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View Full Version : Normalization : can this do the impossible?



Black Tiger
18th January 2009, 09:34 AM
I've just been tipped of about this program:
http://mp3gain.sourceforge.net/download.php

I have been after something like this for ages because it claims to normalize all of your MP3 files without first decoding them, adjusting the volume, then recode them back to MP3 which all the other programs seem to do (which compresses and degrades the quality even more ) this one doesn't?!

I am still a little skeptical of this program, is there anyone here who has tried it and it actually works? I can't see how it can without preforming the actions I mentioned above. But it says it doesn't?!
Being a musician, I'm a little fussy when it comes to sound, I would hate to run this program over all my MP3s, only to have them degraded and undo all the work I did ripping them into high quality.

Brad
18th January 2009, 09:40 AM
We've all been using this for years. Does the trick no problem without any sort of decoding.

Brad

David_AVD
18th January 2009, 10:42 AM
... mp3gain ...

I am still a little skeptical of this program, is there anyone here who has tried it and it actually works? I can't see how it can without preforming the actions I mentioned above. But it says it doesn't?!

I've wondered the same thing. Maybe it doesn't alter the content as such but modifies a "level" tag in there to instruct the decoding / playing process to apply gain / reduction? I have no idea if mp3 streams even support this.

rod71
18th January 2009, 11:12 AM
Yeah, the program will analyse the file (which takes the most time in the process) and then adjust the gain either up or down. Default is 89db, but you can overide that.

David_AVD
18th January 2009, 01:35 PM
Yes, but how does it adjust the volume?

Maybe there's a simple way to alter the level of an mp3 stream without decoding and re-encoding. I don't know enough about the intricate workings of an mp3 stream to know.

My thought was that there might be a way to tell the decoder what base level to use. If that were true, mp3gain could be analysing the overall stream and changing that value.


EDIT: from the mp3gain pages:


the changes MP3Gain makes are completely lossless. There is no quality lost in the change because the program adjusts the mp3 file directly, without decoding and re-encoding.


I still don't know exactly how it does it though.

EDIT AGAIN:


The Problem

Not all CDs sound equally loud. The perceived loudness of mp3s is even more variable. Whilst different musical moods require that some tracks should sound louder than others, the loudness of a given CD has more to do with the year of issue or the whim of the producer than the intended emotional effect. If we add to this chaos the inconsistent quality of mp3 encoding, it's no wonder that a random play through your music collection can have you leaping for the volume control every other track.

The solution

There is a remarkably simple solution to this annoyance, and that is to store the required replay gain for each track within the track. This concept is called "MetaData" – data about data. It's already possible to store the title, artist, and CD track number within an mp3 file using the ID3 standard. The later ID3v2 standard also incorporates the ability to store a track relative volume adjustment, which can be used to "fix" quiet or loud sounding mp3s.

nellistc
18th January 2009, 02:12 PM
Yes, but how does it adjust the volume?


It does it in one of two ways:

1- It writes the adjustment in the tag. For this to work, you need to play it back with a replaygain compatible player. The player will read the data from the tag and adjust the volume.

2- It modifies the file, but writes undo information in a tag. If you do it this way, you don't need a replaygain compatible player. You can run the files through mp3gain again to remove the adjustment and delete the undo info.

Both methods are lossless.


cheers.

Nidzdotnet
19th January 2009, 10:39 AM
I MP3gain'ed all my entire music collection on my ipod and I hated it.. I found that it would just raise and lower the volume level on the fly so music would go soft then loud again as the program would try to level out the volume levels.. I find it not to work properly.. Not the same as manually loading up a mp3 and adjusting the volume level of the whole track and then saving it as a certain DB output. I've tried a few Normalizers and find than none do a good job.

Brad
19th January 2009, 11:47 AM
I MP3gain'ed all my entire music collection on my ipod and I hated it.. I found that it would just raise and lower the volume level on the fly so music would go soft then loud again as the program would try to level out the volume levels.. I find it not to work properly.. Not the same as manually loading up a mp3 and adjusting the volume level of the whole track and then saving it as a certain DB output. I've tried a few Normalizers and find than none do a good job.

With MP3Gain you should use Album mode so that it actually analyses the natural peaks and lows. That way it doesn't screw with the normal album volumes.

Brad

acejas
19th January 2009, 12:42 PM
getting a lot of Error 6 in txtAlbumMonitor_Change (Mp3Gain). Done a google and nothing :(
Similar error for single...so obviously has something to do with my albums

Brad
19th January 2009, 01:01 PM
Damn...never seen that error before. In fact the only errors I've gotten are from partially downloaded files. You think the file is complete when in fact it isn't.

Brad

headkaze
19th January 2009, 01:18 PM
You could run everything through a hardware compressor (http://en.wikipedia.org/wiki/Dynamic_range_compression) like radio stations do. Do a search on eBay for "audio compressor" there are a few on there.

There are also some links to software that does the same thing at the end of the wiki page.

Black Tiger
19th January 2009, 01:21 PM
Thanks for your help everyone ;) I'm so pleased that it doesn't affect the quality, that was my only concern

Knowing that, this is possibly the best app I have stumbled on in ages!!! :cool: