ntcompress is a tool that creates compressed data in a format that can be handled by the CX library.
% ntcompress <-d8|d16|r|l|h4|h8|lex|lh|lrc> [-s] [-<t|T>[width]] [-H] [-A(4|8|16|32)] [-o outputFile] <inputFile>
% ntcompress -x [-o outputFile] [-s] <inputFile>
Compresses and converts the input file designated by inputFile into a designated format. Run-length compression, LZ77 extended compression, Huffman compression, and difference filter conversion are all possible.
-s option: No messages will be displayed to indicate that compression was successful.
-H option: Because header information is added to the data before it is compressed, the data size will also be appended to the data following expansion.
-A option: Use this to pad the end of the output file with zeros so that the file size is in alignment to the number of bytes specified by the n argument.
-o option: Use this to specify the output file's file name. When nothing is designated, the output file is created with the name (input filename console part)_(compression method).bin.
-t or -T option: Use this to create the output file as a C-format text file.
By adding (1 | 2 | 4) to the option, you can choose between the u8, u16, and u32 types. (The default is u8.)
If u16 or u32 is specified, the file is output as little-endian with the -t option or as big-endian with the -T option.
-x option: Use this to allow the compressed file to be expanded on a PC using ntcompress.
ntcompress.exe also exists as ntcompressD.exe in this program. There is no difference in how the two behave. Normally you should use ntcompress.exe. ntcompressD.exe remains in order to maintain compatibility with past systems.
The following formats can be designated for the compression method:
| Options | Compression Method | Parameters |
|---|---|---|
|
Difference filtering. | Specify the bit size of the comparison unit {8|16}. |
|
Run-length compression. | None. |
|
Huffman compression. | Specify the bit size to encode {4|8}. |
|
LZ77 extended compression (*1). | None. |
|
LZ77 compression (for backward compatibility). | None. |
-lh |
LH format (*2). | None. |
-lrc |
LRC format (*3). | None. |
(*1) You can expect a higher compression ratio with the LZ77 extended compression than with LZ77 compression, but the -l option is preserved for backward compatibility. Either format can be decompressed using the same API, but keep in mind that programs using RVL-SDK 2.4 or earlier cannot expand files compressed in the LZ77 extended format.
The extra processing required for compression/decompression is nearly equal for the LZ extended (-lex) and backward compatible (-l) versions.
(*2) This format is a mix of LZ77 and Huffman compression. Although this depends on the data, you can expect a comparatively high compression ratio. Decompression speed is slower than that obtained with run-length, Huffman, or LZ77 compression. Run-time compression is not supported.
(*3) This format is a mix of LZ77 and RangeCoder compression. Although this depends on the data, you can expect a comparatively high compression ratio. Be aware that it has the slowest decompression speed. Run-time compression is not supported.
$(REVOLUTION_SDK_ROOT)/X86/bin/ntcompress.exe
CXUncompressHuffman
CXUncompressRL
CXUncompressLZ
CXReacUncompHuffman
CXReadUncompRL
CXReadUncompLZ
2009/06/05 Explained the existence of *.exe and *D.exe.
2007/11/01 LH and LRC formats.
2007/04/28 Added LZ77 extended compression.
2006/11/30 Added options for alignment specifications and decompression.
2006/07/06 Initial version.
CONFIDENTIAL