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From: jesup@cbmvax.cbm.commodore.com (Randell Jesup)
Newsgroups: comp.arch.storage,comp.graphics
Subject: Re: Products to handle HDTV moving pircture (180MB/sec)
Message-ID: <C76vuz.LsM@cbmvax.cbm.commodore.com>
Date: 17 May 93 21:04:10 GMT
References: <42814@twics.co.jp>
Reply-To: jesup@cbmvax.cbm.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 31

kazsato@twics.co.jp writes:
>I'd like to know if there is any system (CPU + HD array + framebuffer)
>which can play and record HDTV quality moving picture in realtime.
>
>HDTV has about 6MB/frame, so recording/playing moving picture will need
>about 180MB/sec bandwidth. I'm thinking to treat the raw data.. not
>compressed. 

	Actually, for digital HDTV systems that's far higher bandwidth than
you need, unless there's some reason you must work in fully-uncompressed
HDTV.  Also, my calculations is that each frame should be well under 6MB,
even using 24 bits/pixel (which is more bits than you actually need - 15 or
18 should be enough for a moving picture).  1600x1100x16bits is 3.5MB (I'm
guessing at HDTV resolution - it may be a bit wider than 1600, I'm fairly
sure of the 1100 number for most of the digital proposals).

	I hope you have a very fast memory system as well - 180MB/s while
displaying will require a heavily interleaved VRAM system.

	Unless you have a _very_ compelling reason, I'd advise trying to use
at least somewhat compressed data.  You don't have to go to full compression
to get to a level where the data IO requirements are much cheaper and easier
to deal with.

-- 
GNU Emacs is a LISP operating system disguised as a word processor.
 - Doug Mohney, in comp.arch

Randell Jesup, Jack-of-quite-a-few-trades, Commodore Engineering.
jesup@cbmvax.commodore.com or rutgers!cbmvax!jesup	BIX: rjesup  
Disclaimer: Nothing I say is anything other than my personal opinion.
