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From: lindwall@beowulf.ucsd.edu (John Lindwall)
Newsgroups: comp.sys.amiga.multimedia
Subject: Re: CDTV Motion Video
Message-ID: <20414@sdcc6.ucsd.edu>
Date: 10 Jun 91 19:40:23 GMT
Article-I.D.: sdcc6.20414
References: <30764@hydra.gatech.EDU> <19750006@hpmwmat.HP.COM> <31024@hydra.gatech.EDU>
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Organization: CSE Dept., UC San Diego
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In article <31024@hydra.gatech.EDU> jt34@prism.gatech.EDU (THOMPSON,JOHN C) writes:
>What if it would cost a whole lot less to do
>only 256 colors at 15 fps, would this change the impact of the message. Do we
>need motion video at all? 

I have no quantitative results on reduction of video quality vs "impact", but
for my Masters project at UCSD I helped implement a Video Filesystem server.
Beleive it or not, the server ran on a PC-Clone equipped with an audio/video
capture system made by a company called UVC.  The hardware was capable of
displaying ~ 640x480 pixels, with 8 bits per pixel.  The hardware performs
a simple run-length encoding to reduce each video frame to < 64K.  The audio
samples for each frame were tacked onto the end of the video frame (the audio
bandwidth was trivial compared to video, even sampling a 8 KHz).  The server
listened on a socket for requests from any number of clients -- currently we
have an "video editor" application running under OpenWindows on a Sparcstation.

The video sequences played back at a rate of 15 fps (the best we could attain
for this frame size -- basically full screen).  The hardware is capable of
30 fps, but you'd have to reduce the quality of the video (blocky pixels) or
reduce the viewable screen size (half screen).  Even at 15 fps it looked pretty
good.  It was a fun project -- I wonder how much better it could have been if
we had been Amiga based.  Commodore had been in touch with our group about
using A3000UX machines, but it fell through unfortunately.



-- 
John Lindwall			lindwall@cs.ucsd.edu
"Oh look at me! I'm all flooby! I'll be a son of a gun!" -- Flaming Carrot