Versions tested: 13.0
Optimal parameters: -
Authors: Igor Pavlov, Dmitry Shkarin, Allume Systems
Notable peformances: -


the program website March 28, 2009


The program help describes the compression methods:

Compression Method

Unlike other formats, StuffItX supports a number of different compression methods. In general, each compression method is optimized for particular types of data. The default setting uses a method that attempts to pick the best compressor for each file type you add to the archive, and is recommended for general use. The following compression methods are included:


In the matching algorithms (Method 1 & 2 above), levels 1-9 generally correspond to Gzip's compression levels. The higher the number the harder it tries to find a match (more compression, but slower). Levels above 9 use a different, more exhaustive search for previous matches, which gets extra compression, but at the expense of speed. In the prediction algorithm, the level corresponds to how many previous bytes to use when making the prediction.


File Recompression

The StuffItX file format includes recompressors for making files even smaller. Like the JPEG compression we introduced in 2005 and the Zip recompression introduced in StuffIt 11, these recompressors make files smaller by 'disassembling' the structure of the data type and compressing it more efficienly using the StuffItX format's own compressors. When the item is expanded from the StuffItX archive, the structure for that particular data type is reassembled. Generally this results in output that is identical to the original, but in some instances the output may not be 100% identical. The content itself, and any ancillary data is never lost - just the bit encoding changes sometimes.

A good illustration of this concept is Zip recompression. There are many compression attributes that can be used to create a Zip archive. When recompressing a Zip into a SITx archive, the Zip is opened and its content is compressed into the SITx archive. Upon expansion, the Zip archive is recreated. The recreated Zip archive and the original Zip archive may have different compression attributes and are therefore not identical, but if each of the Zips is expanded the resulting output will be identical.

This same idea also applies to image formats that contain compressed information as part of their structure. When the file structure is not identical, but the content is, it is commonly referred to as "pixel-perfect". Identical output is commonly referred to as "bit-perfect".

StuffIt includes custom recompressors for these file formats:

version 13.0 help pages


The documentation for command line switches is unclear for version 13.0, so the following information was provided by "Skymmer":

My own draft notes for StuffIt:

(Have info that should be added here? E-mail.)

9.0 disqualified: no command line interface (despite the manual mentioning it).

13.0 disqualified. The program is not movable, after uninstallation, it gives the following message: 'Failed! This application has failed to start because the application configuration is in correct. Reinstalling the application may fix this problem.'

13.0 cannot create archives from multiple files using '/c': 'Unable to archive files - engine error: OS error - The filename, directory name, or volume label syntax is incorrect.- error code is 123'. Using '/a' the program simply crashes. Therefore TAR must be used.

13.0 SFX option creates 2 files, an exe and an archive. The exe (GUI) requires user interaction.

13.0 decompression needs the following files: 'console_stuffEN.exe, EngineShell.dll, foundation.dll, pthreadVCE.dll, StuffItEngine.dll, Plugins/sitx.dll'.

Warning: once the 13.0 GUI is executed, it launches a heavy background process CmdLine.Exe that can be only stopped using alt+ctrl+del.

Disqualified (why) configurations (with qualification ratings)
Ver Rating CPR DPR S.E. R.E. Ratio C. kB/s D. kB/s
-m=1 -l=1 -x=15
13.0 program is not movable (q1)
-m=1 -l=15 -x=15
13.0 program is not movable (q1)
-m=2 -l=1 -x=26
13.0 program is not movable (q1)
-m=2 -l=5 -x=26
13.0 program is not movable (q1)
-m=8 -l=3 -x=23
13.0 program is not movable (q1)

Version info

13.0, tar: yes, mode: n/a, crc32: n/a, decoder: n/a
compression: console_stuffen.exe /c <args> -a=<cfile> <src>
decompression: console_stuffen.exe /x <cfile>