How to update movie in run time avoiding crash

1
Dear Psychtoolbox users,


I'm using the toolbox to study motion perception.
My experiment requires to update the stimulus movie
in real time. For example, I used the following loop.

for Loop = 1:1:10
for i = 1:1:40;
compute movie
imagePtr(i) = SCREEN(window,'OpenOffscreenWindow',[]);
end
for i = [1:1:40];
SCREEN('CopyWindow',imagePtr(i),window, rect1,
Rect1,'srcCopyQuickly');
WaitSecs(0.04);
end
end

My computer keeps crashing. I'm using a G4 450 with 256MB
built-in memory and 900MB virtual memory on Mac OS 9.

Any ideas to fix this?

Thank you,

Zhiyong Yang

Department of Neurobiology
Duke University
yang@...