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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<HTML>
+<HEAD>
+ <META http-equiv="Content-Type" content="text/html; charset=Windows-1252">
+ <TITLE>-m (Set compression Method) switch</TITLE>
+ <LINK href="style.css" rel="stylesheet" type="text/css">
+</HEAD>
+
+<BODY>
+
+<H1>-m (Set compression Method) switch</H1>
+
+<P>Specifies the compression method.</P>
+
+<H4>Syntax</H4>
+
+<PRE class="syntax">
+-m&lt;method_parameters>
+
+</PRE>
+
+<P>The format for this switch depends on the archive type.</P>
+
+<UL>
+<LI><TD><A class="parameter" href="#Zip">Zip</A></TD>
+<LI><TD><A class="parameter" href="#GZ">GZip</A></TD>
+<LI><TD><A class="parameter" href="#BZ2">BZip2</A></TD>
+<LI><TD><A class="parameter" href="#7Z">7z</A></TD>
+<LI><TD><A class="parameter" href="#XZ">XZ</A></TD>
+</UL>
+
+<H2><A name="Zip"></A>Zip</H2>
+<TABLE>
+ <TR>
+ <TH width="160">Parameter</TH>
+ <TH align="center">Default</TH>
+ <TH>Description</TH> </TR>
+ <TR>
+ <TD><A class="parameter" href="#ZipX">x=[0 | 1 | 3 | 5 | 7 | 9 ]</A></TD>
+ <TD align="center">5</TD>
+ <TD>Sets level of compression.</TD> </TR>
+ <TR>
+ <TD>m={MethodID}</TD>
+ <TD align="center">Deflate</TD>
+ <TD>Sets a method: Copy, Deflate, Deflate64, BZip2, LZMA, PPMd.</TD> </TR>
+ <TR>
+ <TD><A class="parameter" href="#Deflate_FastBytes">fb={NumFastBytes}</A></TD>
+ <TD align="center">32</TD>
+ <TD>Sets number of Fast Bytes for Deflate encoder.</TD> </TR>
+ <TR>
+ <TD><A class="parameter" href="#Zip_Pass">pass={NumPasses}</A></TD>
+ <TD align="center">1</TD>
+ <TD>Sets number of Passes for Deflate encoder.</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#ZipDictionarySize">d={Size}[b|k|m]</A></TD>
+ <TD align="center">900000</TD>
+ <TD>Sets Dictionary size for BZip2</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#ZipMemorySize">mem={Size}[b|k|m]</A></TD>
+ <TD align="center">24</TD> <TD>Sets size of used memory for PPMd.</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#ZipOrder">o={Size}</A></TD>
+ <TD align="center">8</TD> <TD>Sets model order for PPMd.</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#ZipMultiThread">mt=[off | on | {N}]</A></TD>
+ <TD align="center">on</TD>
+ <TD>Sets multithreading mode.</TD></TR>
+ <TR>
+ <TD>em={EncryptionMethodID}</TD>
+ <TD align="center">ZipCrypto</TD>
+ <TD>Sets a encryption method: ZipCrypto, AES128, AES192, AES256</TD> </TR>
+ <TR> <TD><A class="parameter">tc=[off | on]</A></TD>
+ <TD align="center">off</TD> <TD>Stores NTFS timestamps for files: Modification time, Creation time, Last access time.</TD> </TR>
+ <TR> <TD><A class="parameter">cl=[off | on]</A></TD>
+ <TD align="center">off</TD> <TD>7-Zip always uses local code page for file names.</TD> </TR>
+ <TR> <TD><A class="parameter">cu=[off | on]</A></TD>
+ <TD align="center">off</TD> <TD>7-Zip uses UTF-8 for file names that contain non-ASCII symbols.</TD> </TR>
+</TABLE>
+
+<P>By default (if <B>cl</B> and <B>cu</B> switches are not specified), 7-Zip uses UTF-8 encoding
+only for file names that contain symbols unsupported by local code page.</P>
+
+<DL>
+ <DT><A name="ZipX"></A>x=[0 | 1 | 3 | 5 | 7 | 9 ]</DT>
+ <DD>
+ <P>Sets level of compression. x=0 means Copy mode (no compression).</P>
+ <P>Deflate / Deflate64 settings:</P>
+ <TABLE>
+ <TR> <TH>Level</TH> <TH>NumFastBytes</TH> <TH>NumPasses</TH> <TH>Description</TH> </TR>
