Jan B

Thanks for your help all is working fine now.

I double checked it and it was on my end to retrieve the error message from the error code. It failed with a RangeError. To set the dictionary size works for BZip2 and LZMA, but I get an invalid argument error for PPMd. I used the default settings to set the dictionary size of ([CompressionLevel=DictionarySize]1 = 20,3=22,5=24,7=26,9=28 ). I get the same error when I try to set NumFastBytes (WordSize) for PPMd, for all other methods it works fine.

I double checked it and it was on my end to retrieve the error message from the error code. It failed with a RangeError. 1. To set the dictionary size works for BZip2 and LZMA, but I get an invalid argument error for PPMd. I used the default settings to set the dictionary size of ([CompressionLevel=DictionarySize]1 = 20,3=22,5=24,7=26,9=28 ). I get the same error when I try to set NumFastBytes (WordSize) for PPMd, for all other methods it works fine.

I double checked it and it was on my end to retrieve the error message from the error code. It failed with a RangeError. 1. To set the dictionary size works for BZip2 and LZMA, but I get an invalid argument error for PPMd. I used the default settings to set the dictionary size of ([CompressionLevel=DictionarySize]1 = 20,2=22,3=24,4=26,5=28 ). I get the same error when I try to set NumFastBytes (WordSize) for PPMd, for all other methods it works fine.

How should I set the dictionary size in ISetProperties.SetProperties? So far I use as name 'd' and set the dictionary size as a value 15 = 32KB and this as UInt32. The function doesn't fail, but I get an RangeError(HRESULT = 72415980) on compress. I tried also to set the value as Bytes and KBytes, but everytime the compress fails. Without setting this property value the compress works fine.

ok, for my purpose I need it faster. So I tested a bit more and found a solution for me to get this done. I will lower the word size from 32 to 8 and this will speed up Deflate from 14 sec to 10 sec to compress the file with 760858 KB. The file size after compress will be a bit bigger 5 MB, that's really nothing when I see the speed difference.

I did another Test with another file and the test results looks the same. I attach the result, this time only one test round.

I checked it now 3 times in a row and used the windows context menu to compress the files. For the methode Deflate and Deflate64 the file sizes are the same, the other methods has a different size and the size is smaller for the higher compression level. I attach the test results in a text file.