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typedef



Joined: 25 Jul 2010
Posts: 2913
Location: 0x77760000
typedef
If your'e a pirate you'll be familiar with this tool. For those that are not, this tool is a file compressor.

I had always seen it and thought, meh "just another file compressor" until today when I decompressed a 200MB file into files totaling 5GB+.


So I was just curious if anybody has any idea at all what algorithm was used because it's like no other.

If you're interested, here's the GUI version: http://www.klaimsoft.com/winuha/
Post 13 May 2012, 07:39
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17352
Location: In your JS exploiting you and your system
revolution
Is it lossless?
Post 13 May 2012, 09:22
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typedef



Joined: 25 Jul 2010
Posts: 2913
Location: 0x77760000
typedef
revolution wrote:
Is it lossless?

Yes, It's better than any other. Smile
Post 13 May 2012, 09:39
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 7740
Location: Kraków, Poland
Tomasz Grysztar
It really seems to be "just another file compressor". In tests it has compression rations not that much different from 7-zip, while lower efficiency (and UHARC seems to be much worse on text files).
Post 13 May 2012, 09:45
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idle



Joined: 06 Jan 2011
Posts: 359
Location: Ukraine
idle
Thanks.
PAQ intrigued me.
My turn.
I used HTTrack Web Site Copier to create rar-mirror on a file sharing service.
The file is to be deleted soon due to the service limitations, so be quick.
Post 13 May 2012, 13:14
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idle



Joined: 06 Jan 2011
Posts: 359
Location: Ukraine
idle


Last edited by idle on 22 Jun 2012, 15:14; edited 1 time in total
Post 13 May 2012, 13:45
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typedef



Joined: 25 Jul 2010
Posts: 2913
Location: 0x77760000
typedef
Tomasz Grysztar wrote:
It really seems to be "just another file compressor". In tests it has compression rations not that much different from 7-zip, while lower efficiency (and UHARC seems to be much worse on text files).


It is a media file compressor so it uses the dictionary technique. Most pirated digital media files are usually compressed using UHARC. But still I have never seen WinRAR, 7Zip or ZIP do 200MB to 5.75GB or at least I'm yet to. That's just weird.
Post 13 May 2012, 15:35
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idle



Joined: 06 Jan 2011
Posts: 359
Location: Ukraine
idle
typedef wrote:
still I have never seen WinRAR, 7Zip or ZIP do 200MB to 5.75GB

As i know, WinRAR has media-specific options.
Audio/video re-compression depends on a codec used to create those.
Post 13 May 2012, 17:59
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Madis731



Joined: 25 Sep 2003
Posts: 2140
Location: Estonia
Madis731
It boils down to how much time it takes to compress. With UHARC you only see the decompression part (unless you're a pirate yourself). With increased look-ahead lengths anything's possible. I agree that 7-zip doesn't give you the same results with GUI settings (like Compression level: Ultra), but I guess there are ways to craft the command-line 7-zip to get the maximal compression out of it. That is exactly what they (http://www.maximumcompression.com/index.html) have done.
Post 16 May 2012, 10:28
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