Re: AAC V MP3

["mark_harrison_uk2" <mph@xxxxxxxxxxxxxxx>]

--- In ukha_d@xxxxxxx, Mark Hallows <markhallows@p...> wrote:
> erm question... What is lossless ? Do you mean a straight rip ?

Lossless compression uses an algorithm like "ZIP". The point of
lossless is that you CAN restore every single bit of information to
regain an entire duplicate of the original non-compressed format.

The reason that this WASN'T done all along is that you need a fairly
meaty processor to do it in real-time, and fairly meaty processors
mean higher power requirements and more heat dissipation - neither of
which are exactly ideal characteristics for mobile devices. (To be
fair, 5 years of miniturisation on, it wouldn't be too big a problem.)

The most common lossless compression algorithm for audio is FLAC. (Zip
requires an awful lot of RAM as "working space" to decode the
file,
and was never intended for decoding BITS of a file on the fly - FLAC
was engineered for "decode as you go")

WAV is the completely vanilla - "exact reproduction of every
bit",
which is why the files are so huge.

The lossy compression modes throw away some of the information, but
are all designed by audio engineers to try to only throw away stuff
that isn't normally audible... and the engineering characteristics of
mobile players and headphones certainly impse a sufficiently high
noise floor that this has proved succesful.

For networked players, the sound quality, even of the best MP3 is
slightly down from a good CD player...

... but the convenience of being able to dial a track beats the
marginal difference, even for a self-confessed audiophile like myself.

Regards,

Mark