zipping

Majinronin · Post by **Majinronin** » Tue Apr 29, 2003 8:09 am

how exactly can i compress a movie so that it isn't as large a file. right now i compress a music vid but it stays the same size. help, thanks

Ashyukun · Post by **Ashyukun** » Tue Apr 29, 2003 8:20 am

This would likely go into software help and not hardware...

If you're trying to compress a video encoded with an already compressed format, you're not likely to get more than a few percent (if that) out of the .zip, .rar, etc. because the data you're trying to compress down has already been heavily compressed. Zip, Rar, and the likes are all lossless compression formats- when you uncompress the file, it has to be exactly the same as before it was compressed. We already employ lossy video compression formats (for distribution) like DivX, MPEG, and MJPEG to squeeze videos down even smaller- it's generally safe to assume, I believe, that another (lossless) compression routine wouldn't be able to compress it down much more.

Think of it like crushing an aluminum can in two can-crushers, both that work pretty much the same way and have the same power output. After you compact the can in the first, you take what you have left (the compressed can) and put it into the other can-crusher. You're not likely to get it any more compacted by using the second one than you did out of the first...

Sometimes, you can get a couple of percent compression, and if that's what you need, go for it. But generally, I don't think it's worth the time to try compressing it down or the time whoever downloads the video (assuming it's for distro) has to spend uncompressing it before they can watch it.

Majinronin · Post by **Majinronin** » Tue Apr 29, 2003 9:48 am

ok, thanks for the detailed reply, sorry this is the wrong board though