Re: Apple2 QuickTime (commencing project)

[Scott.Alfter@skunkworks.genesplicer.org (Scott Alfter)]

In article <52988@f10.n209.z1>, Andrew Kingdom <agk@bbs.ausom.oz.au> wrote:
>My next project for the II is going to be a movie (probably
>QuickTime) player.

This sounds interesting. :-)

>The obvious limitations I'm going to
>have to work around are:
>Slow CPU, 

True, even with an accelerator.  I'd suggest that you handle any kind
of compressed animation (QuickTime, MPEG, or whatever) in two passes.
The first pass would decode the image and store the raw data to disk.
The second pass would dump the uncompressed data from disk directly
into the frame buffer.  With a RamFAST or Apple DMA SCSI card and a
good hard drive, you should be able to get fairly good animation this
way (one of the people who worked on the Apple DMA SCSI card put
together a demo for the card that showed (in B&W) the Death Star
tunnel chase scene from _Star_Wars_; this was said to be a fairly good
demo, and I think it ran on an unaccelerated GS).

>Low end graphics,

Most animation files use a fairly small frame, such as 160x120 or
240x180.  On a IIGS, the frame will only appear larger than on another
machine.  4-bit grayscale isn't the best in the world, but it isn't
too bad.

>Limited memory,

If you spool the uncompressed data to disk, this shouldn't be a problem.

>and Limited disk storage (for 5.25 floppies that is).

Forget about floppies of any kind; not only are they not big enough,
but they're also not fast enough.  A big hard drive is pretty much
required for any kind of animation, especially if you're going to
spool uncompressed data to disk.  Sending uncompressed data to the
screen would present less of a disk load, but even an accelerated GS
would probably be way too slow.  I've viewed MPEG files on a 386SX-25
under DOS and have only gotten 4-6 fps when the file was uncompressed
directly to the screen.  Uncompressing to disk and viewing the
raw-data file (on the same machine) yielded frame rates closer to
10-12 fps.  (A DECstation 5000 can decode directly to the screen at
high frame rates, but you're looking at high-end hardware (MIPS R4000,
if I'm not mistaken).)

FWIW, I'd find an MPEG viewer more useful than a QuickTime viewer.
There's very little QuickTime material out there, compared to what's
available in the MPEG format.  Also, free MPEG codec source code is
supposed to be available somewhere; this might get you going a little
more quickly than if you have to conjure up an algorithm from scratch.

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