Bug 70190

Summary: replace zip format by an archive format with better compression ratio (7z, tar.xz, ...)
Product: LibreOffice Reporter: Jérôme <jerome.bouat>
Component: filters and storageAssignee: Not Assigned <libreoffice-bugs>
Status: RESOLVED NOTABUG    
Severity: normal    
Priority: medium    
Version: 4.2.0.0.alpha0+ Master   
Hardware: Other   
OS: All   
Whiteboard:
Crash report or crash signature: Regression By:

Description Jérôme 2013-10-06 12:41:33 UTC 
The lzma2 compression method (used by 7z or tar.xz archives formats) provides a better compression ratio than deflate (used by zip).

With the right parameter, lzma2 method can use the same memory for decompression than deflate.

The drawback is a slow compression. However, this could be avoided with multi core/cpu computers which are used nowadays. With recent computers, 1 process can write the uncompressed stream into a pipe. Then an other process read simultaneously the stream from this pipe and compress it with actual parallelism (1 process per cpu).

I think that LibreOffice documents should use 7z format instead of zip.
Comment 1 Urmas 2013-10-06 13:05:13 UTC 
ODF format is using ZIP container with Store/Deflate compression only.
Comment 2 Maxim Monastirsky 2013-10-06 13:08:57 UTC 
(In reply to comment #1)
> ODF format is using ZIP container with Store/Deflate compression only.
Source: http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part3.html#__RefHeading__752791_826425813