(note i never used GIMP-GAP)
it probably stores the video as a sequenc of seperate images becouse that
makes editing a 1000 times simpler. It alse means there is no
frame-to-frame compression so the resulting animation is just as big as the
input images, unless you set it to a lower quality.
these days I juse a simple linux command:
ffmpeg -hq -b 1000 -i "filename%3d.png" -y "filename.mpg"
(high quality, 1000 kbit/s)
