Mp3Gain Question ... or kicking that dead horse again

Posted by: TankheaD

Mp3Gain Question ... or kicking that dead horse again - 18/06/2006 19:24

Since I was not seeing any volume level changes in my mp2gain modified tunes, I did a bit of searching on the board and came up with these old threads here
and here from 2004. Any new ideas to try here?

I've over 13K tracks on my unit now, all mp3gain adjusted, but none seem to play with change to level. I have played these previously on a (cover your ears!) a Neo Car unit running rockbox-like firmware, and the gain adjustment works as expected.

Now that I've finally gotten my empeg fitted with a large enough drive and installed, and I can get rid of that "other" unit, I find myself fiddling with the volume on just about every other track.

Is there any way to normalize tracks, without resorting to the dynamic volume control?
Posted by: tfabris

Re: Mp3Gain Question ... or kicking that dead horse again - 19/06/2006 01:51

Quote:
Is there any way to normalize tracks, without resorting to the dynamic volume control?

There are some third-party programs that will adjust the volume of the MP3 files and will re-save the files with the volume permanently altered. This is directly writing a volume offset to every frame of every MP3 file, rather than adding a tag that the playback software is expected to interpret.

I don't remember what these programs are called, but you could google for them.

I don't recommend doing that, though. I think someone else on the BBS reported unsatisfactory results when trying it. My memory is fuzzy on that part, though.
Posted by: Bernz

Re: Mp3Gain Question ... or kicking that dead horse again - 21/06/2006 10:28

I'm not really that clueful about the actual encoding for MP3s, but wouldn't changing the amplitude only in some places result in changes to the frequency patterns that are used to compress the sound? In other words, such a program would have to decode, adjust, and re-encode, thereby introducing further artefacts? If that's so, I'd recommend against such a technique (stick with realtime post-decompression level compensation).
Posted by: TankheaD

Re: Mp3Gain Question ... or kicking that dead horse again - 21/06/2006 13:09

Mp3Gain adds/uses the Relative Volume Adjustment frame in the mp3 file (supposedly), which is a native id3v2 frame, to kind of normalize the tracks to a similar level so that you shouldn't have to readjust the player volume control for every track. It's not supposed to alter the actual audio data.

There is a difference in the Relative Vol Adjust frame between id3v2.3 (XRVA or RVAD) and id3v2.4 (RVA2), I think the later allows for more control of how and where the volume is adjusted I think, but I don't know if the empeg recognizes or uses that frame data at all, or which version.

I'm also trying to find out which version of that frame Mp3Gain uses as I haven't seen that specifically spelled out anywhere from their stuff.
Posted by: tfabris

Re: Mp3Gain Question ... or kicking that dead horse again - 21/06/2006 15:18

Quote:
In other words, such a program would have to decode, adjust, and re-encode, thereby introducing further artefacts?

Each frame in an MP3 file has a volume value. The programs I'm thinking of will write a global offset directly to that value without decoding and re-encoding.

I don't think it works very well, it's got its own set of problems. But it's the only other option I know of, which is what the original post asked.
Posted by: Schido

Re: Mp3Gain Question ... or kicking that dead horse again - 10/08/2006 11:08

Was that horse really dead yet? I will try to wake it up.

Since years i normalize every mp3 to 92dB with mp3gain (using the track gain button) before i allow it in my collection. (And yes i did own a neo35 too)

I started doubting if it actually works for the empeg after reading those threads, but now i'm sure it does.
Most of the time i play all songs on my empeg at the random setting, and rarely adjust the volume between songs (except when i really like a song)
After i added the mp3's of the sxsw2006 torrent without doing the normalize thing to them, i can tell one of those songs is playing without looking at the titles, most of them are just so @#$%^&* Loud!

So yes, definetly works for me. Don't notice any clipping either (but that could be just my less then perfect hearing)