[A83] Re: Video compression

To: <assembly-83@lists.ticalc.org>
Subject: [A83] Re: Video compression
From: sebastiaan@rimsystems.nl
Date: Wed, 14 Mar 2001 20:46:53 +0100
In-Reply-To: <000101c0aca8$a8951680$6510c5d5@dsfs98>
References: <000101c0aca8$a8951680$6510c5d5@dsfs98>
Reply-To: assembly-83@lists.ticalc.org
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Adding more/better compresion probably isn't very good for the speed (BUT a 
slower decompression needs less frames to keep te video-stream at te correct 
speed --> less frames, less data, smaller video-files ;)

> 
> Another small question from the Netherlands coming in:
> 
> can anyone give me more techniques for compressing video and still
> images in
> Z80 assembler? As you might now, I'm the author of TItanium MultiMedia,
> which converts Windows and Quicktime video's to your TI83. The current
> compression system is in my opinion the most reliable and compact, but
> maybe
> someone has more ideas for it?
> 
> the current compression works like this:
> 
> - convert the source frame to a 96x64x2 format using dithering
> - RLE the B/W 96x64x2 screen
> - RLE the difference (pixels that were modified since last frame) B/W
> 96x64x2
> - check if the 'full' screen is bigger (size :-) than the 'difference'
> screen and save the smallest
> 
> decompression is simple:
> 
> - check if the frame is 'full' or 'difference'
> - if it is 'full', unpack it to @plotsscreen
> - it it is 'difference', unpack it to @saferam1 and XOR it with the
> current
> data @plotsscreen
> 
> If you haven't looked at TIMM yet, please do. Anyone having ideas about
> this, please share them with everyone. I will credit everyone with
> substantial information in the readme and info dialog. Thanks in
> advance!
> 
> yours sincerely,
> Frank Schoep
> ====================
> Forever For Now
> http://foreverfornow.cjb.net
> dsfs98@concepts.nl
> ====================
> 
> 
> 
>

References:

[A83] Video compression

From: "Frank Schoep" <dsfs98@concepts.nl>