RE: small, grey squares

Wed, 14 Sep 1994 10:00:52 -0400

The small grey squares you see are areas of the picture that have not been
updated since
you began your session. The reflector only transmits areas of the image
which have changed.
The reflector does this by breaking the image up into these squares and
comparing each square to the square from the previous image. If the pixels
in that block are equal, then that block is not transmitted. This is a
simple form of image compression. The blocks you see are normal. If every
frame was transmitted in its entirety, there would be no bandwidth left for
other users, or
the frame rate would be too low to recognize as motion video.

Hope this helps,

Byron Jones
Office of Admission
University of Miami

-- Generation-X will be the first generation unable to afford
-- .sig files better than their parents...

From: cu-seeme-l
To: Multiple recipients of list
Subject: small, grey squares
Date: Tuesday, September 13, 1994 11:12PM

Can anyone tell me why, when I recieve video from reflectors (I cannot send,

yet), the image is covered, in places by small, grey squares??? Sometimes,

they coelesque and block out large areas of video, other times they stand
alone. Every time, however, they are there.


Mark E. Berkman
The Ohio State University
(614) 688-7532