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==  Full-Motion Video Review                              By: Devophile  ==
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Devophile's CD32 Full Motion Video Review

I really don't know a eniterly huge amount at how JPEG and MPEG
compression work, so do not expect a huge lengthy explanation on
all the facets of digital video compression. All I'm here to do
is to review what I've seen and what I feel is good and bad about
digital video.

THE FUN STUFF
=============

There are many names for video on CD, some are FMV (Full Motion
Video), VideoCD, CDV, DV, etc. They all mean pretty much the same
thing, full video and stereo audio on a compact disc that can be
viewed using a special player.

This works via pretty much the same concept as any other video in
the sense of images. Single frames played back rapidly to produce
the illusion of motion, yeah yeah we've heard it before. But the
amazing thing is, look at the math. A compact disc can store up
to around 660MB of data, or around 660,000,000 bytes. That is a
rather large number. Now, we are presented with problem. How to
cram 132000 24bit pictures onto a single CD.

An average high-quality 320x240 24bit IFF is around, oh, 150K. The
CD32's data read rate is around 300K/sec. That means it can only
load around 2 frames a second, let alone the computing time needed
for rendering these pictures. This is by far not ideal. In order
to accomplish the 30fps rate, you would have to read 4.5MB/sec.
This could be accomplished with a SCSI2 drive, but still rendering
the pictures is still a problem. Unless you go to hardware based
rendering. But who has a SCSI2 drive with a full 32.4 gigabytes
(32,400,000,000 bytes) of data lying around for a 120 minute film?
Not anyone on a middle class budget, I can tell you. Plus, who
ships films on SCSI2 drives? No one that I know of. Big problem.

Still then, if we used IFFs on  CDs, we'd only get around 146
seconds of video per CD. Which means you'd need 50 discs for a
120 minute long movie. You'd be changing discs every 2.4333333
minutes. What about AUDIO? Overwhelmed yet?

Enter: MPEG. MPEG stands for Motion Picture Experts Group.
A bunch of high tech wizards that set out to develope a digital
video standard. They have. It's not too bad. Allow me to explain.

MPEG uses the popular JPEG image compression format to compress
each frame and string them all together for reading/decompressing
and displaying. Those who know what they know about JPEG know that
it takes a long time to uncompress because your computer is having
to emulate the decompression through software. Not fun for your
CPU. That's what hardware based decompression if for. It's fast,
it's furious, it's quality... sort of.

JPEG is known for loss of quality depending on the compression
level. MPEG uses a rather high level of compression to achieve its
goal of 74 minutes of video per CD. Thus, much image quality is
lost. BUT, we regain the quality playing chance with 30 frames per
second. Hoping that the lost details in the previous frame will
appear in the next. Usually it works out quite well - sometimes it
doesn't. We'll get into that later.

For those who are interested: MPEG1 compresses audio/video to
around 4K to 5K per frame. Resulting in about 132000 frames per
disc, or 4400 seconds, or 74 minutes. The CD32 can easily read the
150K of data per second used by MPEG, as could any good single
spin CDROM. This is a good thing. What's the bad thing?

Decompression. Think about it. Decompressing 150K of MPEG into
around 23MB of image data per second is no easy task. That's what
hardware decompression (as stated above) if for. Amazing isn't it?
The FMV cartridge for the CD32 is designed for the sole purpose of
decompressing MPEG data. It's very fast. Very VERY fast. All those
numbers to crunch. And for only $299US, it's a steal almost. If
you like watching CD videos.

THE MOVIE STUFF
===============

So far, I've got around 4 CD movies. All of which display a wide
spread of good/poor qualities. Star Trek 5, A Fish Called Wanda,
Sliver, and The Hunt for Red October round out my list. I've seen
Star Trek 6 on FMV, it's comparable to 5.

Star Trek 5: Quality is perfect in nearly every aspect. Most of
             the film is better than VHS quality. Very crisp,
             clean, and well done. Good job Paramount!

Fish Called Wanda: Very nice, indeed. Same as above. Excellent
                   quality.

Sliver: Aside from being an excellent movie, this film's
        conversion to CD Video is slightly less than the above,
        it has very strong points, and is mainly better than VHS
        in all aspects except for an occasional "block" in a
        facial display, the colours mixed improperly. But it is
        not something that the average Joe would notice. Quality
        in all respect!

Hunt for Red October: Stinker. Good film ruined by crap convert
                      to CD Video. The whole movie appears out of
                      focus, grainy, blurry, etc. The underwater
                      scenes are blocky as hell. What was
                      Paramount thinking? They score VERY low on
                      this one. This conversion ranks around the
                      same as an EP quality VHS dub!

USING IT
========

The cartridge simply plugs in the back of the CD32 unit. It is
nearly flush with the back of the case and has no cords/wires.
Seamless.

To use it, simply put in a CD Video and reset the machine. It takes
it from there. You will be escorted to a nice GUI where you can
select the tracks you wish to view. Great job.

Bad job: C= did not make it so it recognises CDI's "chapters."
On a CDI machine you can jump to a "chapter" in the film, chapters
are listed in the CD case's pull-out. This is very handy. CD32's
lack of support for this feature is a very low point. But beggars
can't be choosers, eh?

THE VERDICT
===========

Most are very good, and you usually will not go wrong. Watch out
for first generation films. They were put out in a hurry and they
certainly show it. But in most films, you will be pleased.

I particularly enjoy the freeze frame and slow-mo, very crisp and
sharp. Excellent.

If you are an avid fan of getting new technology, I urge you to
get one if you can find it. If you are not a fan of the "latest"
hardware, but have $299US to spend, get one if you can find it
and hope it becomes a "wave of the future." If it does, you'll be
in the know first and be the envy of all your friends!

Unless you fall into a catagory above, getting a FMV cartridge is
probably not something you want to do at this point. When and if it
catches on, devices will become cheaper and more widely used - then
you should get one. Until then, just hang out at the dealers' and
watch theirs.

As for me, I've gotta have it - I'm "in the know" you know. And
it was a big ego-device for my CD32. I got it because it's there
and I am so desperately hoping to be on the tip of a new iceberg.

PROBABILTY
==========

It probably wont catch on, but don't quote me.

Thanks for putting up with this review. Feel free to ask me for
more info on FMV. I'm not an expert, but I can answer most
small questions.

  - Devophile
    email: devo@gonix.com
    irc: Devophile channel: #amiga
    thanks to: oleg, jkay, rst38h, and anyone else who offered
               info to "fill in the gaps" on my jpeg knowledge.