Re: Apple Computer changes its name

[bieling@terra.es]

mdj ha escrito:

> Matthew T. Russotto wrote:
>
> > If you use exactly the same codec with exactly the same settings, I'd
> > hope there would be no quality loss.  I don't know if this is the
> > right term, but I call this a "stable" codec -- one where C(D(x)) = x
>
> Even if that's true (which I doubt)- it's impossible to test, as
> there's no way to know what settings Apple used when encoding the
> tracks that are available on iTunes anyway.

Yes there's a way : get info for the file.
It will usually be AAC,128kbps, equivalent to MP3,192kbps.

"AAC achieves better quality sound than MP3 for the same compression
level or smaller file sizes for the same quality audio. For example: A
192 kbps song compressed by MP3 will be the same quality as a 128 kbps
AAC file, which will be smaller in overall size"

"In contrast to MP3's hybrid filter bank, AAC uses the modified
discrete cosine transform (MDCT) together with the increased window
lengths of 1024 points. AAC is much more capable of encoding audio with
streams of complex pulses and square waves than MP3 or MP2."

"In contrast with the MP3 format, which requires royalty payments on
distributed content, no licenses or payments are required to be able to
stream or distribute content in AAC format"

"contrary to popular belief, AAC is not a proprietary format".

> Besides, going from iTunes to some other mp3 player guarantees you'll
> be using different codecs.
> Matt

...if the target player doesn't understand AAC.

Are you really able to tell the difference between a file and it's
(properly) transcoded-just-once copy ? Our ears are not oscilloscopes.
If you can tell with ease, it would really say nothing good of audio
encoding schemes. And even if you (hardly) could, hopefully it won't
necesarily mean that the copy is badly distorted, it just "sounds" a
bit different ? no problem then, when you switch eq. settings, play on
different speakers, or in another room, or switch earphones the music
"sounds" different too. Even your own ears don't hear the same
everytime. Are we talking about such a ridiculous small difference ?
Don't worry very much then.

Jorge.