🚀 go-pugleaf

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.