+ <TR> <TD class="cc">1</TD> <TD class="cc" rowspan=3>32</TD> <TD class="cc" rowspan=3>1</TD> <TD>Fastest</TD> </TR>
+ <TR> <TD class="cc">3</TD> <TD>Fast</TR>
+ <TR> <TD class="cc">5</TD> <TD>Normal</TR>
+ <TR> <TD class="cc">7</TD> <TD class="cc">64</TD> <TD class="cc">3</TD> <TD>Maximum</TD> </TR>
+ <TR> <TD class="cc">9</TD> <TD class="cc">128</TD> <TD class="cc">10</TD> <TD>Ultra</TD> </TR>
+ </TABLE>
+
+ <P>x=1 and x=3 with Deflate method set fast mode for compression.</P>
+
+ <P>BZip2 settings:</P>
+ <TABLE>
+ <TR> <TH>Level</TH> <TH>Dictionary</TH> <TH>NumPasses</TH> <TH>Description</TH> </TR>
+ <TR> <TD class="cc">1</TD> <TD class="cc">100000</TD> <TD class="cc" rowspan=3>1</TD> <TD>Fastest</TD> </TR>
+ <TR> <TD class="cc">3</TD> <TD class="cc">500000</TD> <TD>Fast</TD> </TR>
+ <TR> <TD class="cc">5</TD> <TD class="cc" rowspan=3>900000</TD> <TD>Normal</TD> </TR>
+ <TR> <TD class="cc">7</TD> <TD align="center">2</TD> <TD>Maximum</TD> </TR>
+ <TR> <TD class="cc">9</TD> <TD align="center">7</TD> <TD>Ultra</TD> </TR>
+ </TABLE>
+ </DD>
+
+ <DT><A name="Deflate_FastBytes"></A>fb={NumFastBytes}</DT>
+ <DD>
+ <P>Sets the number of fast bytes for the Deflate/Deflate64 encoder.
+ It can be in the range from 3 to 258 (257 for Deflate64).
+ Usually, a big number gives a little bit better
+ compression ratio and a slower compression process.
+ A large fast bytes parameter can significantly increase the compression ratio
+ for files which contain long identical sequences of bytes.</P>
+ </DD>
+ <DT><A name="Zip_Pass"></A>pass={NumPasses}</DT>
+ <DD>
+ <P>Sets number of passes for Deflate encoder. It can be in the range from 1 to 15 for Deflate and
+ from 1 to 10 for BZip2. Usually, a big number gives a little bit better
+ compression ratio and a slower compression process.
+ </P>
+ </DD>
+ <DT><A name="ZipDictionarySize"></A>d={Size}[b|k|m]</DT>
+ <DD>
+ <P> Sets the Dictionary size for BZip2. You must specify the size in bytes, kilobytes, or megabytes.
+ The maximum value for the Dictionary size is 900000b. If you do not specify any symbol
+ from set [b|k|m], dictionary size will be calculated as DictionarySize = 2^Size bytes.</P>
+ </DD>
+
+ <DT><A name="ZipMemorySize"></A>mem={Size}[b|k|m]</DT>
+ <DD>
+ <P> Sets the size of memory used for PPMd. You must specify the size in bytes, kilobytes, or megabytes.
+ The maximum value is 256 MB = 2^28 bytes. The default value
+ is 24 (16MB). If you do not specify any symbol from the set [b|k|m], the
+ memory size will be calculated as (2^Size) bytes. PPMd uses the same
+ amount of memory for compression and decompression.</P>
+ </DD>
+
+ <DT><A name="ZipOrder"></A>o={Size}</DT>
+ <DD>
+ <P>Sets the model order for PPMd. The size must be in the range [2,16]. The default value is 8.</P>
+ </DD>
+
+ <DT><A name="ZipMultiThread"></A>mt=[off | on | {N}]</DT>
+ <DD>
+ <P>Sets multithread mode. If you have a multiprocessor or multicore system,
+ you can get a speed increase with
+ this switch. This option affects only compression (with any method) and
+ decompression of BZip2 streams.
+ Each thread in the multithread mode uses 32 MB of RAM for buffering.
+ If you specify {N}, 7-Zip tries to use N threads.</P>
+ </DD>
+</DL>
+
+<H2><A name="GZ"></A>GZip</H2>
+GZip uses the same parameters as Zip, but GZip compresses only with Deflate method.
+So GZip supports only the following parameters: x, fb, pass.
+
+<H2><A name="BZ2"></A>BZip2</H2>
+<TABLE>
+ <TR>
+ <TH width="160">Parameter</TH>
+ <TH align="center">Default</TH>
+ <TH>Description</TH> </TR>
+ <TR>
+ <TD><A class="parameter" href="#BZip2X">x=[1 | 3 | 5 | 7 | 9 ]</A></TD>
+ <TD align="center">5</TD>
+ <TD>Sets level of compression.</TD> </TR>
+ <TR>
+ <TD><A class="parameter" href="#BZip2Pass">pass={NumPasses}</A></TD>
+ <TD align="center">1</TD>
+ <TD>Sets number of Passes for Bzip2 encoder.</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#BZip2DictionarySize">d={Size}[b|k|m]</A></TD>
+ <TD align="center">900000</TD>
+ <TD>Sets Dictionary size for BZip2</TD></TR>
+ <TR>
+ <TD><A class="parameter" href="#BZip2MultiThread">mt=[off | on | {N}]</A></TD>
+ <TD align="center">on</TD>
+ <TD>Sets multithreading mode.</TD></TR>
+</TABLE>
+
+<DL>
+ <DT><A name="BZip2"></A>x=[1 | 3 | 5 | 7 | 9 ]</DT>
+ <DD>
+ <P>Sets level of compression</P>
+ <TABLE>
+ <TR> <TH>Level</TH> <TH>Dictionary</TH> <TH>NumPasses</TH> <TH>Description</TH> </TR>
+ <TR> <TD class="cc">1</TD> <TD class="cc">100000</TD> <TD class="cc" rowspan=3>1</TD> <TD>Fastest</TD> </TR>
+ <TR> <TD class="cc">3</TD> <TD class="cc">500000</TD> <TD>Fast</TD> </TR>
+ <TR> <TD class="cc">5</TD> <TD class="cc" rowspan=3>900000</TD> <TD>Normal</TD> </TR>
+ <TR> <TD class="cc">7</TD> <TD align="center">2</TD> <TD>Maximum</TD> </TR>
+ <TR> <TD class="cc">9</TD> <TD align="center">7</TD> <TD>Ultra</TD> </TR>
+ </TABLE>
+ </DD>
+
+ <DT><A name="BZip2DictionarySize"></A>d={Size}[b|k|m]</DT>
+ <DD>
+ <P> Sets the Dictionary size for BZip2. You must specify the size in bytes, kilobytes, or megabytes.
+ The maximum value for the Dictionary size is 900000b. If you do not specify any symbol
+ from set [b|k|m], dictionary size will be calculated as DictionarySize = 2^Size bytes.</P>
+ </DD>
+
+ <DT><A name="#BZip2Pass"></A>pass={NumPasses}</DT>
+ <DD>
+ <P>Sets the number of passes. It can be in the range from 1 to 10.
+ The default value is 1 for normal mode, 2 for maximum mode and 7 for ultra mode.
+ A bigger number can give a little bit better compression ratio and a slower compression process.
+ </P>
+ </DD>
+ <DT><A name="BZip2MultiThread"></A>mt=[off | on | {N}]</DT>
+ <DD>
+ <P>Sets multithread mode. If you have a multiprocessor or multicore system,
+ you can get a speed increase with
+ this switch. If you specify {N}, for example mt=4, 7-Zip tries to use 4 threads.</P>
+ </DD>
+</DL>
+
+<H2><A name="7Z"></A>7z</H2>
+<TABLE>
+ <TR> <TH width="80">Parameter</TH> <TH align="center">Default</TH> <TH>Description</TH> </TR>
+ <TR> <TD><A class="parameter" href="#SevenZipX">x=[0 | 1 | 3 | 5 | 7 | 9 ]</A></TD>
+ <TD align="center">5</TD><TD>Sets level of compression.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#Solid">s=[off | on | [e] [{N}f] [{N}b | {N}k | {N}m | {N}g]</A></TD>
+ <TD align="center">on</TD> <TD>Sets solid mode.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#Filter">f=[off | on]</A></TD>
+ <TD align="center">on</TD> <TD>Enables or disables compression filters for executable files.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#HeaderCompress">hc=[off | on]</A></TD>
+ <TD align="center">on</TD> <TD>Enables or disables archive header compressing.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#HeaderEncrypt">he=[off | on]</A></TD>
+ <TD align="center">off</TD> <TD>Enables or disables archive header encryption.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#Bind">b{C1}[s{S1}]:{C2}[s{S2}]</A></TD>
+ <TD align="center"> </TD> <TD>Sets binding beetwen coders.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#MethodID">{N}={MethodID}[:param1][:param2][..]</A></TD>
