Freedom251 › Image Compression Software
Jpegli
by Jpegli
What Jpegli is
Jpegli is a free JPEG encoder and decoder implementation designed as a drop-in replacement for software using the libjpeg62 API and ABI. It supports lossy JPEG compression through an API on Linux, macOS, and Windows. Building the project creates cjpegli and djpegli command-line binaries and a libjpeg.so.62.3.0 shared library. The encoder accepts 16-bit unsigned and 32-bit floating-point input buffers, while the decoder can produce output in those formats. Color conversion, chroma subsampling, and DCT calculations use floating-point precision before quantization. A distance parameter controls encoding quality, and adaptive dead-zone quantization applies different zero-coefficient thresholds in noisy and smooth regions. JPEGs with an XYB ICC profile can use specialized channel tables without conversion to YCbCr. Google says Jpegli compresses high-quality images 35% more than traditional JPEG codecs and remains interoperable with the original JPEG standard and conventional 8-bit format. It uses a BSD 3-Clause license.
Who it suits
Jpegli is intended for developers building or replacing JPEG functionality in software. It suits projects needing API compatibility, command-line tools, or higher-precision image buffers.
What it does well
- Drop-in libjpeg62 API and ABI compatibility
- Supports 16-bit and floating-point buffers
- Builds command-line binaries and shared library
- BSD 3-Clause licensed
- Cross-platform Linux, macOS, and Windows support
What to know first
- Only JPEG format is listed
- Compression mode is lossy
- Windows builds require MSYS2 instructions
- No free trial is listed
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Jpegli | BSD-3-Clause licensed JPEG encoder and decoder library | Free |
As github.com lists them, read 12 Oct 2026. The maker's own page has the final word.
Verdict
Jpegli provides a free, compatible JPEG library with command-line outputs and floating-point processing. Its documented build process and JPEG-only scope matter for integration planning.
Facts from Jpegli's own pages
- Adaptive quantization
- Jpegli uses adaptive dead-zone quantization with higher zero-coefficient thresholds in noisy image regions than in smoother regions. · github.com, 12 Oct 2026
- API access
- Yes · github.com, 24 Sept 2026
- Build outputs
- Building the project produces cjpegli and djpegli binaries and a libjpeg.so.62.3.0 shared library that can replace a system library with the same name. · github.com, 11 Oct 2026
- Build targets
- The build documentation describes cross-compiling for other architectures and mentions additional environment setup for Windows targets. · github.com, 11 Oct 2026
- Command line and library
- Building the project produces cjpegli and djpegli binaries and a libjpeg shared library intended as a drop-in replacement for the system library of the same name. · github.com, 12 Oct 2026
- Compatibility
- Google describes Jpegli as a fully interoperable encoder and decoder that complies with the original JPEG standard and its conventional 8-bit format. · opensource.googleblog.com, 12 Oct 2026
- Compression
- Google says Jpegli can compress high quality images 35% more than traditional JPEG codecs. · opensource.googleblog.com, 12 Oct 2026
- Compression modes
- lossy · github.com, 24 Sept 2026
- Decoder output
- The decoder supports 16-bit unsigned and 32-bit floating-point output buffers. · github.com, 11 Oct 2026
- Decoder outputs
- The decoder supports 16-bit unsigned and 32-bit floating point output buffers. · github.com, 12 Oct 2026
- Encoder input
- The encoder supports 16-bit unsigned and 32-bit floating-point input buffers. · github.com, 11 Oct 2026
- Encoder inputs
- The encoder supports 16-bit unsigned and 32-bit floating point input buffers. · github.com, 12 Oct 2026
- Floating-point processing
- Color-space conversion, chroma subsampling, and DCT use floating-point precision before final quantization. · github.com, 11 Oct 2026
- Founded
- 2024 · github.com, 19 Oct 2026
- Free plan
- Yes · github.com, 24 Sept 2026
- Integration
- The library is designed as a drop-in replacement compatible with the libjpeg62 API and ABI. · github.com, 11 Oct 2026
- Intended users
- The README identifies the Git guide as being for developers and provides build and testing instructions for the project. · github.com, 11 Oct 2026
- License
- The repository lists the BSD-3-Clause license. · github.com, 12 Oct 2026
- macOS build
- The repository includes separate instructions for building on macOS. · github.com, 12 Oct 2026
- Patent grant
- Google grants a perpetual, worldwide, non-exclusive, no-charge, royalty-free patent license for specified claims necessarily infringed by the implementation, subject to stated termination conditions. · github.com, 11 Oct 2026
- Purpose
- Jpegli is an improved JPEG encoder and decoder implementation with API and ABI compatibility with libjpeg62. · github.com, 12 Oct 2026
- Quality control
- Encoding quality can be set with a distance parameter analogous to JPEG XL’s distance parameter. · github.com, 12 Oct 2026
- Support
- The repository asks users to report bugs or other issues by opening a GitHub issue. · github.com, 12 Oct 2026
- Supported formats
- JPEG · github.com, 24 Sept 2026
Where Jpegli stands on Freedom251
- Image Compression Software#40 of 85