encryption and compression

[screwedn2]

how come wmp and meg files are only reduced to a minimum when they are encrypted and compressed?I have tried winzip/winrar/and power arc.under the strongest compression setting (and varied encryption settings)with only minimal compression.its becoming depressing any good programs or advice out there?

[ss2chef]

most "binary" files don't have any information for your zipping software to compress.
Usually they are in a compressed format when compiled or created.

[cacosapo]

Although i can pass as a dumbass here, i cant see how encrypt and compress a file after will be better than just compress the file. In fact, due to the nature of encryption, encrypt a text file and compress after will produce a bigger file than just compress it.
Or i missed something? (it happens often)

[screwedn2]

This is from the winzip site itself:I Dunno i was hoping there was a trick or tech or program somebudy knew of that could do the job .......................................................................................... Some types of files compress better than others.For example, various multimedia files are already highly compressed because the standards for these file types specify efficient techniques to compress the data they contain. Examples include files in the graphics (picture) file formats GIF and JPG, MP3 music files, and MPG movie files. Once a file has been compressed, it typically can't be compressed again to any significant extent. Therefore, such files don't get very much smaller when they are added to a Zip file.

You would see similar results if you compressed some files into a Zip file using maximum compression, and then compressed that Zip file into another Zip file. The second archive would not be appreciably smaller than the first one (it might even be a little bigger). This is because the data in the original Zip file is already compressed and can't be compressed again.

There are other file types that don't compress well. For example, certain types of encrypted data files such as those maintained by home finance programs and some database products can't be compressed very much.

By contrast, some types of data (such as text files and picture files in the BMP format that the Microsoft Paint program uses) can often be compressed by 90% or more; some types (such as program files) are often compressed by 50% or so. But if you see files that can't be significantly compressed, it's probably because they already contain compressed data or they are encrypted.

[screwedn2]

i guess perhaps a video converter then go ahead and archive it?

[Vorlin]

Video and most audio files (mp3, etc) don't compress well at all because compression requires reading similar data (instead of writing 8 e's in a row, it can do 8e, example only) which isn't that prevalent in these types of files.

[screwedn2]

Dr DivX to the rescue YaY!!I just compressed an 80 mb file to 9mb

[Vorlin]

Right on...converting a file would be the only method, I would think, unless some new technology is out there. It's like I used to think tar and gzip in *nix were the only ones but bzip2 is much better.

[therenegade]

DivX is a great utility for compressing video files,but I'd check up on whether it has any spyware components shipped with it..I seem to recall a few people saying Gator installs with DivX..try to get a clean install if possible(from www.divx.com I presume)

[annihilator_god]

The free divx stuff does come with spyware and ads... unless you only want the codec, which is free, but you have to scour the site to find it. Since dr Divx is a pay program ($50 if memory serves me) there are no spies or ads (I hope, I've never used it). What about Xvid? I heard it was open source, so the compression program must be free (if under the GPL, and maybe only the code). But again, i'm not into compressing video files so i have no experience.

What i do know is that the divx compression does come with some drawbacks, you lose audio and video quality as the file size becomes smaller. Sometimes you just have to play around to get the right balance. You just have to take the playing medium into account (pocket PC with a little mono speaker, or movie that you want to play fullscreen on your 1337 gaming rig). Or problems with moving the media to the other device. i bet your friend doesn't want to download a 50mb movie from his mail server.