Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!rutgers!cbmvax!peter From: peter@cbmvax.commodore.com (Peter Cherna) Newsgroups: comp.sys.amiga Subject: Re: Black Belt Video Message-ID: <9292@cbmvax.commodore.com> Date: 11 Jan 90 14:50:42 GMT References: <1182@m3.mfci.UUCP> <5357@tekig5.PEN.TEK.COM> Reply-To: peter@cbmvax.commodore.com (Peter Cherna) Distribution: comp Organization: Commodore, West Chester, PA Lines: 55 In article <5357@tekig5.PEN.TEK.COM> waynekn@tekig5.PEN.TEK.COM (Wayne Knapp) writes: >> I'm posting these for Ben Williams of Black Belt systems. He does not >> usenet access. > >> To Wayne Knapp: >> ... >> We utilize 16 pixels as the cookie, which leaves quite a bit >> of data bandwidth (per line) left over. >> ... >Yes I realise my error and that you only use 8 lines vs. the 24 >lines I though (in the interlace mode). I already acknowledge my >error your posting is late. > (misc observations deleted) ... >However I will take a pot shot at you now. In the posting about how >the Black Belt video works (a really nice posting by the way) there >is detail about the 8 bit HAM mode. The posting states that over >260,000 colors are possible on screen. Well isn't that a bit hard >with less than 40,000 pixels. (Should say something like > 30,000 ^^^^^^ >colors out of 260,000 possible). Maybe we should all watch our math >a little closer. Brap. Strike two in the mathematics World Series. :-) Non-overscan, you can get 320x400 pixels with the BB product, which is more like 128,000 pixels. Did someone say overscan? Ok, how about 362 by 482 overscan, less 8 lines for the register data (4 per field). That's over 173,000 pixels. It turns out that in a screwy way there may be more than 260,000 possible colors. In HAM, each pixel can be a color register, or a modification of the previous pixel. If it's a modification, they get to change 6 bits of r, g, or b. But they may allow all 8 bits-per-gun (24) to be set from a color register. You'd be able to modify the top 6 only, but you could judiciuously set the bottom two from time to time. If that were so, and you allowed me to choose 64 of the color register values, I could get to _any_ color value in 24-bit space within four pixels. So their marketing types could go wild and say 24-bit color in HAM! But it would really be 18-bit with very awkward (basically incidental) control over the bottom two bits-per-gun. > Wayne Knapp Peter -- Peter Cherna, Software Engineer, Commodore-Amiga, Inc. {uunet|rutgers}!cbmvax!peter peter@cbmvax.cbm.commodore.com My opinions do not necessarily represent the opinions of my employer.