MPRESS - a UPX alternative

[tproli]

Just found a small command-line utility called MPRESS to compress exe and dll files (just like UPX). I know nowadays size is not really a big issue but personally I like to get rid of any extra bit if I can.

Webpage:
http://www.matcode.com/

The MPRESS subpage is apparently down atm.

I've made some quick tests to see if it does a better job than UPX. I have to say it's pretty good but can't say it's better than UPX. Sometimes it fails to compress and sometimes creates larger files than UPX, but in some cases the resulting file is much smaller. Compressing one of the dlls of AIMP2 made AIMP2 unusable though. The lack of decompression is also a negative issue.

Some positive examples:

Code: Select all

PDFXCview.exe
9,6 MB -> 3,6 MB (upx: 4 MB)

k-mac
0,98 MB -> 453 KB (upx: 482 KB)

PicPick
4,5 MB -> 1,2 MB (upx: 1,3 MB)

opera.dll
11,6 MB -> 4,5 MB (upx: 5,3 MB)

As you can see in some cases it is worth trying. I've tested it on XP SP2 and I haven't got any antivirus alert (using ESET Smart Security).

[guinness]

This is the alternative compression used in ArcThemALL! too.

[JohnTHaller]

It should be noted that GPLed binaries compressed with MPRESS can not be redistributed. The inability to decompress is an issue. I also thought I'd read that it slows apps down startup-wise compared to UPX (UPX in general is only a 1% difference or less).

[guinness]

It should be noted that GPLed binaries compressed with MPRESS can not be redistributed. The inability to decompress is an issue. I also thought I'd read that it slows apps down startup-wise compared to UPX (UPX in general is only a 1% difference or less).

I didn't know that. I take it that apps compressed with UPX can be redistributed of course! Thanks for the warning.

[JohnTHaller]

I didn't know that. I take it that apps compressed with UPX can be redistributed of course! Thanks for the warning.

Correct. UPX is open source (under the GPL) and has exceptions for the license built in allowing you to use it with software under any license you're allowed to distribute it as. That's why we use it for PortableApps.com releases and why it's built in to the PortableApps.com AppCompactor. I could include MPRESS as an option in the AppCompactor, but as it doesn't really add anything over UPX, has licensing issues with redistribution and appears to have some technical limitations, I figured that it would just make it more complicated. Plus, we've used UPX for 6 years for PortableApps.com, so we're pretty happy with it.

[carbonize]

That and some anti virus software has a nasty habit of flagging compressed executables as viruses due to bad heuristics.

[JohnTHaller]

That and some anti virus software has a nasty habit of flagging compressed executables as viruses due to bad heuristics.

Quite true. This happens far less with UPX these days, though. The popularity of PortableApps.com has helped a bit; having millions of users out there to complain about false positives is a good reason for them to fix their definitions quickly. We're actually getting into two major A/V firms' whitelists as a result.

[m^(2)]

(UPX in general is only a 1% difference or less).

This is untrue. The real answer is 'depends, but usually much more'. I did some tests, you can find it somewhere on portablefreeware.