Path: utzoo!attcan!uunet!jarthur!usc!zaphod.mps.ohio-state.edu!rpi!sci.ccny.cuny.edu!phri!roy From: roy@phri.nyu.edu (Roy Smith) Newsgroups: sci.electronics Subject: Re: I don't need HDTV! Message-ID: <1990Mar16.172343.10577@phri.nyu.edu> Date: 16 Mar 90 17:23:43 GMT References: <8Zx8Ip200ioEMMrHEF@andrew.cmu.edu> <132618@sun.Eng.Sun.COM> <2694@sactoh0.UUCP> <1990Mar13.023805.24765@athena.mit.edu> <1990Mar15.090214.9871@spectre.ccsf.caltech.edu> <7322@celit.fps.co <1990Mar15. Sender: news@phri.nyu.edu (News System) Organization: Public Health Research Institute, New York City Lines: 25 toddpw@tybalt.caltech.edu (Todd P. Whitesel) writes: > square pixels would be nice for computer graphics. I think the thing to realize here is that there is very little in common between broadcast TV and computer graphics. First off, you have to worry about bandwidth. With 1024 x 1024 x 24 bit graphics at 72 Hz, you're talking about 75 million pixels per second. It may be fine to talk about 100 MHz video bandwidth on each of three coax cables in a lab, but how are you going to transmit that over the air? One of the absolute limits of broadcasting is that bandwidth is a finite resouce. Unless you can change the gravitational constant of the universe by "just doing it", you have to live with that fact. Secondly, with interactive computer graphics, the ratio of sources to displays is about 1:1. With broadcast TV, there are many, many more recievers than there are sources of material to watch. Using square pixels may make life easier for the ray tracer folks, but that's just tough on them. Is there any fundemental reason why you can't do ray tracing with rectangular pixels? If using rectangular pixels saves broadcast bandwidth, or makes it easier to build a reciever, it's A Good Thing. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,philabs,cmcl2,rutgers,hombre}!phri!roy "My karma ran over my dogma"