Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!sun-barr!newstop!sun!vector.Eng.Sun.COM!poynton From: poynton@vector.Eng.Sun.COM (Charles A. Poynton) Newsgroups: comp.graphics Subject: Re: Assumed pixel aspect ratio in GIF images? Summary: Sun pixels have been, are and always will be SQUARE! Message-ID: <139559@sun.Eng.Sun.COM> Date: 25 Jul 90 19:00:08 GMT References: <9866@pt.cs.cmu.edu> <10927@chaph.usc.edu> Sender: news@sun.Eng.Sun.COM Reply-To: poynton@sun.com (Ambassador for Square Pixels) Organization: Sun Microsystems, Mountain View Lines: 32 A college student writes in <10927@chaph.usc.edu>: > [Can I] assume that all SunRasters have square pixels? As long as I am alive and working at Sun, all Sun displays will have unity sample aspect ratio, a.k.a. square pixels. > Can someone please mail me the aspect ratio of a Sun display? By knowing that the pixels are guaranteed square, the display pixel counts determine the picture aspect ratio: 1152x900 gives a 1.28:1 picture. Current CRTs have a viewable area of 4:3 aspect ratio so an 1152x900 (1.28:1) or 1280x1024 (1.25:1) display does not quite fill the available width: these formats have wider left and right margins than top and bottom. There is currently a raging debate about "sample aspect ratio" in the HDTV standards community. HDTV is agreed to have a 16:9 picture aspect ratio (about 1.78:1). My proposal for digital representation is 1920x1080, just slightly under 2 Mpx, square pixels of course. Many "proponents" of advanced television production and transmission systems have system parameters inherited from NTSC and many have non-square pixels. C. ----- Charles A. Poynton Sun Microsystems Inc. vox 415-336-7846 2550 Garcia Avenue, MTV21-10 fax 415-969-9131 Mountain View, CA 94043 U.S.A. -----