Understanding openEXR image compression methods

This document is now available as handy book on books.rxlab.guide!

The OpenEXR format may seem a bit complicated at first, and a lot of people still claim that “Quicktime Animation has better compression or performance“, that “nothing equals ProRes“, or that “PNG is easier to use“, for example. This is all wrong. Let’s explain!

When using the OpenEXR format, it may be hard to determine what is the best data compression to use, and the question is raised very often. This document is an attempt to answer it, depending on what is your need with the file and what type of image you’re storing.

A compression is said to be the best for a specific need when its read or write speeds better fit the application, and the file size is the smallest available.

Many thanks to Dino Muhić for his expertise about DWA

Types of images

In this document, we’re distinguishing between the following different types of images: