What's your favorite flavor of EXR compression?

Looking for that balance of speed vs file size.

  • Scanline
  • Multi_Scanline
  • RLE
  • PXR24
  • PIZ
  • DWAB
  • DWAA
  • B44A
  • B44
  • Uncompressed

0 voters

And to even open this up further, it would be nice to have a single place where all this information lives. So let’s collect everything we know about EXR compression in this thread.

So if you know what compression nuke likes, etc., please share that here.

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PIZ is lossless and usually the best option for images captured with a camera (as opposed to CGI).

PIZ has a better compression ratio than ZIP, so files will be smaller but are more computationally expensive to play back. Conversely, ZIPs take longer to write but are faster to read.

Wikipedia provides a nice summary:

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Thanks!

Nuke likes zips the most - note there is a difference between zip and zips(1scanline), the name gives it away and nuke can then read like only half the scanlines at a time speedings things up.

Oh and btw ZIP compression is not your grandmas ZIP file compression , they have similarities but its not the same.

All losless conpressions will give you the same result the difference is in the encoding and decoding speed, you are very much trading storage bandwith for cpu cycles , its hust lioe choosing the different compression allgorithms in 7zip or keka or whatever, they wont change the file at all.

(another example of losless compression is FLAC)

Other thing to keep an eye out of is how the exr deals wirh multilayers, you can interleave the layers in different ways with “multipart” exrs beign what you want as those csn read a single channel from a exr those saving tons of bandwith.

Another thing is: dont put log or gamma encoded data into exrs, this comes down to that it saves data in floating point and not integer so 16bit float is definetely not the same as 16bit integer! 16bit float woth log data is bascially like 10bit DPX in terms of precision.

Why nobody has implemented things like compressed DPX is beyond me. (dpx-C exists)

compression; if you are not way too rich you use dwaa or dwab which is losssy compressed! … its like prores vs dpx while giving you all the nice exr festures like float data and multichannels and all the metadata in the world, dont be scared of dwaa, its great, you can vary the conpression yourself, 150 is like jpeg size in 16bit float!!

Last thing is that 32bit matters for 3D AOVs, like depth passes and UV(ST) maps. you can run into weird issues when you do 32->16 bit conversions with this data as rounding occurs.

Update actual last thing is; anyone that is requesting uncompressed EXR needs to rethink life. (Out of spite you shall compress them using 7zip before sending… or you should in genrall do that with uncompressed media but thats another story for another time)

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