Winrar compression question 500mb down to 2mb how?

[Majestic_twelve]

I was just wonder how do people manage to compress files so small useing winrar. I recently download 63 files approx 2mb to 30 mb in sizes compressed in winrar self extracting exe's. after I extracted them they ranged in sizes from 500 to 700mb each, how is it possible to compress things so much. I own winrar 3.0 and have never been able to achive such compression.

I would include one of the exe files as an example but they are compressed playstion iso's and I dought they are allowed on this board, so I will not post them.


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[mafiafromrussia]

also not all files compress at same rate. some may be compressed more some less. like mp3 files, u cant really compress them any further i think.

 

[Majestic_twelve]

I am going to compress iso's approx 400~650mb in size but the highest I can compress them is to approx 60~80mb in size. I tried toggeling all the settings in winrar but no luck in compressing them any smaller. Which is ok since I don't do alot of compressing myself I was just curious how some people reach such high compression rates.

 

[mafiafromrussia]

just something i recall from a long time ago, but in rips, myth class groups used some uharc thing to compress files. as i've seen it packs a lot of stuff. i'm not sure if it's right though

 

[SPeedY_B]

Rar Compression is based on repetetive character strings in files.
as a random example a Dreamcast iso i downloaded (a legal emulator one ) was roughly 6mb in size, yet the iso contained a 640mb-ish dummy file which uses the same ascii over and over in a file to push data on the CD to the edge (a dreamcast loading method) so the rar file was around 7mb!


as far as i know Uharc is only sound based, ie it compresses wav files into mp3 for a nice small distributable package, then un-packs them again at the other end.

 

[blinden]

I agree with SpeedYB in the fact that these files compress so greatly cause most of it is dead space used to fill the inside of the disc so that the the important data is on the outside (fast accessing) part of the disc, thusly allowing for quicker loads and less CD thrashing.

 

[Skwowwy]

A way to get a better compression in RAR is to select Compression Method to Best and then use a Solid Archive. It has advantages and disadvantages. Read the Help for that.

 

[Majestic_twelve]

Thank you, for the intel.

I just download about 23 more iso's, I am going to have a hell of a time burning the all. hehe I still useing a older liteon 8x4x32 burner.

I will check out that other conversion format you are talking about it sounds interesting since I do alot of game programming myself and I am always looking for the best compression method for distributeing large wav files.