Thank you.
I wrote a simple multi video script to automatically acquire ten 20 minute segments of video on my sx30is.
20 minutes seems to fall below the 4 GB limit I have encountered.
Unfortunately, it does seem to require a 3 second sleep to stop the old and start the new video.
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@title Multi Video
print "Start Multi Video"
click "video"
sleep 3000
for i=1 to 10
click "video"
for j=1 to 1200
sleep 1000
print "f",i,"of",10,"s",j,"of",1200
next j
click "video"
sleep 3000
next i