Re: color video?

T.Dorcey@cornell.edu
Sun, 18 Sep 1994 12:41:30 -0400


>I was wondering: how possible is it to have color video conferencing over the
>Internet?
>
>You see, one of the most popular postings in alt.binaries.multimedia recently
>are several clips from the Disney movie "Lion King" One particular clip of the
>stampede is 80 seconds long. It is full color, 160x120 pixels, with 8bit 11KHz
>audio. The size of the whole file is 2.9 megs. Dividing by 80 seconds gives a
>rate of about 36Kb/s
>
>Since CUSeeMe currently transmits at about 60kb/s or higher, it seems that
>color video may be available in the not-too-distant future.
>

First note that network transmission rates are typically measured in
kilobits/second (kbps) not kilobytes. So, the file you describe would
actually require 297 kbps to transmit. More importantly, videoconferencing
demands compression/decompression in real-time. I doubt that the
compression ratio you observed with the Lion King clip could be achieved in
real time on a typical Macintosh or PC. An additional complication is that
data may be lost in transit on the network, so any video coding technique
must account for that.
This is not to say that there won't be color available in the
not-too-distant future. Just don't expect the video to be as good as the
Lion King clip, and recognize that you will pay some price in reduced frame
rate or reduced spatial resolution if you want to transmit color.

-Tim
__________________________________________________________________
Tim Dorcey T.Dorcey@cornell.edu
Sr. Programmer/Analyst (607) 255-5715
Advanced Technologies & Planning
CIT Network Resources
Cornell University
Ithaca, NY 14850
__________________________________________________________________