OpenEXR
| Filename extension | .exr |
|---|---|
| Developed by | Industrial Light and Magic |
| Initial release | 1999 |
| Latest release |
2.2.0
(10 August 2014) |
| Type of format | High dynamic range imaging |
| Open format? | Yes, Modified BSD License |
| Website | www |
OpenEXR is a high dynamic range raster file format, released as an open standard along with a set of software tools created by Industrial Light and Magic (ILM), under a free software license similar to the BSD license.
It is notable for supporting multiple channels of potentially different pixel sizes, including 64-, 32- and 16-bit floating point values, as well as various compression techniques which include lossless and lossy compression algorithms. It also has arbitrary channels and encodes multiple points of view such as left- and right-camera images.
A full technical introduction of the format is available on the OpenEXR.org website.
OpenEXR, or EXR for short, is a deep raster format developed by ILM and broadly used in the computer-graphics industry, both visual effects and animation.
OpenEXR's multi-resolution and arbitrary channel format makes it appealing for compositing, as it alleviates several painful elements of the process. Since it can store arbitrary channels—specular, diffuse, alpha, RGB, normals, and various other types—in one file, it takes away the need to store this information in separate files. The multi-channel concept also reduces the necessity to "bake" in the aforementioned data to the final image. If a compositer is not happy with the current level of specularity, he or she can adjust that specific channel.
OpenEXR's API makes tools development a relative ease for developers. Since there are almost never two identical production pipelines, custom tools always need to be developed to address problems, e. g. image manipulation issue. OpenEXR's library allows quick and easy access to the image's attributes such as tiles and channels.
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