* Eric Woudenberg <[EMAIL PROTECTED]> on Sat, 11 Mar 2000
| I'm missing something. Didn't I demonstrate that MP3 (a more complex
| coder than ATRAC)
Whosoever has told you that is full of crap. At the fundamental level, MP3
(MPEG-1 Layer III audio) has a pathetic time-frequency distribution model.
At lower bitrates, 128Kbps (allegedly "near-CD quality) and below, audio
signals with lots of high and low frequency sounds but relatively little in
the middle get... "cropped" is the best way I can describe it. When the
time-frequency block is full, any remaining signal gets thrown away,
whether or not it is significant. I understand that Prince's "Raspberry
Beret" is an "MP3 breaker" for this reason, but I have never made the
comparison personally.
ATRAC has a much more sophisticated time-frequency distribution model, one
that uses the same psychoaccoustic model as the bit reduction algorithm.
The result is that time-frequency blocks are allocated based on "density".
Frequency ranges with more sound get more bandwidth; those with less sound
get proportionally less bandwidth.
| runs at 3X realtime on my 500MHZ desktop machine? Do you still somehow
| think ATRAC would be slower than realtime on such a machine?
For sound quality as close to ATRAC 4 as MP3 is capable of achieving, yes.
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