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  1. 8bd7418 DO NOT MERGE by Xin Li · 6 days ago master
  2. 419ef7d Snap for 4386413 from db96f7cadd60d24ad028d50d82d7fd9ef1aa12ac to pi-release by android-build-team Robot · 1 year, 2 months ago p-preview-1 pie-arc pie-cts-release pie-gsi pie-platform-release pie-r2-release pie-r2-s1-release pie-r2-s2-release pie-release pie-release-2 pie-s2-release pie-vts-release android-9.0.0_r1 android-9.0.0_r10 android-9.0.0_r17 android-9.0.0_r18 android-9.0.0_r2 android-9.0.0_r3 android-9.0.0_r5 android-9.0.0_r6 android-9.0.0_r7 android-9.0.0_r8 android-9.0.0_r9 android-cts-9.0_r1 android-cts-9.0_r2 android-cts-9.0_r3 android-cts-9.0_r4 android-cts-9.0_r5 android-p-preview-1 android-p-preview-4 android-p-preview-5 android-vts-9.0_r4 android-vts-9.0_r5
  3. db96f7c Use -Werror in external/lz4 am: 059522dc16 am: 2332741e72 am: 149bd34633 by Chih-Hung Hsieh · 1 year, 2 months ago master-cuttlefish-testing-release pie-dev pie-dr1-dev pie-dr1-release pie-qpr1-release pie-qpr1-s1-release pie-qpr1-s2-release pie-qpr1-s3-release android-9.0.0_r11 android-9.0.0_r12 android-9.0.0_r16 android-9.0.0_r19 android-9.0.0_r20 android-9.0.0_r21 android-9.0.0_r22 android-p-preview-2 android-p-preview-3 android-wear-9.0.0_r1 android-wear-9.0.0_r2 android-wear-9.0.0_r3
  4. aef7cb1 Use -Werror in external/lz4 am: 059522dc16 am: 2332741e72 am: 149bd34633 by Chih-Hung Hsieh · 1 year, 2 months ago android-wear-p-preview-2
  5. 149bd34 Use -Werror in external/lz4 am: 059522dc16 am: 2332741e72 by Chih-Hung Hsieh · 1 year, 2 months ago

LZ4 - Extremely fast compression

LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

Speed can be tuned dynamically, selecting an “acceleration” factor which trades compression ratio for more speed up. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.

LZ4 library is provided as open-source software using BSD 2-Clause license.

masterBuild Status Build status coverity
devBuild Status Build status

Branch Policy:

  • The “master” branch is considered stable, at all times.
  • The “dev” branch is the one where all contributions must be merged before being promoted to master.
    • If you plan to propose a patch, please commit into the “dev” branch, or its own feature branch. Direct commit to “master” are not permitted.


The benchmark uses lzbench, from @inikep compiled with GCC v6.2.0 on Linux 64-bits. The reference system uses a Core i7-3930K CPU @ 4.5GHz. Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.

memcpy1.0007300 MB/s7300 MB/s
LZ4 fast 8 (v1.7.3)1.799911 MB/s3360 MB/s
LZ4 default (v1.7.3)2.101625 MB/s3220 MB/s
LZO 2.092.108620 MB/s845 MB/s
QuickLZ MB/s600 MB/s
Snappy MB/s1550 MB/s
LZF v3.62.073365 MB/s820 MB/s
Zstandard 1.1.1 -12.876330 MB/s930 MB/s
Zstandard 1.1.1 -33.164200 MB/s810 MB/s
zlib deflate 1.2.8 -12.730100 MB/s370 MB/s
LZ4 HC -9 (v1.7.3)2.72034 MB/s3240 MB/s
zlib deflate 1.2.8 -63.09933 MB/s390 MB/s

LZ4 is also compatible and well optimized for x32 mode, for which it provides +10% speed performance.


The raw LZ4 block compression format is detailed within lz4_Block_format.

To compress an arbitrarily long file or data stream, multiple blocks are required. Organizing these blocks and providing a common header format to handle their content is the purpose of the Frame format, defined into lz4_Frame_format. Interoperable versions of LZ4 must respect this frame format.

Other source versions

Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.