How to uncompress WinZip 12+ JPEG method?

[LigH]

Is an installation of WinZip (at least as test version) mandatory to unpack a ZIP archive which contains JPEG images compressed with the proprietary "lossless JPEG compression" method, or do you know any other freeware tools which support it for unpacking?

7-zip does not belong to them, but at least it identifies the method as "Jpeg".

[raffriff42]

PeaZip? http://peazip.sourceforge.net/

[LigH]

No: "Unsupported method".

[LoRd_MuldeR]

Maybe this might be of interest:
http://code.google.com/p/theunarchiver/wiki/WinZipJpegErrata

This explains why most Freeware/OpenSource tools do not support this compression method: The specs apparently are a mess!

It also indicates that The Unarchiver (apparently for MacOS only) should support it - more or less.

[LigH]

Bad news then; I don't have a Mac, and I won't buy one just to unpack this ZIP. :p

So I probably will have to install WinZip.

[the_weirdo]

The Download section of The Unarchiver project (that LoRd_MuldeR mentions) also includes command-line ultilities for Windows, but I don't know if they can unpack your ZIP.

[LoRd_MuldeR]

Looks like unar (not "unrar") is supposed to provide the same functionality as The Unarchiver, just as a command-line program:
http://unarchiver.c3.cx/commandline

And it does have a Windows version as well as a Linux version (available from Ubuntu repositories). This might indeed by the solution...

[LigH]

Well, I found a copy of WinZip 12 (which was not yet too bloated, compared to the current v18). Interesting method (also known as "Zipx"), had a compression of ~80% for JPEGs. But IMHO, not worth the "forced customer relation".

Regarding documented supported formats (http://unarchiver.c3.cx/formats), unar may have been a solution. I'll keep that one in case another archive may arrive some day.