From: axman@acadia.Kodak.COM (Mike Axman)
Subject: Re: Quality, Gill Pratt's msg. / Mike Axman's reply
Organization: Eastman Kodak Co., Rochester, NY
Distribution: alt
Date: Mon, 9 Nov 92 16:49:41 GMT

In article <01GQUTYJRXPU001U2T@INDYVAX.IUPUI.EDU>, PAOLIVER@INDYVAX.BITNET writes:
>  Kodak has codified an inferior, ancient technology for at least the next
>10-20 years. Congratulations.

>  To give credit, it is becoming clearer in retrospect that there are
>many pieces to the Photo CD puzzle; different format types, multimedia
>aspects waiting to be used, security serialization, etc. I'm simply
>maintaining that the technology exists to do better, and Kodak didn't
>do it.
> After all, if even a modest 2-fold improvement in compression
>were used, 200 pictures and not 100 could be put onto a disk (roughly).

Modest?  Modest?  2X is a modest improvement, eh?  All of your points are
well taken, but you don't sound like you have much experience in image 
compression techniques.  Let's just talk about the encoding part, the Huffman
as used in the Photo CD system.  If we took out the Huffman coding and 
inserted Arithmetic coding such as the Q-coder, the improvement in compression
would be probably 15% at best.  15%!  Now, how do we get the rest of the 
85% for your modest 2X number.  Answer, we throw away data; now our image 
quality has been reduced and we're no longer comparing apples with apples.
My experience has been that choosing Arithmetic encoding as opposed to simple
Huffman would mean a lot more computation in the reconstruction, for a fairly
marginal return.  Maybe things have changed in the last few years, but at 
the time the Huffman decision was made (over 2 years ago), the compression 
arena was still much of an unknown.  JPEG details were still being debated, 
and not many people had even heard of Q-coding.  
Kodak made the decision based on a technique which provided good (if not 
state-of-the-art) performance, and was currently available.

>This means disk sales are cut in half. No, usage of antique compression
>methods was probably deliberate.

If you really believe this you're hopelessly paranoid :-)
It would make a lot more sense to me to just support 1 roll of film per disk.
Then Kodak wouldn't have had to push the multi-session standard, and could
sell about 3X the amount of disks.

Do you think Sony and Philips decided NOT to use DPCM encoding on Audio CDs 
for the same reasons?  You've got to admit, simple PCM is pretty 
"old technology".  In fact, CDs are kind of an old technology on the face.
CD-ROM drives are slow, etc....
High tech does not always mean "better tech" for a given application.
Anyone who's ever worked in product development can verify this.  We wanted 
to make this technology available in the consumer arena.  People 
who over-design products using only the "latest" technology, usually only 
sell these products to governments with big pockets.

Drop the conspiracy theories and I'll take your posts more seriously.  Maybe.

-- 
Mike Axman  
CD-Imaging Advanced Development
Eastman Kodak Company
axman@kodak.com


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