🚀 go-pugleaf

In article <1992Jul24.203347.27701@kronos.arc.nasa.gov>,
aseem@kronos.arc.nasa.gov (Aseem Das) writes:
> I am interested in buying a complete multimedia PC or Mac.  I would like
> to be able to grab video/TV, compress the grabbed movie togather with
> sound, save it on the hard disk and then later be able to play it
> as needed.

I'd say the Mac is the only platform with widespread support for this sort
of thing at the moment. Apple's QuickTime software includes the image
compression services, movie editing/playback, and video frame-grabbing
services that you need. And there are lots of applications already available
that make use of QuickTime.

> Having very little knowledge of multimedia, I would like to know:
>
> 1. What hardware do i need (audio boards, video boards, frame grabbers etc.)

Basically you can spend as much as you like, or (almost) as little as you
like. The two best-known names in Mac-based products are SuperMac and
RasterOps. RasterOps sell a range of cards, up to the fabulous (and
expensive) 24XLTV, which is a display card that gives you 24 bits per pixel
on a 21-inch colour monitor, with a resizable real-time video window. SuperMac
are having a lot of success with their low-end VideoSpigot card, of which I
happen to own one.

Both companies have announced cards that will do real-time compression and
decompression of full-screen, full-frame-rate video. I recall seeing a
notice on AppleLink that SuperMac would be showing their card at Boston (?)
Macworld next month. However, neither company is as yet actually shipping their
compression cards, as far as I'm aware.

As for sound, I'm not familiar with the CD-quality audio cards, but I
gather there's quite a price jump on the Mac from 8-bit-per-sample audio.

> 2. What software do i need (compression software, multimedia authoring
systems)

With QuickTime on the Mac, you can use a range of applications with different
capabilities, and exchange data between them. The two products I'm aware of
for editing of digital video movies are Adobe's Premiere and DiVA's VideoShop.
MacroMind Director (should that be MacroMedia Director now?) is a well-known
animation package, and version 3.1 (which I gather is already available)
includes direct support for QuickTime, including, I imagine, the ability
to export an animation sequence as a QuickTime movie. With version 3.0,
I do this with a separate utility.

And you can use QuickTime movies in presentations with a range of applications.
Claris have available a set of externals for doing things with QuickTime
from HyperCard; other applications with QuickTime support (either standard
or as an add-in available from the vendor) include WordPerfect 2.1, Microsoft
Word 5.0, Mathematica 2.1 and Canvas 3.0.4. An interesting system hack
called Wild Magic lets you bring QuickTime movies into a bunch of other
applications that only know how to display QuickDraw pictures.

> 3. How is the functionality divided between the hardware/software.
> For example, Is there hardware which does image/sound compression?

With QuickTime you have the choice. The basic QuickTime software includes
software implementations of JPEG compression, plus a couple of Apple-proprietary
image compression schemes that are designed to give fast decompression without
extra hardware. It's easy to plug in additional compressor algorithms or
alternative implementations of existing algorithms, including add-on
hardware boards, in a fashion that's transparent to QuickTime-compatible
applications.

The standard Mac Sound Manager includes software-based compression that
can give you either a 3:1 or 6:1 space reduction at 8 bits per sample.
I wouldn't recommend using these for anything other than voice; also if
you're playing back a movie on low-end hardware, the CPU time spent on sound
decompression will probably take time away from the video compression,
resulting in jerky video.

> 4. What is the compatibility between the different hardware/software
> products?  Can i use software X with hardware Y?

On the Mac the answer to the second question is generally "yes". The
basic data interchange formats are QuickDraw PICT (for still images),
two or three different sound file formats, PICS (a very simple format
for animated picture sequences) and QuickTime movies (which can contain
both sound and video). As for video digitizers, I'm not aware of a vendor
which *doesn't* now support the standard QuickTime interface.

> 5. What excatly does a MMedia authoring system allows you to do.  Is
> it like a UI builder, lets you incorporate images/sounds etc. into a
> toolkit.  What are some of the good MMedia authoring systems?

Here's where my experience is, shall we say, a little more narrowly focused
than some other people. :-)

Most of my work is done with HyperCard. I use this as a "user interface
engine"; it includes some handy built-in facilities, like paint tools,
storage of text data with basic text searching, custom menus and buttons,
and a programming language. But it's also extensible, in that I can write
code in a conventional language like Pascal or C, to perform some useful
function, and then invoke this code from HyperCard. This way I can concentrate
on providing a set of useful, general-purpose extensions, and use HyperCard
itself to implement the details of the user interface (which anybody else
can change if they want to).

There are systems specifically designed for things like building courseware;
if this is the sort of thing you want to do, then you would be better off
using one of them rather than HyperCard. However, in my opinion none of them
is quite as flexible and extensible in such powerful ways as HyperCard.

Just my five cents' worth (we don't price retail things in odd cents in NZ any
more :-)).

Lawrence D'Oliveiro                       fone: +64-7-856-2889
Computer Services Dept                     fax: +64-7-838-4066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+12:00