Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!masscomp!mark From: mark@masscomp.westford.ccur.com (Mark Thompson) Newsgroups: comp.sys.amiga.graphics Subject: Re: DCTV Message-ID: <61928@masscomp.westford.ccur.com> Date: 23 Apr 91 15:51:30 GMT References: <992@celia.UUCP> Organization: Concurrent Computer Corp. Westford MA. Lines: 28 In article , bobl@graphics.rent.com (Bob Lindabury - SysAdm) writes: > that the current DCTV was just a cheap consumer version. They plan a > complete rack-mountable professional unit that will address all the > concerns we are having now with the product (ie: lack of RGB, > resolution, etc.). Also they are suppose to be coming out with a > true 4:2:2 or 4:4:2 system. Can someone tell us all what these > numbers mean? I know they have something to do with chroma and > luminance channels but I am unsure as to the "official" meaning of > these figures. These refer to the sampling rates in a digital component video system. The numbers are actually ratios. 4:2:2 is the sample ratio for Y, Cb, Cr respectively and is the ratio used in all D1 systems. The luminance (Y) is sampled twice as much as the chrominance components because of the eye's decreased sensitivity to color bandwidth. 4:4:4:4 is the digital sampling ratio used in many professional video graphics systems. It also refers to the sample rate on Y, Cb, and Cr and the extra 4 refers to the sampling of a key signal (like an alpha plane for compositing/transparency). If I remember correctly, Digital Creations has plans for a 4:4:4:4 version of DCTV. %~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~% % ` ' Mark Thompson CONCURRENT COMPUTER % % --==* RADIANT *==-- mark@westford.ccur.com Principal Graphics % % ' Image ` ...!uunet!masscomp!mark Hardware Architect % % Productions (508)392-2480 (603)424-1829 & General Nuisance % % % ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~