From: wb <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, March 12, 2000 11:40 PM
Subject: MD: ATRAC Type-WB
> I don't wanna interfere into the discussion whether or not ATRAC encoding
is
> possible on todays PCs (please no flames!!), but.... I have an ATRAC
> encoder/decoder running on my PentiumII-450Mhz (with good old Win95b). I
named my
> encoder/decoder ATRAC Type-WB (guess why!) Version 3.5-0.91 (this means
the
> psycho-acoustic model has been read out from a MD-Deck with ATRAC-Version
3.5 --
> MDS-JA3ES).
Source code available? .......how the **** did you get the model out of the
MD? Did you use a hardware ripper or something?
> The encoder eats about 75-80% of the CPU time and the decoder needs
20-25%. Both
> encoder and decoder are written in a high-lever language and have yet not
been
> opimized (no MMX and so on).
Would be interested to find out *which* high level language. If it's VB then
the CPU usage if it were written in low-level such as assembler would
probably go down to about 10%!! If you've used C++ then I would expect that
to drop to 40% or 50%. With MMX enhancement I think it would be reasonable
to assume 2x encoding on a 450MHz system possible.
> The encoder even writes the bitstream in the exact
> way a MD recorder would do, which means, if you write the encoded file
onto a
> MiniDisc, set the pointers in the UTOC correcly and put the disc into a MD
player
> it will play.
Does this mean you are also simulating the method of writing to MD or just
using the same file format?
> About 15% of the CPU time is used for the QMF and the type
> conversion (float2integer) -- unbelievable; 10% is needed for the bit
> packing/unpacking and the fast cosine transforms. A lot of improvement
could be
> done here since I use the FCT algorithm for the DCT type I, but ATRAC uses
DCT
> type IV. Anyway. My encoder version (0.91) has still some problems with
the
> BlockSize decision.
Interesting, would love to see the source for this one!!
> Since sony has registered the name "ATRAC", I am already thinking about a
new
> name for my encoder/decoder. How about "CARTA" (pronounced "ATRAC" -- if
you read
> it from right to left! :) Any suggestion are welcome! BTW: Everybody with
some
> math knowlege can build their own en/decoder. All the information you need
is
> availble on the net (no kidding!)
>
> wolfgang
CARTA is a cool name, but it sounds a little like ENCARTA - as in the
encyclopoedia.....
> ps: I now know why Sony announce their new gear (MDS-JB940) so early.
Well, I
> somehow have to prepare my parents about what my wishes for next chistmas
are!
> Although, if I remember correctly, my Mom told me if I ever come home with
new MD
> stuff, I will be kicked out of the house (that I wouldn't really care...
well
> yes, I would) and she will throw away all my MD stuff (that I surely WOULD
> care!!)
Ok, parent trick. Get the new MD and take it to a friends house. Check in
his/her loft - they probably have a box for a CD player. Use that to take
the MD home and set it up. You then hide your existing MD round your friends
house and sell it. Unless they check model numbers they probably wont notice
anything different. :o)
Magic
--
"Creativity is more a birthright than an acquisition, and the power of sound
is wisdom and understanding applied to the power of vibration."
Location : Portsmouth, England, UK
Homepage : http://www.mattnet.freeserve.co.uk
EMail : [EMAIL PROTECTED]
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