+ <TD align="center">LZMA</TD> <TD>Sets a method: LZMA, LZMA2, PPMd, BZip2, Deflate, Delta, BCJ, BCJ2, Copy.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#MultiThread">mt=[off | on | {N}]</A></TD>
+ <TD align="center">on</TD> <TD>Sets multithreading mode.</TD> </TR>
+ <TR> <TD><A class="parameter">tc=[off | on]</A></TD>
+ <TD align="center">off</TD> <TD>Stores file creation timestamps.</TD> </TR>
+</TABLE>
+
+<DL>
+ <DT><A name="SevenZipX"></A>x=[0 | 1 | 3 | 5 | 7 | 9 ]</DT>
+ <DD>
+ <P>Sets level of compression</P>
+ <TABLE>
+ <TR> <TH>Level</TH> <TH>Method</TH> <TH>Dictionary</TH> <TH>FastBytes</TH> <TH>MatchFinder</TH> <TH>Filter</TH> <TH>Description</TH> </TR>
+ <TR> <TD align="center">0</TD> <TD align="center">Copy</TD> <TD align="center"></TD> <TD align="center"></TD> <TD align="center"></TD> <TD align="center"></TD> <TD>No compression.</TD> </TR>
+ <TR> <TD align="center">1</TD> <TD align="center">LZMA</TD> <TD align="center">64 KB</TD> <TD align="center">32</TD> <TD align="center">HC4</TD> <TD align="center">BCJ</TD> <TD>Fastest compressing</TD> </TR>
+ <TR> <TD align="center">3</TD> <TD align="center">LZMA</TD> <TD align="center">1 MB</TD> <TD align="center">32</TD> <TD align="center">HC4</TD> <TD align="center">BCJ</TD> <TD>Fast compressing</TD> </TR>
+ <TR> <TD align="center">5</TD> <TD align="center">LZMA</TD> <TD align="center">16 MB</TD> <TD align="center">32</TD> <TD align="center">BT4</TD> <TD align="center">BCJ</TD> <TD>Normal compressing</TD> </TR>
+ <TR> <TD align="center">7</TD> <TD align="center">LZMA</TD> <TD align="center">32 MB</TD> <TD align="center">64</TD> <TD align="center">BT4</TD> <TD align="center">BCJ</TD> <TD>Maximum compressing</TD> </TR>
+ <TR> <TD align="center">9</TD> <TD align="center">LZMA</TD> <TD align="center">64 MB</TD> <TD align="center">64</TD> <TD align="center">BT4</TD> <TD align="center">BCJ2</TD><TD>Ultra compressing</TD> </TR>
+ </TABLE>
+ <P>Note: "x" works as "x=9".</P>
+ </DD>
+
+ <DT><A name="Solid"></A>s=[off | on | [e] [{N}f] [{N}b | {N}k | {N}m | {N}g)]</DT>
+ <DD>
+ <P> Enables or disables solid mode. The default mode is s=on.
+ In solid mode, files are grouped together. Usually, compressing in
+ solid mode improves the compression ratio.</P>
+
+ <TABLE>
+ <TR> <TD>e</TD> <TD>Use a separate solid block for each new file extension</TD> </TR>
+ <TR> <TD>{N}f</TD> <TD>Set the limit for number of files in one solid block</TD> </TR>
+ <TR> <TD>{N}b | {N}k | {N}m | {N}g</TD> <TD>Set a limit for the total size of a solid block in bytes</TD> </TR>
+ </TABLE>
+
+ <P>These are the default limits for the solid block size:</P>
+
+ <TABLE>
+ <TR> <TH width="150">Compression Level</TH> <TH>Solid block size</TH> </TR>
+ <TR> <TD>Store</TD> <TD>0 B</TD> </TR>
+ <TR> <TD>Fastest</TD> <TD>16 MB</TD> </TR>
+ <TR> <TD>Fast</TD> <TD>128 MB</TD> </TR>
+ <TR> <TD>Normal</TD> <TD>2 GB</TD> </TR>
+ <TR> <TD>Maximum</TD> <TD>4 GB</TD> </TR>
+ <TR> <TD>Ultra</TD> <TD>4 GB</TD> </TR>
+ </TABLE>
+
+
+ <P>Limitation of the solid block size usually decreases compression ratio but gives the following advantages:</P>
+ <UL>
+ <LI>Decreases losses in case of future archive damage.
+ <LI>Decreases extraction time of a group of files (or just one
+ file), so long as the group doesn't contain the entire archive.</LI></LI>
+ </UL>
+ <P>The updating of solid .7z archives can be slow, since it
+ can require some recompression.</P>
+
+ <P>Example:</P>
+ <PRE class="example">
+ s=100f10m
+ </PRE>
+ <P>set solid mode with 100 files & 10 MB limits per one solid block.</P>
+
+ <DT><A name="Filter"></A>f=[off | on]</DT>
+ <DD>
+ <P>Enables or disables compression filters for executable files:
+ dll, exe, ocx, sfx, sys. It uses BCJ2 filter in Ultra mode and BCJ
+ filter in other modes. The default mode is f=on.
