testing avi/hash code is on page I gave a link. But Anyway, I did this:

open outFile, ">", "test.txt";
print outFile ' ' x (65536 * 4);
close outFile;
#hash is: 08080808080c0000
[download]

I know this hash technique is not strong, but I can't do anything about it. It is same as Media Player Classic is using.