Compressed Folders Not Compressing Files

[Pez D Spencer]

Since I only have a 80GB HDD to deal with right now, space is at a premium. To overcome this I compressed folders which have my game ISO's, MP3's, Photos, and the Temp folders for emule and bit torrent. The problem is that it's not really compressing them that much. My only guess is that (at least in the case of MP3's), is that since MP3's are already compressed, NTFS compression can't really do much with them. I suppose this also applies to the folders with all my ISO's in it too. Am I right about this or what? I've tried uncompressing them and recompressing them again but the results are the same. I even tried to put them in a RAR file with the best possible compression and the results were minimal. Any help on this would be appreciated.

Of course a simple solution would be to just get another drive but I'm low on cash and don't have a CD or DVD burner right now because mine took a dump on me.

Here's a few screens so you can get an idea of what I'm talking about:
http://tinypic.com/view.php?pic=339ndcj
http://tinypic.com/view.php?pic=2e6926w

Any ideas or help is appreciated. Thanks.

 

[bsobel]

You really answered your own question. NTFS compression isn't some magic compression that will take content you already compressed (say MP3) and compress them even further.

If it COULD do that, dont' you think the folks developing the MP3 format would have alrady done it....

 

[bersl2]

Quick compression lesson: the more repetitive information tends to be the most compressible. Plain text compresses very well, as it is usually a limited set of characters laid out in repetitive patterns. Binaries (i.e., executables) generally don't compress as well, because such information is more random, though there are often still enough patterns to make it useful on occasion. JPEG and MP3 files are compressed so much that their algorithms, due to the specialized nature of that type of data, throw out information whose absence is least likely to alter our perception. Many archive formats are also compression formats, and trying to compress what is already compressed is of marginal value at best; at worst, in some (mostly pathological) cases, doubly compressed files are larger than before.

Compression isn't magic. Well, maybe it is, but it still has limitations.