pybcj
bcj filter library
Decision gist · record as of 2026-08-14
Yes, if you need BCJ filtering for executable compression. The package is actively maintained, has no runtime dependencies, supports current Python versions, and offers prebuilt wheels for most platforms. The LGPL-2.1-or-later license requires review if you plan to distribute proprietary software. The medium install friction is typical for compiled extensions and should not be a barrier on standard platforms.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- On MSYS2/Mingw64, set environment variable SETUPTOOLS_USE_DISTUTILS=stdlib before installation.
- Requires Python 3.10 or later.
- Medium install friction due to compiled C extensions; prebuilt wheels available for Python 3.10–3.14 on macOS, Linux (including musl), and Windows across multiple architectures.
License · maintenance · safety
LGPL-2.1-or-later (copyleft) — Licensed under LGPL-2.1-or-later (copyleft). Derivative works and distributions must comply with copyleft obligations; proprietary or closed-source projects should review compatibility before use.
last release 2026-07-16 (29 days) · last repo commit 2026-07-16 · 4 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 9,283,758 downloads/mo, #1,550 on PyPI
Alternatives
Verify before relying
pip install pybcj
import pybcj
# pybcj provides BCJ filter functions for use with compression libraries- Specific API surface and available filter functions for each supported architecture (x86, x86_64, Arm, Arm64, ArmThumb, Sparc, PPC, IA64)
- Whether pybcj is intended as a standalone tool or primarily as a dependency for other compression libraries
- Performance characteristics and typical compression gains when used with LZMA
What it is and what it does
pybcj is a Python binding to a C implementation of the BCJ (Branch-Call-Jump) filter, a preprocessing technique used in data compression to improve compression ratios for executable binaries. The filter works by replacing relative branch addresses with absolute ones, allowing downstream LZMA compressors to identify and deduplicate targets more effectively. The underlying C code is derived from p7zip, the portable 7-zip implementation, and supports multiple processor architectures including Intel/AMD x86/x86_64, Arm/Arm64, ArmThumb, Sparc, PPC, and IA64.
The package is built as a compiled extension with prebuilt wheels for modern Python versions (3.10–3.14) across major platforms. It has no runtime dependencies and is classified as Beta in development status, though the PyPI classifier indicates Production/Stable. It is actively maintained, with the latest release 29 days old and the repository not archived.
Use it for
- Preprocessing executable binaries before LZMA compression to achieve higher compression ratios, similar to 7-zip's default behavior
- Building compression utilities or libraries that need BCJ filtering for multiple CPU architectures
- Integrating BCJ preprocessing into data archival or backup tools that target executable files
- Cross-platform binary optimization where compression size matters (embedded systems, distribution packages)
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you need BCJ filtering for executable compression.
The package is actively maintained, has no runtime dependencies, supports current Python versions, and offers prebuilt wheels for most platforms. The LGPL-2.1-or-later license requires review if you plan to distribute proprietary software. The medium install friction is typical for compiled extensions and should not be a barrier on standard platforms.
Install
pybcj on PyPI
Before you install
Medium install friction due to compiled C extensions; prebuilt wheels available for Python 3.10–3.14 on macOS, Linux (including musl), and Windows across multiple architectures. Last release 29 days ago; repository is active and not archived.
On MSYS2/Mingw64, set environment variable SETUPTOOLS_USE_DISTUTILS=stdlib before installation. Requires Python 3.10 or later.
License in practice
Licensed under LGPL-2.1-or-later (copyleft). Derivative works and distributions must comply with copyleft obligations; proprietary or closed-source projects should review compatibility before use.
Quickstart
pip install pybcj
import pybcj
# pybcj provides BCJ filter functions for use with compression librariesVerify before relying
- Specific API surface and available filter functions for each supported architecture (x86, x86_64, Arm, Arm64, ArmThumb, Sparc, PPC, IA64)
- Whether pybcj is intended as a standalone tool or primarily as a dependency for other compression libraries
- Performance characteristics and typical compression gains when used with LZMA
Package facts
| License | LGPL-2.1-or-later copyleft |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Medium. Platform-specific wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 29 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 9,283,758 / month, #1,550 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 5 - Production/StableOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIXOperating System :: POSIX :: LinuxProgramming Language :: PythonProgramming Language :: Python :: 3Programming Language :: Python :: 3 :: OnlyProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPyTopic :: Software Development :: Libraries :: Python Modules |
Evidence: pybcj-1.0.8-cp310-cp310-macosx_10_9_universal2.whl; pybcj-1.0.8-cp310-cp310-macosx_10_9_x86_64.whl; pybcj-1.0.8-cp310-cp310-macosx_11_0_arm64.whl; pybcj-1.0.8-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; pybcj-1.0.8-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; pybcj-1.0.8-cp310-cp310-musllinux_1_2_aarch64.whl; pybcj-1.0.8-cp310-cp310-musllinux_1_2_x86_64.whl; pybcj-1.0.8-cp310-cp310-win_amd64.whl; pybcj-1.0.8-cp310-cp310-win_arm64.whl; pybcj-1.0.8-cp311-cp311-macosx_10_9_universal2.whl; pybcj-1.0.8-cp311-cp311-macosx_10_9_x86_64.whl; pybcj-1.0.8-cp311-cp311-macosx_11_0_arm64.whl; pybcj-1.0.8-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; pybcj-1.0.8-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; pybcj-1.0.8-cp311-cp311-musllinux_1_2_aarch64.whl; pybcj-1.0.8-cp311-cp311-musllinux_1_2_x86_64.whl; pybcj-1.0.8-cp311-cp311-win_amd64.whl; pybcj-1.0.8-cp311-cp311-win_arm64.whl; pybcj-1.0.8-cp312-cp312-macosx_10_13_universal2.whl; pybcj-1.0.8-cp312-cp312-macosx_10_13_x86_64.whl
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