+ </P>
+ <DT><A name="HeaderCompress"></A>hc=[off | on]</DT>
+ <DD>
+ <P> Enables or disables archive header compressing. The default mode is hc=on.
+ If archive header compressing is enabled, some parts of archive header will
+ be compressed with LZMA method.
+ </P>
+ <DT><A name="HeaderEncrypt"></A>he=[off | on]</DT>
+ <DD>
+ <P> Enables or disables archive header encryption. The default mode is he=off.
+ </P>
+ <DT>{N}</DT>
+ <DD>
+ <P>Sets order of methods. It is used also to associate parameters with
+ methods. Numbers must begin from 0. Methods that have smaller numbers will be used
+ before others.</P>
+ </DD>
+
+ <DT><A name="Bind"></A>b{C1}[s{S1}]:{C2}[s{S2}]</DT>
+ <DD>
+ <P> Binds output stream S1 in coder C1 with input stream S2 in coder C2.
+ If stream number is not specified, stream with number 0 will be used.
+ </P>
+ <P> Usally coder has one input stream and
+ one output stream. In 7z some coders can have multiple input and output streams.</P>
+
+ <P>For example, <A class="parameter" href="#BCJ2">BCJ2</A> encoder has one
+ input stream and four output streams.</P>
+ </DD>
+
+ <DT><A name="MultiThread"></A>mt=[off | on | {N}]</DT>
+ <DD>
+ <P>Sets multithread mode. If you have a multiprocessor or multicore system,
+ you can get a increase with this switch.
+ 7-Zip supports multithread mode only for LZMA / LZMA2 compression and
+ BZip2 compression / decompression. If you specify {N}, for example mt=4,
+ 7-Zip tries to use 4 threads. LZMA compression uses only 2 threads.
+ </P>
+ </DD>
+
+ <DT><A name="MethodID"></A>{N}={MethodID}[:param1][:param2] ... [:paramN]</DT>
+ <DD>
+ <P>Sets compression method. You can use any number of methods.
+ The default method is LZMA. </P>
+ <P>Parameters must be in one of the following forms:</P>
+ <UL>
+ <LI>{ParamName}={ParamValue}.
+ <LI>{ParamName}{ParamValue}, if {ParamValue}
+ is number and {ParamName} doesn't contain numbers.
+ </UL>
+
+ <P>Supported methods:</P>
+ <TABLE>
+ <TR> <TH width="60">MethodID</TH> <TH>Description</TH> </TR>
+ <TR> <TD><A class="parameter" href="#LZMA">LZMA</A></TD> <TD>LZ-based algorithm</TD> </TR>
+ <TR> <TD><A class="parameter" href="#LZMA2">LZMA2</A></TD> <TD>LZMA-based algorithm</TD> </TR>
+ <TR> <TD><A class="parameter" href="#PPMd">PPMd</A></TD> <TD>Dmitry Shkarin's PPMdH with small changes</TD> </TR>
+ <TR> <TD>BZip2</TD> <TD>BWT algorithm</TD> </TR>
+ <TR> <TD>Deflate</TD> <TD>LZ+Huffman</TD> </TR>
+ <TR> <TD>Copy</TD> <TD>No compression</TD> </TR>
+ </TABLE>
+
+ <P>Supported filters:</P>
+ <TABLE>
+ <TR> <TH width="60">MethodID</TH> <TH>Description</TH> </TR>
+ <TR> <TD><A class="parameter" href="#Delta">Delta</A></TD> <TD>Delta filter</TD> </TR>
+ <TR> <TD>BCJ</TD> <TD>converter for x86 executables</TD> </TR>
+ <TR> <TD><A class="parameter" href="#BCJ2">BCJ2</A></TD> <TD>converter for x86 executables (version 2)</TD> </TR>
+ <TR> <TD>ARM</TD> <TD>converter for ARM (little endian) executables</TD> </TR>
+ <TR> <TD>ARMT</TD> <TD>converter for ARM Thumb (little endian) executables</TD> </TR>
+ <TR> <TD>IA64</TD> <TD>converter for IA-64 executables</TD> </TR>
+ <TR> <TD>PPC</TD> <TD>converter for PowerPC (big endian) executables</TD> </TR>
+ <TR> <TD>SPARC</TD> <TD>converter for SPARC executables</TD> </TR>
+ </TABLE>
+ <P>Filters increase the compression ratio for some types of files. Filters
+ must be used with one of the compression method (for example, BCJ + LZMA).</P>
+ </DD>
+
+ <H4><A name="LZMA"></A>LZMA</H4>
+ <P> LZMA is an algorithm based on Lempel-Ziv algorithm.
