Mimic 7Zip compression "Ultra" setting


When compressing with 7Zip, it has the “Ultra” option under the compression setting (when used via command line that would be -mx9)
I do not see an option for the ultra compression when using Aspose.Zip.SevenZip.SevenZipArchive

Am I overlooking something?


There are not such an feature. Aspose.Zip does not resembles 7-zip here. The only option you can set for LZMA2 compression is dictionary size.
If you need such a feature we may consider to provide it.

Yes, this feature should be implemented.
As Aspose contains the Aspose.Zip.SevenZip.SevenZipArchive class to create 7Z files, if it offered the same compressions features like 7-Zip.org, then Aspose’s implementation of 7Zip would be a suitable replacement for using 7-Zip.org.

From my understanding, when I read that Aspose offered the 7Z class it was my impression that it offered the same compression as the freely available 7-Zip.org.

Please read more about that feature here:


Ok, will provide advanced settings for LZMA2 method in some release later.

There is an enhancement: since version 22.8 you can set the number of fast bytes for LZMA2 compression. Find out correspondent SevenZipLZMA2CompressionSettings constructor.


Can you please share an example utilizing this new feature, please?
To mimic the “Ultra” compression as discussed earlier.

Thank you

Hello, there are not exact “ultra” settings as 7-zip has. You can set fastBytes equal to 64 and dictionarySize equal to 64 MB for `SevenZipLZMA2CompressionSettings. This will produce result similar to Ultra settings. However, solid compression and bcj2 filter won’t be applied. Such features may appear in further version.