Crazy Compression?

[BuzzKillington]

Some of you may be aware of "Skullptura"s method of compressing files and I'm curious as to how he does it. The skill alone intrigues me and I'd like to play around with it.

From what I can see, he does it through DOS. I'm not exactly sure how to reverse engineer a Bat file so I honestly haven't the slightest idea how or where to start.

Help?

[p0Pe]

f##k dos, get a slegdehammer.

honestly, i dont know:D

[BuzzKillington]

Anyone? (thanks for the move)

[Mach]

From what I google, its based on the 7zip dos engine. Some report that the files are just highly compressed; others that the video or images are downsampled and multi-language as well as extras have been removed.

You do realize that it is a group of folks <snip>. Personal opinions aside, this thread will likely receive a delete because it a) violates house rule #1 b) attracts the wrong kind of attention to TBCS.

House Rules:
http://www.thebestcasescenario.com/forum/showthread.php?t=7312

[BuzzKillington]

I never mentioned anything about <snip>, <pillage>, etc. I was simply curious about his method of space saving.

EDIT: I'm just going to go ahead and do what he did.

[Mach]

Fair enough. Speculating here, but the crazy compression that they're getting appears to be a function of 7zips "ultra" lossless compression algorithm applied to large target files which are optimized for performance but not size; as well as selective lossy compression of music, video, and image files before 7zip-ing. Not sure if the extract is hand rolled or automated via one of the variant/add-ons of 7zip. Likely the latter, as this is not one individual.

If you compare the uncompressed source files to the compressed altered files, you should get a good idea of how much is lossless vs lossy vs missing files.

I'm going to edit my previous post to remove offending references not related to compression. The overall concern is that TBCS gets blacklisted due to offending keywords during routine indexing (ever wonder why there is so many guests online?). Consequently TBCS'ers can't access the site from work or other ISPs that aggressively filter the internet based on blacklists.

[BuzzKillington]

Thank you, I'll have to look into it. I still don't grasp the concept of compression. How does an application take something... cut it's size... then have it be there again. Basically what I'm asking is how can you shrink a bit then make it return to a bit.

On top of that, there are many difference compression apps out there but they're all different. What method is it that allows bits to be shrunk and how are there different methods to begin with?

I found a very interesting read here (http://www.unet.univie.ac.at/~a0503736/php/drdoswiki/index.php?n=Main.Compress).

[XcOM]

Check this page out (http://en.wikipedia.org/wiki/Data_compression)