+ It provides very fast decompression (about 10-20 times faster than compression).
+ Memory requirements for compression and decompression also are different (see
+ <A class="parameter" href="#DictionarySize">d={Size}[b|k|m]</A> switch for details).</P>
+
+ <TABLE>
+ <TR> <TH width="80">Parameter</TH> <TH align="center">Default</TH> <TH>Description</TH> </TR>
+
+ <TR> <TD><A class="parameter" href="#LZMAMode">a=[0|1]</A></TD>
+ <TD align="center">1</TD> <TD>Sets compressing mode</TD> </TR>
+ <TR> <TD><A class="parameter" href="#DictionarySize">d={Size}[b|k|m]</A></TD>
+ <TD align="center">24</TD> <TD>Sets Dictionary size</TD> </TR>
+ <TR> <TD><A class="parameter" href="#MatchFinder">mf={MF_ID}</A></TD>
+ <TD align="center">bt4</TD> <TD>Sets Match Finder</TD> </TR>
+ <TR> <TD><A class="parameter" href="#FastBytes">fb={N}</A></TD>
+ <TD align="center">32</TD> <TD>Sets number of Fast Bytes</TD></TR>
+ <TR> <TD><A class="parameter" href="#MatchFinderCycles">mc={N}</A></TD>
+ <TD align="center">32</TD><TD>Sets Number of Cycles for Match Finder</TD> </TR>
+ <TR> <TD><A class="parameter" href="#LitContext">lc={N}</A></TD>
+ <TD align="center">3</TD> <TD>Sets number of Literal Context bits - [0, 8]</TD></TR>
+ <TR> <TD><A class="parameter" href="#LitPos">lp={N}</A></TD>
+ <TD align="center">0</TD> <TD>Sets number of Literal Pos bits - [0, 4]</TD></TR>
+ <TR> <TD><A class="parameter" href="#PosBits">pb={N}</A></TD>
+ <TD align="center">2</TD> <TD>Set number of Pos Bits - [0, 4]</TD></TR>
+ </TABLE>
+
+
+ <DL>
+ <DT><A name="#LZMAMode"></A>a=[0|1]</DT>
+ <DD>
+ <P> Sets compression mode: 0 = fast, 1 = normal.
+ Default value is 1.</P>
+ </DD>
+ <DT><A name="DictionarySize"></A>d={Size}[b|k|m]</DT>
+ <DD>
+ <P> Sets Dictionary size for LZMA. You must specify the size in bytes, kilobytes, or megabytes.
+ The maximum value for dictionary size is 1 GB = 2^30 bytes. Default values for LZMA
+ are 24 (16 MB) in normal mode, 25 (32 MB) in maximum mode (-mx=7)
+ and 26 (64 MB) in ultra mode (-mx=9).
+ If you do not specify any symbol from the set [b|k|m], the
+ dictionary size will be calculated as DictionarySize = 2^Size bytes.
+ For decompressing a file compressed by LZMA method with dictionary size N, you need
+ about N bytes of memory (RAM) available.
+ </P>
+ </DD>
+ <DT><A name="MatchFinder"></A>mf={MF_ID}</DT>
+ <DD>
+ <P> Sets Match Finder for LZMA. Default method is bt4.
+ Algorithms from hc* group don't provide a good compression ratio,
+ but they often work pretty fast in combination with fast mode (a=0).
+ Memory requirements depend on dictionary size (parameter "d" in table below).
+ </P>
+ <TABLE>
+ <TR> <TH>MF_ID</TH> <TH class="cc">Dictionary</TH> <TH class="cc" colspan = 2>Memory Usage</TH> <TH class="cc" colspan = 2>Description</TH> </TR>
+ <TR> <TD class="cc">bt2</TD> <TD></TD> <TD align="right"> 9.5 * d</TD> <TD class="cc" rowspan=6> + 4 MB</TD> <TD class="cc" rowspan=4>Binary Tree</TD> <TD>2 bytes hashing</TD> </TR>
+ <TR> <TD class="cc">bt3</TD> <TD></TD> <TD align="right">11.5 * d</TD> <TD>3 bytes hashing</TD> </TR>
+ <TR> <TD class="cc" rowspan=2>bt4</TD> <TD class="cc">64 KB ... 48 MB</TD> <TD align="right">11.5 * d</TD> <TD class="cc" rowspan=6>4 bytes hashing</TD> </TR>
+ <TR> <TD class="cc">64 MB ... 1024 MB</TD> <TD align="right">10.5 * d</TD> </TR>
+ <TR> <TD class="cc" rowspan=2>hc4</TD> <TD class="cc">64 KB ... 48 MB</TD> <TD align="right"> 7.5 * d</TD> <TD class="cc" rowspan=2>Hash Chain </TD></TR>
+ <TR> <TD class="cc">64 MB ... 1024 MB</TD> <TD align="right"> 6.5 * d</TD> </TR>
+ </TABLE>
+ <P>Note: Your operation system also needs some amount of physical memory for internal purposes.
+ So keep at least 32MB of physical memory unused.</P>
+ </DD>
+
+ <DT><A name="FastBytes"></A>fb={N}</DT>
+ <DD>
+ <P>Sets number of fast bytes for LZMA. It can be in the range from 5 to 273.
+ The default value is 32 for normal mode and 64 for maximum and ultra modes.
+ Usually, a big number gives a little bit better
+ compression ratio and slower compression process.
+ </P>
+ </DD>
+ <DT><A name="MatchFinderCycles"></A>mc={N}</DT>
+ <DD>
+ <P>Sets number of cycles (passes) for match finder. It can be in range from 0 to 1000000000.
+ Default value is (16 + number_of_fast_bytes / 2) for BT* match finders and
+ (8 + number_of_fast_bytes / 4) for HC4 match finder.
+ If you specify mc=0, LZMA will use default value.
+ Usually, a big number gives a little bit better compression ratio and slower
+ compression process. For example, mf=HC4 and mc=10000 can provide almost the same
+ compression ratio as mf=BT4.</P>
+ </DD>
+ <DT><A name="LitContext"></A>lc={N}</DT>
+ <DD>
+ <P>Sets the number of literal context bits (high bits of previous literal).
+ It can be in range from 0 to 8.
+ Default value is 3. Sometimes lc=4 gives gain for big files.</P>
+ </DD>
+ <DT><A name="LitPos"></A>lp={N}</DT>
+ <DD>
+ <P>Sets the number of literal pos bits (low bits of current position for literals).
+ It can be in the range from 0 to 4.
+ The default value is 0. The lp switch is intended for periodical data when the
+ period is equal to 2^value (where lp=value). For example, for 32-bit (4 bytes)
+ periodical data you can use lp=2. Often it's better to set lc=0,
+ if you change lp switch.</P>
+ </DD>
+ <DT><A name="PosBits"></A>pb={N}</DT>
+ <DD>
+ <P>Sets the number of pos bits (low bits of current position).
+ It can be in the range from 0 to 4.
+ The default value is 2. The pb switch is intended for periodical data when the
+ period is equal 2^value (where lp=value). </P>
+ </DD>
+
+ </DL>
+
+ <H4><A name="LZMA2"></A>LZMA2</H4>
+ <P>LZMA2 is modified version of LZMA. it provides the following advantages over LZMA:</P>
+ <UL>
+ <LI>Better compression ratio for data than can't be compressed. LZMA2 can store such
+ blocks of data in uncompressed form. Also it decompresses such data faster.
+ <LI>Better multithreading support. If you compress big file, LZMA2 can split
+ that file to chunks and compress these chunks in multiple threads.
+ </UL>
+
+ <TABLE>
+ <TR> <TH width="80">Parameter</TH> <TH align="center">Default</TH> <TH>Description</TH> </TR>
+
+ <TR> <TD><A class="parameter" href="#ChunkSize">c={Size}[b|k|m]</A></TD>
+ <TD align="center">dictSize * 4</TD> <TD>Sets Chunk size</TD> </TR>
+ </TABLE>
+
+ <P>If you don't specify ChunkSize, LZMA2 sets it to DictionarySize * 4.</P>
+
+ <P>LZMA2 also supports all LZMA parameters, but lp+lc cannot be larger than 4.</P>
+
+ <P>LZMA2 uses: 1 thread for each chunk in x1 and x3 modes; and
+ 2 threads for each chunk in x5, x7 and x9 modes.
+ If LZMA2 is set to use only such number of threads required for one chunk,
+ it doesn't split stream to chunks. So you can get different compression
+ ratio for different number of threads. You can get the best compression
+ ratio, when you use 1 or 2 threads.</P>
+
+ <H4><A name="PPMd"></A>PPMd</H4>
+ <P> PPMd is a PPM-based algorithm. This algorithm is mostly based
+ on Dmitry Shkarin's PPMdH source code. PPMd provides very good compression ratio for
+ plain text files. There is no difference between compression speed and
+ decompression speed. Memory requirements for compression and decompression
+ also are the same.</P>
+ <TABLE>
+ <TR> <TH width="80">Parameter</TH> <TH align="center">Default</TH> <TH>Description</TH> </TR>
+ <TR> <TD><A class="parameter" href="#MemorySize">mem={Size}[b|k|m]</A></TD>
+ <TD align="center">24</TD> <TD>Sets size of used memory for PPMd.</TD> </TR>
+ <TR> <TD><A class="parameter" href="#Order">o={Size}</A></TD>
+ <TD align="center">6</TD> <TD>Sets model order for PPMd.</TD> </TR>
+ </TABLE>
+ <DL>
+ <DT><A name="MemorySize"></A>mem={Size}[b|k|m]</DT>
+ <DD>
+ <P> Sets the size of memory used for PPMd. You must specify the size in bytes, kilobytes, or megabytes.
