Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!mips!daver!ditka!zorch!amiga0!mykes From: mykes@amiga0.SF-Bay.ORG (Mike Schwartz) Newsgroups: comp.sys.amiga.advocacy Subject: Re: AMIGA Message-ID: Date: 10 May 91 10:01:42 GMT References: <1991May6.115535.8982@sugar.hackercorp.com> <1991May6.164821.8807@cunixf.cc.columbia.edu> <937@cns.SanDiego.NCR.COM> <1991May8.062658.14796@cunixf.cc.columbia.edu> Organization: Amiga makes it possible Lines: 54 In article <1991May8.062658.14796@cunixf.cc.columbia.edu> es1@cunixb.cc.columbia.edu (Ethan Solomita) writes: >In article <937@cns.SanDiego.NCR.COM> dltaylor@cns.SanDiego.NCR.COM (Dan Taylor) writes: >>In <1991May6.164821.8807@cunixf.cc.columbia.edu> es1@cunixb.cc.columbia.edu (Ethan Solomita) writes: >>> I'm afraid your hard drive is a tad faster than mine. My >>>Quantum can read slightly greater than 1MB/sec I believe if it is >>>nice and contiguous, but if each frame is 32K then that makes >>>1920K/sec. However, 60fps is irrelevant. 30 and 24 are far more >>>meaningful. >> >>Most Amiga animations are stored in a format that does NOT require a >>complete copy of EACH frame image, rather, deltas between frames are >>used whenever possible, usually within a "scene". Between the CPU >>and the graphics coprocessors, it is easily possible to update the >>next frame, then use the "copper" to switch at vertical sync. I think >>the real numbers are more like 60 "fields" per second, which is the >>30 frames per second you mentioned. >> > Oh, I have no doubt that a blitter could do 60fps on a >low-res screen, or an 030 on a high-res screen. My question was >simply about getting it into memory. Do compressed ANIMs lend >themselves to off-disk loading? I hadn't thought it would be as >easy: frames aren't fixed size. If it is, how much compression do >you usually get? And how about on digitized images? > >>Our disks can sustain near-megabyte per second throughput, but I haven't >>seen one, myself, that can sustain 2 mbs through the file system. The >>original ZorroII, as in the A2000 family, has a (roughly) 4 mbs data >>rate, so it IS possible to run the 2 mbs of disk data, and handle the >>overhead. >> > Maybe try a Wren drive. I've been told that they'll do >2M/sec, but the question would then be the realistic throughput >of the controller. > >>Dan Taylor > > > -- Ethan > >"Brain! Brain! What is Brain?" ANIM format is quite good because of XOR compression from frame to frame. ANIM format is NOT good if you are using digitized HAM images (due to noise created during the digitizing process). In fact, HAM images, which require 48K for low res and 96K for 320x400 (recommended) don't compress well at all using standard techniques (LZH et al). The most impressive animations I have seen running from hard disk aren't full screen in size (but still are very impressive none the less). -- **************************************************** * I want games that look like Shadow of the Beast * * but play like Leisure Suit Larry. * ****************************************************