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Re: Apple Computer changes its name



Jeff Blakeney wrote:
  To: bieling
On Mon, 15 Jan 2007 05:39:10 -0800, "bieling" <bieling@terra.es>
wrote:


Let's say that we've got a music file with a bitrate x. We burn this
file into a CD (AIFF), then we encode it from the CD's AIFF into
another mp3 file with the same bitrate x as the original. The question
is, have we really lost any quality in the process? I ask because I'm
not so sure... ?


Look at it this way, you start off with the original full quality,
uncompressed data on a CD.  That is compressed into whatever format
(AAC in the case of iTunes) which throws away some of the data (almost
all popular audio compression technologies are lossy) so you get a
lesser quality but smaller version of the data.

If you uncompress that you still don't get the full quality original
back but a version that is good enough.  Now, if you compress that
again, this recompression, which is again lossy, will throw away more
data so you end up with a lesser quality version of the already lesser
quality version.

The only way to avoid this is the only get uncompressed data or data
that has been compressed with a lossless algorithm.  However, I
believe if you get data with higher bit rates you can lessen this
effect.

..or to use a codec that does not suffer additional losses when it
is reapplied to matierial that it has already encoded once.  Of course,
this would not allow moving from AIFF to MP3, but it might get you to
unprotected AIFF--*if* AIFF is information-preserving after the first
encoding.

-michael

NadaNet networking for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

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