How to compress a file?

[Dvorjak]

So I want to compress an 11gb file, but can't figure out how to do so. I tried winrar and winzip and tried to compress it with windows 7, but whenever the compression is done, it's still 11gb! It didn't compress anything. The reason I want to compress is because I want to transfer it onto my 16gb flash drive. For some reason whenever I try to transfer it, it says the file is too large, even though it's not. I reformatted the drive as well.

[Jurwi]

It's possible that your file is already compressed so you can't really get it any smaller.

About the flash drive, is it formated as FAT32? If so, maximum file size you can put on it is 4GB. format it into NTFS if you can.

[Dvorjak]

Thanks, it's fixed.

[ispano]

What Hinaaja said pretty much. If it's a movie or whatnot, likely it's already compressed as far as it's going to go. And typically the default format for a 16 gig drive will be FAT32. You can format it NTFS and get around the 4GB limit. The only issue that I can think of with that is if you are wanting to watch said movie on an xbox 360, which cannot read NTFS.

[Deleted]

You can't really compress a movie file (say, avi or mkv)

[vesseblah]

Cant compress WoW's MPQ files either because those are encrypted. File encryption makes further compression fail since the contents are essentially random.

[Nathanyel]

It's not the encryption (not that the MPQs have notable encryption, but they are indeed compressed)
At most an encryption can affect the compression rate of files with plain text, as that is easy to compress since it has recurring character sequences, say words or parts of words. When that is encrypted, however, that data is jumbled, and the compression software cannot determine as many recurring sequences, hence the compression rate is worse than for the unencrypted version. But that should only affect (sets of) files that are very large and contain a lot of text.

[vesseblah]

At most an encryption can affect the compression rate of files with plain text, as that is easy to compress since it has recurring character sequences, say words or parts of words. When that is encrypted, however, that data is jumbled, and the compression software cannot determine as many recurring sequences, hence the compression rate is worse than for the unencrypted version. But that should only affect (sets of) files that are very large and contain a lot of text.

Nop, proper encryption produces data so random that it's uncompressable. It does not depend source material, but the quality of the encryption algorithm.

Randomness is one of the requirements to make it harder to reverse, not being able to compress it is a side-effect.

[Nathanyel]

Nop, proper encryption produces data so random that it's uncompressable.

That's what I meant However, uncompressed data is usually as "random" as encrypted one, unless it's plain text. Well, technically, all video/audio data is 'encrypted' as well, by the codec.

[Brett Skullcrack]

However, uncompressed data is usually as "random" as encrypted one, unless it's plain text.

No, if that were true then compression of anything except plain text files would be impossible, which it's not.

Well, technically, all video/audio data is 'encrypted' as well, by the codec.

No, it's not encrypted, it's encoded.