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From: eachus@aries.mitre.org (Robert I. Eachus)
Subject: Re: [xpert...] free video movies
In-Reply-To: kas@cs.aber.ac.uk's message of 19 Mar 91 15:12:24 GMT
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References: <1991Mar15.183911.18550@kodak.kodak.com>
	<1991Mar16.235110.14802@ox.com>
	<KAS.91Mar19151224@gabriel.cs.aber.ac.uk>
Date: 20 Mar 91 14:50:17


In article <KAS.91Mar19151224@gabriel.cs.aber.ac.uk> kas@cs.aber.ac.uk (Kevin Sharp) writes:

   None of popular image formats would be suitable. What you need is a
   movie format.

   One obvious thing you do in a movie format is not to replicate data in
   consecutive frames....

   Sounds like you haven't heard of IFF (Interchange File Format). It
was originally proposed as a machine (and application) independant
structured file format for interchange of multimedia data.  Deluxe
Paint (for the Amiga) was the first application to use it.  It has
since become the format of choice on the Amiga, and is starting to
show up on several other platforms.  Anyway, there are several ANIM
formats, most of which use differences from alternate video frames to
make double buffering easier, but differing in the compression method.
(Using the previous frame instead of the current frame allows a
simpler display algorithm: Only change some pixels in the frame you
are not currently displaying, switch frame buffer pointers, repeat.)

   The current IFF specs are available from both Commodore and
Electronic Arts.  Since it is an extensible format, new "FORMS" are
added every so often.  There are many public domain and commercial
products which use, display, or convert IFF files.
--

					Robert I. Eachus

with STANDARD_DISCLAIMER;
use  STANDARD_DISCLAIMER;
function MESSAGE (TEXT: in CLEVER_IDEAS) return BETTER_IDEAS is...