+ The maximum value is 2GB = 2^31 bytes. The default value
+ is 24 (16MB). If you do not specify any symbol from the set [b|k|m], the
+ memory size will be calculated as (2^Size) bytes. PPMd uses the same
+ amount of memory for compression and decompression.</P>
+ </DD>
+
+ <DT><A name="Order"></A>o={Size}</DT>
+ <DD>
+ <P>Sets the model order for PPMd. The size must be in the range [2,32]. The default value is 6.</P>
+ </DD>
+ </DL>
+
+ <H4><A name="BCJ2"></A>BCJ2</H4>
+ <P>BCJ2 is a Branch converter for 32-bit x86 executables (version 2).
+ It converts some branch instructions for increasing further compression.</P>
+ <P>A BCJ2 encoder has one input stream and four output streams:</P>
+ <UL>
+ <LI>s0: main stream. It requires further compression.</LI>
+ <LI>s1: stream for converted CALL values. It requires further compression.</LI>
+ <LI>s2: stream for converted JUMP values. It requires further compression.</LI>
+ <LI>s3: service stream. It is already compressed.</LI>
+ </UL>
+ <P>If LZMA is used, the size of the dictionary for streams
+ s1 and s2 can be much smaller (512 KB is enough for most cases)
+ than the dictionary size for stream s0.</P>
+
+ <H4><A name="Delta"></A>Delta</H4>
+ <P>It's possible to set delta offset in bytes. For example, to compress 16-bit stereo
+ WAV files, you can set "0=Delta:4". Default delta offset is 1.</P>
+</DL>
+
+<H2><A name="XZ"></A>XZ</H2>
+XZ supports only LZMA2 codec now. The switches are similar to switches for 7z format.
+
+<H4>Examples</H4>
+
+<PRE class="example">
+7z a -tzip archive.zip *.jpg -mx0
+</PRE>
+
+<P>adds <SPAN class="filename">*.jpg</SPAN> files to
+ <SPAN class="filename">archive.zip</SPAN> archive without compression.</P>
+
+<PRE class="example">
+7z a -t7z archive.7z *.exe *.dll -m0=BCJ -m1=LZMA:d=21 -ms -mmt
+</PRE>
+
+<P>adds <SPAN class="filename">*.exe</SPAN> and <SPAN class="filename">*.dll</SPAN>
+files to solid archive <SPAN class="filename">archive.7z</SPAN> using LZMA method with
+2 MB dictionary and BCJ converter. Compression will use multithreading optimization.</P>
+
+<PRE class="example">
+7z a -t7z archive.7z *.exe *.dll -m0=BCJ2 -m1=LZMA:d23 -m2=LZMA:d19 -m3=LZMA:d19
+ -mb0:1 -mb0s1:2 -mb0s2:3
+</PRE>
+
+<P>adds <SPAN class="filename">*.exe</SPAN> and <SPAN class="filename">*.dll</SPAN>
+ files to archive <SPAN class="filename">archive.7z</SPAN> using BCJ2 converter,
+ LZMA with 8 MB dictionary for main output stream (s0),
+ and LZMA with 512 KB dictionary for s1 and s2 output streams of BCJ2.</P>
+
+
+<PRE class="example">
+7z a -t7z archive.7z *.txt -m0=PPMd
+</PRE>
+
+<P>adds <SPAN class="filename">*.txt</SPAN> files to archive
+<SPAN class="filename">archive.7z</SPAN> using PPMd method.</P>
+
+
+
+
+<H4>Commands that can be used with this switch</H4>
+
+<P>
+ <A href="../commands/add.htm">a (Add)</A>,
+ <A href="../commands/delete.htm">d (Delete)</A>,
+ <A href="../commands/update.htm">u (Update)</A>,
+</P>
+
+<H4>See also</H4>
+
+<P>
+ <B>Switches:</B>
+ <A href="type.htm">-t (set Type of archive)</A>,
+</P>
+
+</BODY>
+</HTML>
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