doubtful.. unless most of the file is empty, or if a media file or picture, mostly one color. most modern compression algorithms look at the first pixel, then the next, so on. if, suddenly there are say, 200 red pixels in a row, (a picture of a rose), the algorithm just says "ok, 200 red. next?" instead of going "red pixel, red pixel, red pixel, ....so on". ok. with that in mind, for video, the algorithim looks at the first frame, then the next, and subtracts the second from the first to see what has changed. video with lots of movement (changes) will then tend to be larger than a 2 hour video of your dead grandmother in her coffin (hey, i don't know... maybe you were making sure before you hit the will.) so, in essense, if you're trying to compress a file with lots of changes, you're out of luck. hope this helps have fun.
