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From: mxmora@unix.SRI.COM (Matt Mora)
Newsgroups: comp.sys.mac.hardware,comp.sys.mac,rec.video
Subject: Re: MacII and video editors and compressors, is 48 to 1 possible?
Keywords: video compression macII
Message-ID: <10459@unix.SRI.COM>
Date: 27 Mar 90 01:20:00 GMT
References: <39830@apple.Apple.COM>
Reply-To: mxmora@unix.UUCP (Matt Mora)
Followup-To: comp.sys.mac.hardware
Organization: SRI International, Menlo Park, CA
Lines: 34

In article <39830@apple.Apple.COM> jrg@Apple.COM (John R. Galloway Jr.) writes:
>
>	Recently I saw on some PBS computer show (The Computer Cronicles I
>think) an issue on desktop video.  They had a piece on a very high end
>MacII based video editor (about $80K) though no mention of what extra hw
>it was using (and I do not remember the manufacturer).  You read in your
>tape (looked like std VHS) did all the editing from disk, then made a new
>tape.  The claim was that it took 600MB of disk to store 20 mins of video.
>At 30 512 by 512 by 24 (full) frames per second thats only 16KB per (full)
>frame or a compression ratio of about 48 to 1.  Just for the editing process
>you could drop every other line, and then known 20-25 to 1 compression parts
>would make it, but to produce the final tape you would want full info, which
>also would have to come from disk I would think.  Is 48 to 1 possible? 

I seen the same show but only the last part about the IBM microchanel.

A company called C-Cube as a chip that can do up to 200 to 1 compression.
Its based on the JPEG standard. The chip is called CL550. Compression 
time is less than two seconds but mostly will be less than .25 sec.

The current issue of macweek has an article about the chip.
(MacWEEK 27 March 1990) vol 4 no. 12







-- 
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Matthew Mora
SRI International                       mxmora@unix.sri.com
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