Xref: utzoo rec.video:13795 comp.misc:9701
Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!pacbell.com!decwrl!ucbvax!iwarp.intel.com!news
From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: rec.video,comp.misc
Subject: Re: Video and computer memory
Message-ID: <1990Aug1.020447.14789@iwarp.intel.com>
Date: 1 Aug 90 02:04:47 GMT
References: <29@meme.stanford.edu> <1990Jul31.204803.25358@eng.umd.edu>
Sender: news@iwarp.intel.com
Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Followup-To: rec.video
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 31
In-Reply-To: naiming@eng.umd.edu (Naiming Shen)

In article <1990Jul31.204803.25358@eng.umd.edu>, naiming@eng (Naiming Shen) writes:
| You even have trouble to put one second of video into memory.
| the X is about 300-600 and Y is 525. Assume you digitize it with
| 8 bits per pixel. 
| You have:
|   400*525 X 30 = 6.3 M Bytes per second.

OK, here goes my ignorance, but isn't video transmitted on a 3.58MHz
carrier (or whatever you call it... I'm not an analog guy).  If so, I
had always presumed that you couldn't stuff more than 2 or 3 Mbits/sec
(theoretical) down that size of pipe.  That'd put your estimate off by
a factor of 20.  Am *I* really that far off?  Also, I've never seen an
NTSC with Red in one "pixel" and yellow (blue+green, right?) in the
next "pixel" that didn't get sorta smeared together, so I suspect you
really have only two or three new bits of information per pixel.

Am I close?

OK, lets look at it another way.  8mm Exabyte tape, two hour style,
holds 2.2 GBytes.  That'd put it at 0.3 megabytes/sec, or 2.5
megabits/sec.  Pretty close to my numbers.  I'm not saying anything
about the efficiency of the Exabyte 8mm drive, but it's gotta be
close.  If there were a way to stuff 6.3MByte/sec into those tapes,
don't you think they would have tried?

Just a shot in the dark,
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/