Crypto AOV forces 32-bit full precision output, blurred cryptomatte

[vincenzoACPST]

Hi there,

It's been a while since Arnold changed his behavior.

Simple scene, CPU render, crypto enabled, Windows 11:

Until version 5.4.5 you can render 16-bit half-precision exr when crypto_* AOV is enabled, lower filesize, no problem.
Since version 5.4.6 driver is forced to render at 32-bit full precision when crypto_* is enabled, big filesize and a strange blurred crypto_* AOV output.

Tried version 5.5.1, same problem, and this is the message inside Maya:

// Warning: WARNING | Cryptomatte 'crypto_object' cannot be set for driver 'defaultArnoldDriver/driver_exr.RGBA' which is using half precision. Switching to full precision

Is this the "new" behavior since 5.4.6, when "Optimized Cryptomatte and GPU support" enhancement was introduced?
I think the blurry crypto AOV is a bug.

Half-precision exr rendered correct if crypto_* AOV is disabled.

Does anyone have this behavior?

To sum up:

Differences:

 

 

[Stephen.Blair]

Hi

They both look blurry to me.

Even with the old cryptomatte, the cryptomatte AOVs are all float.
Only the deprecated, unused preview AOV was left half.

Here's the oiiotool -v --info channel list for a render with Arnold 7.3.4 (MtoA 5.4.4)

The channels with 00, 01, and 02 are where the cryptomatte data lives.

channel list: 
    
R (half), G (half), B (half), A (half), 
crypto_asset.R (half), crypto_asset.G (half), crypto_asset.B (half)
crypto_asset00.R (float), crypto_asset00.G (float), crypto_asset00.B (float), crypto_asset00.A (float)
crypto_asset01.R (float), crypto_asset01.G (float), crypto_asset01.B (float), crypto_asset01.A (float)
crypto_asset02.R (float), crypto_asset02.G (float), crypto_asset02.B (float), crypto_asset02.A (float)
crypto_material.R (half), crypto_material.G (half), crypto_material.B (half)
crypto_material00.R (float), crypto_material00.G (float), crypto_material00.B (float), crypto_material00.A (float)
crypto_material01.R (float), crypto_material01.G (float), crypto_material01.B (float), crypto_material01.A (float)
crypto_material02.R (float), crypto_material02.G (float), crypto_material02.B (float), crypto_material02.A (float)
crypto_object.R (half), crypto_object.G (half), crypto_object.B (half)
crypto_object00.R (float), crypto_object00.G (float), crypto_object00.B (float), crypto_object00.A (float)
crypto_object01.R (float), crypto_object01.G (float), crypto_object01.B (float), crypto_object01.A (float)
crypto_object02.R (float), crypto_object02.G (float), crypto_object02.B (float), crypto_object02.A (float)

Just for my own future reference, here's where the old cryptomatte code did the check for half precision:
https://github.com/Psyop/CryptomatteArnold/blob/master/cryptomatte/cryptomatte.h#L1079

[vincenzoACPST]

Thanks for your reply.

The problem is in non-cryptomatte outputs, they are all rendered in full float, resulting in size gain, even if in Maya half-precision is checked.
I've added some other AOV. Here's the oiiotool -v --info channel list for both images:

Mtoa 5.4.5. Mixed precision, only crypto are full.

600 x 600, 58 channel, half/half/half/half/half/half/half/half/half/half/float/float/float/float/float/float/float/float/float/float/float/float/half/half/half/float/float/float/float/float/float/float/float/float/float/float/float/half/half/half/float/float/float/float/float/float/float/float/float/float/float/float/half/half/half/half/half/half openexr

channel list:

R (half), G (half), B (half), A (half),
coat.R (half), coat.G (half), coat.B (half),
crypto_asset.R (half), crypto_asset.G (half), crypto_asset.B (half),
crypto_asset00.R (float), crypto_asset00.G (float), crypto_asset00.B (float), crypto_asset00.A (float),
crypto_asset01.R (float), crypto_asset01.G (float), crypto_asset01.B (float), crypto_asset01.A (float),
crypto_asset02.R (float), crypto_asset02.G (float), crypto_asset02.B (float), crypto_asset02.A (float),
crypto_material.R (half), crypto_material.G (half), crypto_material.B (half),
crypto_material00.R (float),crypto_material00.G (float), crypto_material00.B (float), crypto_material00.A (float),
crypto_material01.R (float), crypto_material01.G (float), crypto_material01.B (float), crypto_material01.A (float),
crypto_material02.R (float), crypto_material02.G (float), crypto_material02.B (float), crypto_material02.A (float),
crypto_object.R (half), crypto_object.G (half), crypto_object.B (half),
crypto_object00.R (float), crypto_object00.G (float), crypto_object00.B (float), crypto_object00.A (float),
crypto_object01.R (float), crypto_object01.G (float), crypto_object01.B (float), crypto_object01.A (float),
crypto_object02.R (float), crypto_object02.G (float), crypto_object02.B (float), crypto_object02.A (float),
diffuse.R (half), diffuse.G (half), diffuse.B (half),
specular.R (half), specular.G (half), specular.B (half)

Mtoa 5.5.1. All channels forced in full precision.

600 x 600, 58 channel, float openexr

channel list:

R, G, B, A,
coat.R, coat.G, coat.B,
crypto_asset.R, crypto_asset.G, crypto_asset.B,
crypto_asset00.R, crypto_asset00.G, crypto_asset00.B, crypto_asset00.A,
crypto_asset01.R, crypto_asset01.G, crypto_asset01.B, crypto_asset01.A,
crypto_asset02.R, crypto_asset02.G, crypto_asset02.B, crypto_asset02.A,
crypto_material.R, crypto_material.G, crypto_material.B,
crypto_material00.R, crypto_material00.G, crypto_material00.B, crypto_material00.A,
crypto_material01.R, crypto_material01.G, crypto_material01.B, crypto_material01.A,
crypto_material02.R, crypto_material02.G, crypto_material02.B, crypto_material02.A,
crypto_object.R, crypto_object.G, crypto_object.B,
crypto_object00.R, crypto_object00.G, crypto_object00.B, crypto_object00.A,
crypto_object01.R, crypto_object01.G, crypto_object01.B, crypto_object01.A,
crypto_object02.R, crypto_object02.G, crypto_object02.B, crypto_object02.A,
diffuse.R, diffuse.G, diffuse.B,
specular.R, specular.G, specular.B

Please, take a closer look at the image I sent, it's a screenshot from Nuke and the 2 images are zoomed in, but the second seams the first with a blur size of 2.
Anyway I have uploaded both images and scene. Look at the different size 10.073 Kb vs 2.378 Kb and check the cryptomatte output.

Thanks.

[Stephen.Blair · Accepted solution]

Ok, I logged a ticket for "Cryptomatte changes all AOVs to float" issue

[vincenzoACPST]

Great, thank you so much!