[jamesgangnc]

"Legaldeejay" wrote in message
...
I've always wanted to know whether there is any true quality loss in the
following circumstances:

1. I burn a 192 kbps mp3 file to CD as a .wav file so that it can play
on
a CD player. If I re-create an mp3 file at 192 kbps from that same CD, is
there any quality loss?

2. I open a 192 kbps mp3 file in Soundforge to edit. Soundforge creates
a
temporary file for editing. Once I edit the file, I save the new file as
a
a 192 kbps mp3 file. Is there any quality loss in this process?

3. I run a 192 kbps mp3 file through a normalizing program like Mptrim.
If
the program makes changes to the file, such as eliminating silence at the
beginning of the file and normalizing the volume, is there any quality
loss?

4. When zipping and unzipping mp3 files in Winzip and WinRar, is there
any quality loss?

Thanks


Mp3 is a lossy compression. Basically it will decide to discard portions of
the data that the algorithm believes are insignificant. Adjusting the
compression will preserve more but at a higher cost in space used. On a
computer space is not really an issue so you are better off performing edits
on the uncompressed version of the music straight from the cd. And then
compressing it at the end.

Zipping is a lossless compresison. That means every bit in the original
data is restored when it is uncompressed. You can zip and unzip a thousand
times and still have an exact copy of the original. The are also lossless
compressions specific to music as well. Typically the resulting file from
lossless will only be a bit smaller than the original when music is
compressed. Where as a lossy compression can produce a file that is only a
fraction of the original size.