Path: utzoo!mnetor!intacc!mann From: mann@intacc.uucp (Jeff Mann) Newsgroups: comp.graphics Subject: Re: Animating images on PC's and Workstations Message-ID: <1991Jun12.073358.12295@intacc.uucp> Date: 12 Jun 91 07:33:58 GMT References: <1991Jun10.185556.10123@news.nd.edu> Organization: Inter/Access Artists' Centre Toronto Lines: 98 In article <1991Jun10.185556.10123@news.nd.edu> jkellow@bach.helios.nd.edu (John Kellow) writes: > > >I just read the press release on Apple's new system software called >QuickTime for including multimedia in applications. It includes >support for animating images, playing digitized sounds, compressing >images, controlling video equipment, and playing digitized video >from a hard disk. It sounded very promising so I was wondering, Whats >the current state of the art in animating images on PCs and Workstations? >I'm not talking about special multimedia hardware, just ordinary >PC's, Macs, Sparcstations, Amigas, etc. QuickTime will be able to play low-resolution video clips in small windows on the Mac. It uses software compression/decompression. It won't be useful for video production, but will certainly add some interesting possibilities for any software application, not just multi-media. Imagine pulling down the help function, and instead of a list of instructions, you get a nice little video clip showing you exactly what to do. And you thought voice mail was fun :-) >So where are the bottlenecks for doing TV quality animation on a PC >or Workstation (what is TV quality anyway 640x480x24bit? 16bit?). That's about right - 16bit will give a reasonable TV-like quality, while 24 bits are really needed to provide the full bandwidth of TV. TV has a fixed 525 rows (interlaced), but they are usually not all visible, so 480 is pretty much ok. The horizontal resolution is an analog function. For example, S-VHS and Hi-8 have around 400 lines (columns), while higher end systems can exceed 500. I think broadcast TV is around 300-400 lines. Of course, the higher the original resolution of the graphics, the better the picture will be after the transfer. Most broadcast-quality video cameras these days have around 700 lines of horizontal resolution. >Is the limitation in disk->host memory, host memory->framebuffer memory, Certainly the disk is the major bottleneck not only in terms of speed but of storage space. With 640x480x24bit, that's nearly a megabyte per frame. At 30 frames per second (standard video rate), you're going to need nearly *two gigabytes per minute* ! So your standard 600meg optical disk is going to get you a whopping 20 seconds of video -- IF it could handle the transfer speed, which it can't. Neither can any standard PC memory bus. The solution to all this is video compression, using a scheme like the JPEG or MPEG (which is still under development I believe). Several companies, including NeXT, announced systems which used the much-hyped C-Cube JPEG compression chip which promised incredible results but failed to deliver. So the products never appeared. I don't know what the state of the C-Cube chip is right now. Currently, the only commercially available PC system I know of that can play reasonable quality video from a hard disk is an Amiga, using a fast disk/controller, and a "black box" called DCTV. I believe that DCTV uses a proprietary compression scheme. Frames are stored in a standard lower-resolution Amiga format, except that the first few scan lines contain control information that allow DCTV to expand it to 24-bit (so they claim) quality. I've seen the system, and the quality was quite good in the demo. I haven't had a chance to try it out myself. One problem is that there is no facility to record full-motion video, only to play it back -- digitising takes several seconds per frame with DCTV. Several systems for the Macintosh are due out by the end of this year. Super Mac Technology has announced a product -- I saw a demo of it last year. It was pretty glitchy back then, but it was just a prototype. The final product should be able to record as well as play back, and should come in around $5000.US. The recent MacUser magazine has a very good article about this whole subject. >host processor speed ? It seems that things are moving in the direction >of desktop computers being able handle digital video like they handle >digital sound now, but I can't really see it on the current generation >of machines. I think the possibilities are quite incredible. Certainly there are systems available which can do this (the Quantel Harry for instance) but they are in the six-figure range right now. I guess I first started to realize the kind of things you could do almost ten years ago, and I've been waiting for a product ever since :-) I'm hoping to be able to bust my piggy bank and get one as soon as there's something available. Nope, it doesn't seem to be here quite yet, but give it another year. Unless (hoping) someone knows something I don't... >John Kellow >kellow@ndcvx.cc.nd.edu P.S. -- another really interesting aspect of video compression is that it should be working well when ISDN becomes widely available. With a system capable of both selectively sending and receiving video over phone lines, I think we're going to see some pretty amazing changes in what we now think of as TV -- talk about 'yer multimedia :-) All this could be happening in the next two years. I wonder what it's going to be called? I don't think TV quite covers it... =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- | Jeff Mann Inter/Access Artists' Computer Centre, Toronto [416] 535-8601 | | ...uunet!mnetor!intacc!mann intacc!mann@nexus.yorku.ca mann@intacc.uucp | | The Matrix Artists' Computer Network BBS: [416] 535-7598 2400 8N1 | =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-