Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!lll-winken!taco!hobbes!kdarling From: kdarling@hobbes.ncsu.edu (Kevin Darling) Newsgroups: comp.sys.amiga.graphics Subject: Re: Colorburst and Animation Message-ID: <1991Mar14.231042.26446@ncsu.edu> Date: 14 Mar 91 23:10:42 GMT References: <13948@life.ai.mit.edu> Sender: news@ncsu.edu (USENET News System) Organization: North Carolina State University Lines: 45 In <13948@life.ai.mit.edu> rjc@geech.ai.mit.edu (Ray Cromwell) writes: > kdarling@hobbes.ncsu.edu (Kevin Darling) writes: >>Now sure, you can fill up the CHIP ram with a limited amount of preset data, >>use lower bits/pixel, slow down fps, and so on. You can bet that demos do >>just that. But any way you cut it, their 5.5MB/s figure is akin to those >>common hard disk xfr specs which ignore seeks, etc.... it's a best-case, >>limited duration transfer rate... dependent upon source data availability. >> > Your example provides a worst case scenario, I am going to provide the > best case. Clever tricks are always availible to help: > [ clever trick follows :-] You're absolutely right; in fact my friend and I had also immediately thought of turning off vid DMA during reload (actually, I think you'd only need to go to a lower res). So as we've both now mentioned (and most people would've inferred), there are several techniques they could use to aid in transferring the data... no argument there. > So it takes a total of 1/30th + 1/15th second to insure colorburst > gets a frame constantly. This amounts to 20fps which is acceptable. Ooops :-). That totals 3/30th second, which is _10fps_ at 320x200x24. Or roughly 5fps at 320x400x24, 20+fps at 320x200x12, and so on. Which was my main point. The resulting steady rate of 1.9 megabytes/sec for the given example is not quite what was originally proposed: >>> The Colorburst transfers data at 5.5 megabytes/sec through the db23 port. >>> A lo-res screen is 40bytes widex200 lines deep x 24 bits. That's 192k, >>> at 5.5mb/sec gives up 30 frames per second. That was, as I replied, a short duration best-case scenario for fullscreen, fullmotion. In addition, you would lose the use of your Amiga screens while all that was going on, which might be a factor for some users. > Colorburst is a great deal, even if it couldn't animate, which it can. It's definitely priced extremely well for what you get; there never was any debate from me on that subject :-). And knowing that animations are rarely full-screen, and can be dropped in plane count, I've never had any doubt that nice animation was possible on it. My friend and I just always cringe when we see top specs stated with no limitations or caveats. More info was needed to see the whole picture. I think you and I have covered things now . best regards - kev