Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!rex!rouge!ralph!elgamy!elg From: elg@elgamy.raidernet.com (Eric Lee Green) Newsgroups: comp.multimedia Subject: Re: NeXT/Amiga Multimedia...DROP IT!!! Message-ID: <00677399055@elgamy.raidernet.com> Date: 20 Jun 91 05:24:15 GMT References: <2561@gold.gvg.tek.com> <14318@dog.ee.lbl.gov> <1991Jun15.225740.3566@ux1.cso.uiuc.edu> Organization: Eric's Amiga 2000 @ Home Lines: 115 From article <2561@gold.gvg.tek.com>, by johna@gold.gvg.tek.com (John Abt): > Some of us do not know anything about the Amiga. Could someone > post, in simple terms, devoid of BS, just exactly what it is about > the Amiga that makes it a good multimedia platform? Okay. As a non-rabid-fanatic type, I guess I can do that. Do note that I am posting this message from an Amiga, which means that some of my non-Amiga details may be inaccurate. However, I've seen much of the stuff out there for the Amiga. Okay, first of all: video output. This isn't such a big deal today, since ISA and Mac cards exist to do the same thing, but every Amiga puts out genlock-ready NTSC. The professional-quality genlocks (which are around $300-$600, depending on what you want) have inputs for an external video source and external synch. The Amiga graphics chip set is capable of synching to that external synch. I.e., no additional hardware required beyond the genlock, if you're wanting video. Double-buffering is ridiculously easy with the Amiga. All Amigas come with the capability. In addition, access to the framebuffer is fairly fast if you're careful about what video mode you're using... especially on the Amiga 3000 series, which has a 32-bit path to video RAM (I know of no IBM-type video buffers with such a path, except perhaps some of the Microchannel cards). Amiga hard drive controllers, too, are generally fairly fast, which is important for getting the data into memory in the first place... again, this is especially true of the Amiga 3000 series, which has a 32-bit DMA controller that can easily handle anything up to the limits of SCSI-1 (which is about 4mb/sec... still a bit faster than the fastest SCSI hard drives, which can only do about 2.2mb/sec continuously). When you're trying to display fast animations and have realistic sampled sounds running simultaneously, having that bandwidth becomes critical. Drawbacks: Amiga resolution is not state-of-the-art. It is fine for most titling needs, e.g., if you want to run a cable directory channel off of your Amiga (which is what a large percentage of cable companies are doing now), but if you're wanting to put out spectacular ray-traced images, you need to buy a more expensive display option. The three with which I am familiar are the Ham-E, DCTV, and the Video Toaster. Ham-E and DCTV are simple video enhancers. The Video Toaster is a whole lot more. Talking about the Video Toaster... this $1500 widget has the big blurb "A TV studio in a box!" on it. Which it isn't, but it does have a number of interesting features. It does a bunch of wipes, fades, etc. between a number of video sources, both internal and external sources, it has a built-in genlock of course though all these sources must be time-base-corrected, and it has its own video frame buffer which has much better color availability than the standard Amiga display. (Note that since we're talking NTSC here, color availability, rather than absolute horizontal resolution, is more what's needed, to allow smoother transitions with less fringing etc.) It can capture frames from an external source and then you can use the video image manipulation tools that come with it to do all sorts of things such as, say, draw a mustache on a politician's face :-), or wrap the image around a ray-traced ball. (A ray tracer and a paint package comes with the Toaster). The Toaster has a couple of problems, though... it's not QUITE the best thing since sliced bread. It doesn't run on the latest Amiga 3000 computers, and it sucks up a whole lot of system resources doing its thing, making multitasking sluggish. Second: the operating system. The Amiga operating system is a nice lightweight near-real-time message-passing multitasking kernal with a whole bunch of weirdness shoved on top of it. The weirdness sometimes confuses people and gets in the way, but the near-real-time part is ideal for multimedia presentations. A typical presentation, consisting of video and sound orchestrated by, say, a slide-projector-like button on the end of a cord, is relatively easy. You can show an animation and have the music still running at full speed, for example, since you can spawn off seperate tasks for each one. You can also control a laserdisk player while doing all of this, or a MIDI port, or maybe both, I'm not quite sure since I've never had a laserdisk player, and you can be controlling these while your presentation is in progress. All of this is currently-available stuff, that you can either do from scratch or do with currently-available scripting tools such as The Directory, CanDO, or AmigaVision. Third: software. The Amiga has a huge number of video paint packages, ray tracers, texture mappers, titlers, character generators, flippers, transitioners, animators, you name it. From what I understand, on ISA setups you generally are limited to whatever tools come with the board that you buy. On the Mac, you have QuickDraw, which allows device-independence, but the Mac has other problems. None of the Macintosh input devices are interrupt-driven, they're all polled I/O, so responsiveness in a multiple-source environment can be problematic. Similarly, none of the standard Macintosh I/O is DMA-driven, and the standard Macintosh hardware doesn't have any co-processor to offload graphics manipulation. Again, responsiveness suffers when you're trying to do a half-dozen things at once. (Such as, e.g., control a MIDI device and animate a presentation at the same time). Also note that until release 7 of the Mac OS, you had to do a whole lot of kludgery to do two things at the same time, kludgery such as stuffing pieces of code into the interrupts... stuffing code into the interrupts most definitely hurts responsiveness, and can cause music to get off-key if you're taking up too much interrupt time (i.e., you can "lose" interrupts). This has definite ramifications on your ability to be a "multi"-media machine (where "multi" assumes that you're doing more than one thing at once). Compared to Mac and MS-DOS, the Amiga is clearly superior as a multimedia machine. It is possible to get equivalent results from both, but at a far higher cost, and with a certain clumsiness (such as code running in interrupts, etc.) Another system which has been mentioned is the NeXT. The NeXT would be ideal, except that its current release of Mach doesn't have any real-time extensions. This is especially problematic in the case of MIDI, where accurate time-stamping of inputs, and accurate timing of outputs, is necessary to get good results. The jerkiness of normal Unix doesn't bode for smooth animations or smooth control of a laserdisk player, either. The machine has potential. But the operating system will have to be brought up to modern levels of responsiveness in order for that potential to be realized. There's also the software problem, and the problem with getting studio-quality NTSC out of the machine, but neither of those are insurmountable -- third parties can easily handle those. The OS problem, on the other hand, is something that NeXT themselves are going to have to tackle, if they wish to position the machine as a multimedia platform. == Eric Lee Green (318) 984-1820 P.O. Box 92191 Lafayette, LA 70509 elg@elgamy.RAIDERNET.COM uunet!mjbtn!raider!elgamy!elg Looking for a job... Unix/Amiga/C... tips, leads appreciated.