X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=doc%2Fimagex-capture.1.in;h=6d995f5b184779a22ac600a3fa6b6e7734faee3f;hp=410546674e53b648777414cc6c38c64fff2b9f18;hb=5ab0691733e0724ba5cd73bd4f9c0963cfe1d276;hpb=d92446abf69f8a9eff9aed1123f37122647cc7e0 diff --git a/doc/imagex-capture.1.in b/doc/imagex-capture.1.in index 41054667..6d995f5b 100644 --- a/doc/imagex-capture.1.in +++ b/doc/imagex-capture.1.in @@ -202,18 +202,23 @@ compression ratio. This currently only has an effect for LZX ("maximum", the default) and LZMS ("recovery") compression. .TP \fB--chunk-size\fR=\fISIZE\fR -Set the WIM compression chunk size to \fISIZE\fR. Using this option is not -recommended because WIM chunk sizes other than the default of 32768 have varying -levels of compatibility with Microsoft's software (depending on the compression -type, chunk size, and software version). In addition, wimlib versions before -1.6.0 do not support alternate chunk sizes. But if you decide to use this -option regardless, you can choose a chunk size that is a power of 2 greater than -or equal to 2^15 (32768) up to a maximum determined by the compression format. -Larger chunks mean larger LZ77 dictionaries and better compression ratios on -sufficiently large files, but slower random access. For LZX ("maximum") -compression, the maximum allowed chunk size is 2^21 (2097152), and for XPRESS -("fast") and LZMS ("recovery") compression, the maximum allowed chunk size is -2^26 (67108644). +Set the WIM compression chunk size to \fISIZE\fR. Larger chunks mean larger +LZ77 dictionaries and better compression ratios on sufficiently large files, but +slower random access. \fBUsing this option is generally not recommended because +of the compatibility limitations detailed in the next paragraph.\fR But if you +decide to use this option regardless, you may choose a chunk size that is a +power of 2 greater than or equal to 2^15 (32768) up to a maximum determined by +the compression format. For LZX ("maximum") compression, the maximum allowed +chunk size is 2^21 (2097152), and for XPRESS ("fast") and LZMS ("recovery") +compression, the maximum allowed chunk size is 2^26 (67108864). +.IP "" +For XPRESS and LZX compression, Microsoft's implementation (as of Windows 8) +does not appear to support alternate chunk sizes; although it will still open +such files, it will crash, extract the data incorrectly, or report that the data +is invalid. For LZMS compression, Micrososft's implementation (as of Windows 8) +appears to only support chunk sizes that are powers of 2 between 2^15 (32768) +and 2^20 (1048576) inclusively. In addition, wimlib versions before 1.6.0 do +not support alternate chunk sizes. .TP \fB--pack-streams\fR, \fB--solid\fR Create a "solid" archive that compresses multiple unique streams ("files")