OK, so here goes another question.

What should I do if I have an audio CD burnt from mp3 files?
(e.g. some free tunes that were streamed/downloaded from the 'net and burnt on a CD by someone else, and I don't own the original mp3 files)?

Is it possible to convert these tracks to an mp3 with no further quality loss?
E.g. if the downloaded tunes were 128 kbps mp3 files, can I convert them back to 128 kbps mp3 and be sure that I didn't lose anything?

If it's possible, how? If it isn't, why?

Many thanks.

AFAIK, it's not possible.


It's not possible because on the CD it's basically in raw WAV/PCM/whatever format. When you encode it to MP3 again you're telling the encoder to compress it and lose parts it deems unnecessary. Since this input WAV file is different than the original input cd source the encoder will make different choices...which means you'll be stuck with the original quality loss and then some more.

There is no way for the encoder to take into account what bits in the WAV represent already lossy compressed bits so it won't lose them even further.

Someone else can probably answer more clearly....

It's currently not possible with available tools, but Fhg is/was doing research on this:
http://www.hydrogenaudio.org/forums/index....reconstruct+mp3