While making a Xpress Huffman compressor (for the Windows 8 bootmgr) I did a lot of research on different Microsoft compression formats. I have summarized my findings in the table below. If you have anything to add to or correct in the table below please tell me!

I plan to release source code for LZNT1, LZX, Xpress (Lz), and Xpress Huffman compression and decompression. My goal is to have faster and/or better compressors than the Microsoft provided ones.

I created a custom library to extract compressed files from a WIM file that did not require the Microsoft WIM library. Using the Microsoft WIM Library, to extract a single file is actually quite an elaborate process. I predicted this would greatly speed up the start up and running of my Windows 7 Boot Updater program since I use that file whenever the animation is set to "Default".

My current method (in Alpha v9) is to:

For the last couple of days I have been playing with WIM compression. I wanted to be able to directly read a given file from a WIM, even if that WIM is embedded in a DLL resource (specifically the activity.bmp file in the WIM in bootres.dll). I predicted this would greatly speed up the start up and running of my Windows 7 Boot Updater program since I use that file whenever the animation is set to "Default", see an entry on that for more information about its success.

WIM files support 2 types of compression and also support not being compressed.…