Invisible wrote:

> It all sounds a bit silly today. We tak such things for granted.
> 
> We are truly living in the future, my friends...

When you think about it, it's kind of like the industrial revolution...

The industrial revolution transformed the way mankind lives and works. 
It altered the economy forever. Fortunes were made and lives were 
ruined, and the world has never been the same since. You can argue about 
whether all these changes were for good or ill, but none can deny that 
society was transformed. Things which would hitherto have been 
considered impossible because quite ordinary.

But nobody really even thinks about the industrial revolution now. 
Because it's *happened*. It's *over*. We're *here* now.

I guess it's the same with the digital entertainment revolution - nobody 
really thinks about it any more because it's old news now.

Heh, I'm old enough to remember actual green screens. Computers that 
tried to play "music" by making beeps. Images that were a mass of 
multicoloured square blocks. The idea of a computer *so powerful* that 
it could show pictures that looked almost photographic seemed 
mind-blowing and futuristic.

Today, it's a mundane reality. Sure, you can now play a movie on your 
computer as well as on your TV. And how is that really different? It 
turns out that once you get over what a neat idea it is, the reality 
isn't so different to VHS.




Actually, at the weekend I was reading an article in Amiga Format. This 
was the April 1994 issue, and they're talking in hushed tones about a 
visionary new technology dubbed "Full Motion Video" (FMV).

The article goes on to explain that since it's now possible to store 
computer data on a CD (something they call a "CD-ROM"), in theory you 
could be able to store a computer animation on there. And since the 
Amiga can produce near-photographic image quality... hey, what if you 
could put a *movie* onto a CD??

Ah, but there's a catch. One frame of high-quality video takes up about 
1 MB of space - and you need 25 of them for a single second of video. 
That gives us a transfer rate of 25 MB/s, which *wildly* exceeds what 
any known CD drive is capable of.

(By my arithmetic, a CD gives you 10 MB/min, so 60x faster would be 10 
MB/s, and another 2.5x faster would be 25 MB/s. So we need a drive that 
spins at 180x normal speed. IIRC, normal CD speed is 500 RPM, so that's 
90,000 RPM. The *centrifuge* in our lab doesn't spin that fast. Hell, my 
*car* doesn't rev that high! The disk would surely shatter due to the 
extreme centrefugal forces...)

But there's a bigger problem than transfer speed: 650 MB / 25 MB/s = 26 
seconds of video (!!!), without any sound. Who the hell is going to 
bother putting together a high-end system so they can play 26 *seconds* 
of video on their computer?

It is crystal clear at this point that the storage requirements *must* 
be reduced. The data has to be compressed somehow. But as soon as you do 
that, the difficulty is finding a way of compressing the data so that it 
can still be UNcompressed fast enough for realtime playback. This is a 
serious problem.

Apparently Phillips has come up with a new device called the CD-I, which 
usees the "white book standard". This basically means you take your 
movie, downsample it to half resolution (so it's roughly 400x300 
pixels), and then encode it using a newly-developed system known as 
"MPEG". You then put this on a CD-ROM.

Trouble is, the latest high-end Amigas had MPEG decoding software, but 
would only manage maybe 3-4 FPS at low resolutions. This is clearly 
insufficient for FMV! But then there was the Amiga CD32.




For those that don't know, the Amiga CD32 is an Amiga 1200 with a CD-ROM 
drive, built in the shape of a games console. (There's no keyboard or 
mouse, for example.)

Most of the games released for it were actually just Amiga 1200 games 
with a CD soundtrack added. But a small few actually took advantage of 
the awesome storage capabilities of a CD-ROM. (Remember, previously 
games came on 720 KB floppy disks!)

In this same issue of AmigaFormat, I read an issue for a game called 
"Microcosm". Due to some sci-fi plot that isn't actually that 
interesting, you get put inside a space ship, miniturised, and injected 
into somebody's body to fight off a hord of robits inside the guy. In 
other words, basically you fly down organic-looking tunnels shooting things.

I don't have the magazine in front of me now, but the final summary read 
something like

   "This may not be the most playable game ever, but it doesn't even 
matter. This game is the future. And it's here right now. GET IT!"

The best screenshot I can find is this:

http://www.lemonamiga.com/games/screenshots/full/microcosm_(cd32)_20.png

The graphics were comparatively realistic. Certainly little like this 
had been seen before. Most games were either cartoonish platforms, or a 
few were very slow, jerky 3D things with giant polygons, point lights 
and no surface texturing. *This* looked almost real.

(In solomn truth, it's actually just a 2D game with a prerendered 3D 
background loop playing behind it. But it *looks* impressive. And it's 
only possible to fit that much animation data in due to the cavernous 
space on a CD-ROM.)

It was also intercut with smooth video sequences:

http://www.lemonamiga.com/games/screenshots/full/microcosm_(cd32)_03.png

Certainly it's nothing compared to what we have today, but back then 
seeing bits of jerky motion on a *computer* was astonishing.



Anyway, getting back to FMV... There was a [very expensive] card for the 
Amiga CD32 that allows it to play any White Book compliant CD movie. 
Phillips were apparently very surprised when they found out about this. 
But they seemed pleased. "I think anybody who does with producing a 
proprietry format has the wrong idea. We need a common format to 
stimulate adoption."

(Anybody who remembers the HD-DVD/BluRay feasco surely cannot doubt 
these words!)


custom MPEG decoder hardware. The magazine mentions how "it takes many 
months of running time on the latest supercomputers to convert video to 
MPEG format". But, "amazingly", it makes the data fit onto a CD and play 
back even within a CD's limited transfer rate.

The article is of course liberally decorated with screenshots from an 
Amiga playing various movies. I've never heard of CD-I or the White Book 
standard, but apparently quite a number of titles were actually released 
for it.

The pictures don't actually look bad at all. If anything, the only real 
problem is the very low spatial resolution. They all look kinda fuzzy 
and out of focus, and very pixelish. (Remembe, this is 400x300 pixel 
resolution!) But the *colour* seems completely perfect. There is no 
*hint* of the MPEG artifacts you often see at high compression ratios.

When did DVDs come out? I don't actually know the answer to that, but it 
seems like comparatively recently. To think that the Amiga was already 
*doing* this stuff, for real, way back in 1994 seems quite impressive to 
me. Not that it apparently got very far...



How are things different today? Well today we have DVDs, which are just 
like CDs except with significantly more storage capacity. That means you 
don't have to downsample the video to make it fit on a disk.

But more importantly, today a cheap PC can decode MPEG completely in 
software, and the CPU is *idling* during this task. It's *easy*! And I 
think that's the key thing. The computer power necessary for realtime 
video decompression is now commonly available, which is why you can go 

machine for that price! EVER!

(I guess all those complicated robotic parts for spooling the tape and 
so forth were just inherantly expensive to make. A DVD player just needs 
a few motors, a laser, and a computer with some software. It's quite 
easy really...)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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