Re: Apple Computer changes its name

[pausch@saaf.se (Paul Schlyter)]

In article <3eenq2hg846vmqg9evgk6cigmkn3lto67d@4ax.com>,
Jeff Blakeney <jeff.blakeney@a2central.com.remove-4qv-this> 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.

Otoh, if the two lossy compression algorithms pretty much agree on
what kind of information should be thrown away, perhaps less will be
thrown away during the second lossy compression, because most of what
"should" have been thrown away were thrown away already at the first
lossy compression.
 
> 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.
> 
> Jeff Blakeney
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