Choosing EXR compression for VFX pipelines

Hi guys! For production houses getting into an EXR workflow for VFX, the choices for compression can be confusing. Here’s a quick guide.

ZIP - This is your ideal choice as long as you can swing the disk space for storage & transfer. It’s completely lossless, and while all forms of EXR are heavy to read/playback, this is the most forgiving.

PIZ - This is the other primary lossless compression. You can get roughly half of the file sizes of ZIP compression, in exchange for more challenging read/playback. Go for this if you just can’t swing the ZIP file sizes for a particular shot or sequence but are still adamant at keeping it lossless.

DWAA - This is a lossy compression method when even PIZ is too much and you really need to conserve file size. It works on a quality slider, similar to how you control compression of JPEG images. You could compare this to ProRes, but with more manual control. Before you let “lossy compression” scare you away from critical work, a big distinction from something like ProRes is that you are only compressing blocks of color, but you are always keeping 32-bit depth in EXR - while greater compression in ProRes also drops bit depth down to 12 & 8-bit, compounding the quality loss. Don’t be afraid to play with this and find a sweet spot. A lot of people report “negligible” quality loss while massively reducing file sizes.

Hope this helps. Enjoy!