Need help configuring Iso7z/Smart7z to compress large files.

Qriist

New member
Hello, thank you for the product you provide.
I am attempting to use Smart7z to compress a bin/cue cd that I know to have ECM data, and have verified that it is a good dump of the disc.

I have 4gb of RAM available on this PC.

I have had no luck at all setting parameters or even modifying the existing ones. I keep getting the dreaded "The system cannot allocate the required amount of memory" error. I have even tried setting a very low value on the parameters... I'm stumped! Small files compress well enough.

If you could kindly show me what to set, I'd be really happy.

For reference, this is the last test config I tried before I gave up and posted here.:
;::disable wavpack2
::SET %Qriist% LZMA:x1:d12m

;**********************************************************************
;:default: m=%LZMA%
;:default: m=%LZMA%
:default: m=%Qriist%
*.pdf *.rtf
*.iso *.bin *.nrg *.mdf *.img *.pdi *.tar *.cpio *.xpi

I am using 7z 18.05 x64.


PS
Is there a method to call Smart7z on the commandline?
 
Last edited:

Dec

Administrator
Staff member
1) Check that Iso7z is installed (run 7z.exe i - you must see RawSplitter codec in output list).

2) Use the following ini file:

::SET %LZMA2% LZMA2:x9:mt2:d128M
:default: %LZMA2%
:txt: %LZMA2%


3) Select both cue and bin files and сompress them with Smart7z.

Is there a method to call Smart7z on the commandline?
Currently no.
 

Qriist

New member
Thank you for your swift reply. That works.

For a number of reasons, I would prefer to use LZMA over LZMA2 but I still get the allocation error when I modify the above to LZMA. Do you know what could be causing that?
 

Qriist

New member
That did the trick. It's strange to me that there are such allocation issues with LZMA. It's been my experience that LZMA2 takes more RAM than LZMA.
 

keithwalmar

New member
That did the trick. It's strange to me that there are such allocation issues with LZMA. It's been my experience that LZMA2 takes more RAM than LZMA.
LZMA2 is faster for 4-threads, if you compress big file (more than 256 MB), so 7-Zip will be able to split it to blocks.
If the zip file exceeds that size, 7-zip will split it into multiple files automatically, such as integration_serviceLog.zip.001, integration_serviceLog.zip.002, etc. (Way back when, PK Zip used this to span zip files across multiple floppy disks.) You'll need all the files to be present to unzip them. LZMA2 was created for XZ format and it includes changes that are good for that stream compression format. Also LZMA2 is better than LZMA, if you compress already compressed data. LZMA decoder is simple. But PPMd decoder is complex. So now I don’t like the idea of PPMd / LZMA mixing.
 
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