Cryptomatte pass for animation

[LeSill]

Hi guys,

Is it feasible to save the Cryptomatte Pass for animation? It is stated that you must save it from VFB as CXR and alter the extension to EXR. Well, it works for stills, but what about animation? I tried saving a few frames as EXR, but it did not work.
Any suggestions?

Thank you

[bnji]

Hello there,

Could you please elaborate a little bit more about what you're trying to achieve?
Feel free to include as many screenshots as needed to illustrate the issue better.
Looking forward to hearing from you soon.

[LeSill]

Hi,

I've recently discovered that it is also possible to save image sequences/animation in CXR format. I assumed that was a format available just in VFB. I tried saving CRYPTOMATTE using ordinary EXR format, but it didn't work. Now I've checked whether DaVinici Resolve can open CXR format for Cryptomatte masking, and to my surprise, it can. Unfortunately, Photoshop does not support CXR format.

Kind regards

[TomG]

Photoshop does support CXR - you rename it to EXR :) CXR is just EXR file format with extra metadata, that Photoshop will ignore on loading. A batch rename tool can be used if you have several CXRs you want to turn into EXRs. As a note, don't forget Photoshop needs EXR-IO to load EXRs properly (and you will need to chose options for EXR-IO to load cryptomatte data).

The saving an image sequence to CXR and not just saving from the VFB was added in Corona 12 Update 1, https://www.chaos.com/blog/corona-12-update-1, "Added option to save CXR file directly in Save tab in render settings. This should work in batch rendering or when rendering takes."

[TomG]

PS -

for using cryptomatte in PS.

[LeSill]

Thank you for the reply. I have seen that video before, but it is only about the static image saved from VFB.

I first tried saving CXR for passes. It did not save any files, and I received a notice stating that it can only store single images, not animations. Passes cannot be saved as CXR for animation. I could save the REGULAR IMAGE in CXR format for animation. The issue is that it is saved as 32bit, and I am unsure of the color space. As a result, the colors of the beauty pass are unusable in DaVinci Resolve, and repairing them is difficult with unpredictable results. Second, I can't import a CXR file sequence into DaVinci Resolve timeline. I was able to open CXR in the Fusion tab.

The only way to fix this is to save the REGULAR IMAGE as a CXR sequence for the CRYPTOMATTE pass and save the passes as PNG. Passes are saved with linear gama, which can be easily converted to gama 2.2 in DaVinci. Thus, the VirtualBeauty pass can be used as the REGULAR IMAGE.
The problem with storing a standard image as CXR is that it stores all of the passes Corona has to provide. So there are a lot of passes I don't need, and the file is large.

It would be ideal to save the regular image as PNG and the passes as CXR.

[bnji]

Hi there,
Thank you for bringing this to our attention.
This was already reported to the dev team for further investigation.
Thanks again.

For the Corona team:
(Report ID=CC4D-979)
(Report ID=CC4D-970)