sense, and its analysis tool is extremely helpful.

with 5): Why do you always want to increase volume? Many playback systems start to have problems at -3 dB below FS already. The reference volume in ReplayGain was introduced to have a safe, uniform volume level across the board. You put this ad absurdum. But i'm sure, one day you'll discover the great benefit of ReplayGain...

As I noted above, I'm almost always decreasing the amplitude as compared to the source. On the rare occasion I didn't need to, MP3Gain has shown that the opportunity to increase it exists. In the alternative, I could have gone back to source and re-encoded without the -2db normalization and wound up in the same place, and perhaps that would be a better way to handle it. The only playback systems I'm concerned about are mine, and I prefer to have the source of the music loud enough to not force me to crank up the volume to abnormal levels just to hear it. What I noticed about WaveGain is that it reduced the amplitude of the tracks so much they sounded like they were recorded under a pillow.

I'll be happy to explore ReplayGain further - after all, it's the foundation for MP3Gain, right?, and I'm very impressed with that, although I do find that the default goal of 89db is a bit too low for my liking, on an individual track basis. I understand that when the day comes to burn a 100 MP3 disc, there's going to be some softer (on an average volume basis) tracks and that the louder ones will have to come down because raising the softer ones will result in clipping. And, as has been pointed out, if, down the road, I find my MP3s are too loud, I can run them thru MP3Gain and kick them down a notch or two without any loss of information.


BTW - what does FS stand for? And what playback systems are you aware of that have problems as amplitude approaches 0db? Are you saying as average volume moves past -3db, or peak? I'm assuming it's peak.

I've only seen the math (and it's not in front of me) for a couple days on the relationship between % and db, but I seem to recall that -1db == 81%, and I know from the analysis that AudioGrabber does, most of the tracks I'm working with have an average around this (usually between 65% and 80%). I'm not trying to pin the VU meter in the red, but I guess, at this point, I don't see the problem with the MP3 itself providing "robust" volume so I don't have to crank the speakers up to 11 just to hear the music.

But I'm here to learn, and I appreciate this discussion.