bzip2 vs Zstandard

bzip2 is a free data compressor for creating and reading compressed files. It provides command-line tools and supports BZ2 (.bz2), BZ (.bz), TBZ2 (.tbz2), and TBZ (.tbz) formats. The maker says its compression typically comes within 10% to 15% of the best available PPM-family techniques, while running around twice as fast for compression and six times faster for decompression. Its limited media-error recovery may allow undamaged portions of a damaged file to be decompressed. The separate libbzip2 library lets programs read and write .bz2 files or compress data in memory. Command-line flags resemble GNU Gzip's, and the distribution should compile without modification on Unix and Win32 systems. bzip2 dates to 1996 and is open source under a BSD-style license. The official site lists version 1.0.8 as stable and offers source code, not executables. Building has a good chance of success with an ANSI C compiler and at least 8 megabytes of spare memory; the source tarball includes documentation in several formats.

Zstandard is a lossless compression algorithm for real-time workloads, with controls that let users shift compression speed and ratio in small increments. Its reference implementation includes a C library and a command-line utility that creates and decodes .zst, .gz, .xz, and .lz4 files. The format is stable and documented in RFC 8878; the implementation is available under BSD or GPLv2. For small, related samples, training can produce a data-specific dictionary to improve compression. The same dictionary must be present for both compression and decompression, and the samples need to be correlated; there is no universal dictionary. The project documents builds with Make, CMake, Meson, Visual Studio, Buck, and Bazel, plus installation using vcpkg and Conan. Community bindings and ports are listed for languages including Python, Rust, Java, C#, JavaScript, Go, PHP, and Swift. Zstandard is free, with a free plan, and supports Linux, Windows, and macOS.