Sonic Degradation in MP3 Conversion

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dmcsilva

New member
As S2k stated avoid BladeEnc like the plague. Also, Scmpx does give good results. To decrease the detectable (by humans) quality difference between .wav and .mp3, encode at at least 192k-or even higher-depending on your encoder, and the dynamics of the audio which you are encoding.

dmc
 
Kind of a technical question. If I have converted a .wav to .mp3 format and then back again what kind of sonic degradation occurs? Similarly, if one "zips" a .wav and then unzips it, what kind of degradation occurs? As a follow up...is there any kind of process (i.e. eq, harmonic exciters) which will help to restore or replicate that which may have been lost? Thanx all. I love this place.
 
Unfortunately, MP3 is a "lossy" compression scheme. That is, you cannot retrieve the original version from the compressed version. What you have is an "approximation" of the original. The JPEG image format is similarly lossy. Sometimes when it comes to graphics and music, it is ok to sacrifice some quality in the name of file size....especially when transfering files over a network (one of the primary reasons compression was created).

One the other hand, any sort of data compression must NOT be lossy. You can't run an "approximation" of a program :) So schemes like ZIP are not lossy. When you extract the files from a ZIP archive, you end up with exact copies of the original files.

What's this mean to music? Even if you convert an MP3 back to wave, you're going to end up with a wave that sounds EXACTLY like the MP3, not the wave the the MP3 was created from. Now, if you zip up a wave file and then extract it later, you do end up with a perfect copy. The catch? Waves do not lend themselves to being zipped very well.

I would say that there is no way to make a wave created from an MP3 sound better...it would be difficult and the end result would sound very different than the original product. A better solution would be to look into techniques for creating a better sounding MP3 in the first place. If you listen closely to an MP3, its weaknesses will pop out at you, and it may be possible to compensate for some of them.

The best place to start though, is with a good MP3 encoder/decoder. I fully recommend SCMPX and DO NOT recommend BladeEnc (both are free). You'd be suprised at the difference an encoder makes.

Slackmaster 2000
 
I appreciate the replies. A while back I went through all sorts of computer woes with the upshot being that -despite my attempts- to back-up my work, there is one piece which may only be found in .mp3 form. That's why I was wondering if there was anything that can be done that would even approach sonically rectifying what may have been lost. I probably encoded from either Cakewalk or Wavelab.
 
Slack covered it pretty well. You might be able to doctor some of the artifacts and noise by converting to wav and experimenting with an EQ plug-in. But for the most part, you're stuck with the quality you hear on the source. It won't get a whole lot better than that.
 
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