KuaiZip - yet another chinese WinRAR clone

[Surfer]

http://www.kuaizip.com/en/index.html

Proprietary archive file format (KZ), compression ratio increased 5-30%.
Support more than 40 formats.
Friendly and easy interface and detailed wizard for newers.
Multi-volume compression and solid compression.
Encrypt,protect,lock,recover and test compressed archives.
Multi-threaded, multi-level, multi-mode compression.
Powerful self-extracting package.
Add and view compressed archive comments.

Similar to HaoZip, but more powerful.

Interesting, what Eugene and Alexander think about this?

[Matt Mahoney]

The proprietary KZ format is almost certainly LZMA. Compare with 7zip 9.20 using default compression. Shown are size, compression and decompression time and memory used. Windows Task Manager also shows 75% CPU (1.5 of 2 cores on a 2 GHz T3200) for compression and around 35% for decompression for both programs. Both preserve timestamps of original files.

 25,895,909 enwik8.7z
 25,895,915 enwik8.kz
227,905,645 enwik9.7z  1031s  42s  196MB  18MB
227,905,650 enwik9.kz  1061s  47s  197MB  19MB

The license says that it uses WAV compression from WavPack and JPEG compression under GNU license by Przemyslaw Skibinski (I presume PAQ, but no source is included). I didn't test these.

Edit: I confirmed that enwik8.kz and enwik8.7z are identical except for a few bytes at the beginning and end.

[m^2]

JPEG compression under GNU license by Przemyslaw Skibinski (I presume PAQ, but no source is included).

I'd guess it's rejpeg:
http://encode.su/threads/1243-Open-s...highlight=jpeg

[RichSelian]

It's a copycat of lzma. See this page http://www.oschina.net/question/54334_19417

[roytam1]

The latest version of KuaiZip claims that "compressing ultimate-high ZIP files" but it is its own .kz format renamed as .zip instead, the new .kz format contains a RAR archive segment with a "Readme.txt"(in Chinese, translated here) to guide people downloading KuaiZip to decompress that "ZIP" file.

Such technique is ugly, but it is well-known in Chinese software market.