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 the EXR format is to accurately and efficiently represent high-dynamic-range scene-linear image data. This is a significant difference from most image formats, which store images that are ready for display. Software may need to process OpenEXR images differently from other image 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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April 29, 2026 - OpenEXR 3.4.11 Released

Patch release that addresses the following security vulnerabilities:

Shift exponent overflow in readVariableLengthInteger() (ImfIDManifest.cpp) * CVE-2026-42216 Out-of-bounds read in IDManifest::init() during prefix expansion * CVE-2026-41142 Integer overflow in ImageChannel::resize leads to heap OOB write via OpenEXRUtil public API

Heap-buffer-overflow in DwaCompressor_uncompress * OSS-fuzz 505062709 Null-dereference READ in Imf_3_3::prefixFromLayerName

Build fixes:

  • Fix Windows ARM64EC build issues and correct SIMD ARM NEON path for ARM64/EC

Also, some minor documentation updates:

  • GitHub Security Advisories are the preferred way of reporting vulnerabilities, not email.

  • Some clarification around handling of UFT-8 of file paths

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

You can install OpenEXR using package managers or build the library yourself from the source on github following the compile instructions

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

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