7.9 KiB
7-Zip external method IDs, that are not included to 7-Zip
History of this document
Overview of defined ID ranges
ID | Codec, Author | 7-Zip Plugin Author ---------+------------------------------+---------------------- F7 0x xx | reserved | F7 10 xx | LZHAM, Rich Geldreich | Rich Geldreich F7 11 01 | ZStandard, Yann Collet | Tino Reichardt F7 11 02 | Brotli, Google | Tino Reichardt F7 11 04 | LZ4, Yann Collet | Tino Reichardt F7 11 05 | LZ5, Przemyslaw Skibinski | Tino Reichardt F7 11 06 | Lizard, Przemyslaw Skibinski | Tino Reichardt
Range F7 10 xx - LZHAM
Description: Lossless is a data compression codec with LZMA-like ratios but 1.5x-8x faster decompression speed.
License: LZHAM library is provided as open source software using the MIT license.
7-Zip Container Header: Byte _ver; Byte _dict_size; Byte _level; Byte _flags; Byte _reserved[1];
Algorithm author: Rich Geldreich
- Homepage: https://github.com/richgel999/lzham_codec
- Source: https://github.com/richgel999/lzham_codec
Codec plugin author: Rich Geldreich
- Homepage: http://richg42.blogspot.com/2015/11/lzham-custom-codec-plugin-for-7-zip.html
- Source: https://github.com/richgel999/lzham_codec_devel
Range F7 11 01, ZStandard
Description: Zstandard is a real-time compression algorithm, providing high compression ratios. It offers a very wide range of compression / speed trade-off, while being backed by a very fast decoder.
License: Zstandard library is provided as open source software using the BSD license.
7-Zip Container Header: Byte _ver_major; // currently 1 Byte _ver_minor; // currently 1 Byte _level; // currently 1..22 Byte _reserved[2];
- this header holds some information about the version, which was used for creating that 7-Zip container data
- _ver_major should contain the major release of zstd
- _ver_minor should contain the major release of zstd
- _level should contain the level, the data is packed with
- the other two bytes should be set to zero currently and are reserved for future use
Algorithm author: Yann Collet
- Homepage: https://facebook.github.io/zstd/
- Source: https://github.com/facebook/zstd
Codec plugin author: Tino Reichardt
- Homepage: https://mcmilk.de/projects/7-Zip-zstd/
- Source: https://github.com/mcmilk/7-Zip-zstd
Modes:
- threading is supported through skippable frame id 0x184D2A50U
- all levels are supported (1..22)
- future versions of zstd will support multithreading out of the box
- this new format is fully compatible with the one within this codec
- the codec is used as archiv handler also, see ZstdHandler.cpp
- this handler is does not use any additional headers, it supports the plain zstd v1.0 format
- when compiled with ZSTD_LEGACY_SUPPORT, then support is increased to these addtional version numbers of zstd: v0.1 up v0.7
- future formats of this algorithm will be fully compatible with release v1.0 of ZStandard (ZStandard 0.8 == ZStandard 1.0)
- one ID should be okay for this codec
Versions: The 7-Zip codec will be kept in sync with the current releases of ZStandard.
Range F7 11 02, Brotli
Description: Brotli is a generic-purpose lossless compression algorithm that compresses data using a combination of a modern variant of the LZ77 algorithm, Huffman coding and 2nd order context modeling, with a compression ratio comparable to the best currently available general-purpose compression methods. It is similar in speed with deflate but offers more dense compression.
License: The Brotli library is provided as open source software using the MIT license.
7-Zip Container Header (3 bytes): Byte _ver_major; // currently 0 Byte _ver_minor; // currently 6 Byte _level; // currently 1..11 (Brotli quality)
- this header holds some information about the version, which was used for creating that 7-Zip container data
- _ver_major should contain the major release of brotli
- _ver_minor should contain the major release of brotli
- _level should contain the level, the data is packed with
Algorithm author: Google Staff
- Homepage: https://brotli.org/
- Source: https://github.com/google/brotli
Codec plugin author: Tino Reichardt
- Homepage: https://mcmilk.de/projects/7-Zip-zstd/
- Source: https://github.com/mcmilk/7-Zip-zstd
Modes:
- threading is supported through skippable frame id 0x184D2A50U
- all levels are supported (1..11)
- one ID should be okay for this codec
Versions: The 7-Zip codec will be kept in sync with the current releases of Brotli.
Range F7 11 04, LZ4
Description: LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core (0.16 Bytes/cycle). It features an extremely fast decoder, with speed in multiple GB/s per core (0.71 Bytes/cycle). A high compression derivative, called LZ4_HC, is available, trading customizable CPU time for compression ratio.
License: LZ4 library is provided as open source software using the BSD license.
7-Zip Container Header: Byte _ver_major; // currently 1 Byte _ver_minor; // currently 7 Byte _level; // 1..12 Byte _reserved[2];
- this header holds some information about the version, which was used for creating that 7-Zip container data
- _ver_major should contain the major release of LZ4
- _ver_minor should contain the major release of LZ4
- _level should contain the level, the data is packed with
- the other two bytes should be set to zero currently and are reserved for future use
Algorithm author: Yann Collet
- Homepage: https://lz4.github.io/lz4/
- Source: https://github.com/lz4/lz4
Codec plugin author: Tino Reichardt
- Homepage: https://mcmilk.de/projects/7-Zip-zstd/
- Source: https://github.com/mcmilk/7-Zip-zstd
Modes:
- threading is supported through skippable frame id 0x184D2A50U
- all levels of LZ4 v1.7.4 are supported (1..16)
- the codec is used as archiv handler also, see Lz4Handler.cpp
- this handler is does not use any additional headers
- it supports the plain LZ4 v1.7.4 format (this covers all current lz4 implemetations)
- future formats of this algorithm should be fully compatible with current release
- one ID should be okay for this codec
Versions: The 7-Zip codec will be kept in sync with the current releases of LZ4.
Range F7 11 05, LZ5
Description: LZ5 is a modification of LZ4 which gives a better ratio at cost of slower compression and decompression.
License: LZ5 library is provided as open source software using the BSD license.
7-Zip Container Header: Byte _ver_major; // currently 1 Byte _ver_minor; // currently 5 Byte _level; // 1..15 Byte _reserved[2];
- this header holds some information about the version, which was used for creating that 7-Zip container data
- _ver_major should contain the major release of LZ5
- _ver_minor should contain the major release of LZ5
- _level should contain the level, the data is packed with
- the other two bytes should be set to zero currently and are reserved for future use
Algorithm author: Przemyslaw Skibinski
- Homepage: https://github.com/inikep/lz5
- Source: https://github.com/inikep/lz5
Codec plugin author: Tino Reichardt
- Homepage: https://mcmilk.de/projects/7-Zip-zstd/
- Source: https://github.com/mcmilk/7-Zip-zstd
Modes:
- threading is supported through skippable frame id 0x184D2A50U
- all levels of v1.5 are supported, which means: 1..15
- the codec is used as archiv handler also, see Lz5Handler.cpp
- this handler is does not use any additional headers, it supports the plain lz5 v1.5 format
- future formats of this algorithm will not follow
- one ID should be okay for this codec
Versions: The 7-Zip codec will be frozen to v1.5 of this codec.
End of document Tino Reichardt, 2017-05-19