OpenEXR

OpenEXR provides the specification and reference implementation of the EXR file format, the professional-grade image storage format of the motion picture industry.

The purpose of EXR format is to accurately and efficiently represent high-dynamic-range scene-linear image data. This is a significant difference to most image formats, which store images that are ready for display. Software that handles OpenEXR images may need to process them differently to images in other formats such as JPEG (see Scene-Linear Image Representation for more details). OpenEXR files have strong support for multi-part, multi-channel use cases, and extensive representation of associated metadata.

OpenEXR is widely used in host application software where accuracy is critical, such as photorealistic rendering, texture access, image compositing, deep compositing, and DI.

OpenEXR is a project of the Academy Software Foundation.

Latest News

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March 23, 2025 - OpenEXR 3.3.3 Released

Patch release with miscellaneous bug/build/documentation fixes:

  • 🐛 Fix a bug involving deep tiled images

  • 🐛 Adjust the clamping on the dwa compression (Issue 1982)

  • 🐛 Address issues with small exr files and header parse (Issue 1984)

  • 🐛 Fix crash if user does not provide memory when filling deep framebuffer

  • 🐛 Fix bad pointer SSE math causing out-of-bounds access

  • 🐛 Fix potential buffer overwrite with zip data

  • 🐛 Fix usage of utf-8 filenames for windows

  • 🐛 Fix regression in reading EXR images on 32bit Windows involving atomic_compare_exchange_strong

  • 🐛 Add checks to avoid using optimizations when inappropriate (Issue 1949)

  • 🐛 Convert dwa encoder to use algorithm quantize (Issue 1915)

  • 🐛 Fix incorrect v3 array size validation

  • 🚀 Add minor huf encode / decode performance optimizations

  • 🛠 Add numpy dependency to python wrapper (Issue 1919)

  • 🛠 Remove duplicate cmake dependency from skbuild plugin (Issue 1958)

  • 🛠 Don’t set the library postfix in the cmake cache (Issue 1981)

This version also introduces a new tool, exrmetrics, a utility to help analyize file i/o times and compression ratios. See exrmetrics for details.

This version also officially installs the exrcheck utility, formerly built for internal use but not installed.

This version also publishes the python bindings for arm64 on Ubuntu and macOS.

Imath

The OpenEXR project includes Imath, a basic, light-weight, and efficient C++ representation of 2D and 3D vectors and matrices and other simple but useful mathematical objects, functions, and data types common in computer graphics applications, including the half 16-bit floating-point type.

Imath also includes optional python bindings for all types and functions, including optimized implementations of vector and matrix arrays.

Quick Start

For a simple program that uses the C++ API to read and write a .exr file, see the Hello, World examples.

Community

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