Standalone denoiser - error reading EXR

[akos_kiss]

Hi!
I'm getting the following error message if i want to use the standalone denoiser for vray. 3.7. with an OpenEXR multilayer sequence with PXR24 compression. I'm also having the same issue with the DWAA and DWAB compression types.

error: [DenoiserApp::readMultiChannel] Error reading raw image file name
[ExrFile::ParseFile] OpenEXR error: Error reading pixel data from image file
No frame buffer specified as pixel data destination.


I've also tired the new vray 5 denoiser but as it turns out there was some kind of change in the renderpass names from v3.7 to v5
I have the denoiser channel enabled.

Anyone else expreiencing this?

[aleksandar.kasabov]

Hello @akos_kiss,

I apologize for the delayed reply.

Could you please share a test .exr image where the issue is reproducible? Does this happen with any file or a particular one only? Also, does it happen with PXR24, DWAA, and DWAB compression methods only or it also happens with other methods?

[akos_kiss]

Hi @aleksandar.kasabov
Sorry it took a bit of time to get back to this issue. Sadly i get the same issue with the other compressions as well.
And a side note for that matter, i tried using the save vfb images for exr-s but i couldn't choose the compression and multilayered options. Am is missing something? I couldn't find more info in the documentation.

The error i get:

Reading file "D:\007_Render\001_PreRender\dragon_0_30_VRAY_ ZIP_ 1_0000.exr"
error: [DenoiserApp::readMultiChannel] Error reading raw image file name "D:\007_Render\001_PreRender\dragon_0_30_VRAY_ ZIP_ 1_0000.exr" : [ExrFile::ParseFile] OpenEXR error: Error reading pixel data from image file "D:\007_Render\001_PreRender\dragon_0_30_VRAY_ ZIP_ 1_0000.exr". No frame buffer specified as pixel data destination.

I uploaded the .exr sequence and the c4d file to this link:

LINK

Thanks!

[aleksandar.kasabov]

Hello akos_kiss,

Upon checking your scene it seems like the issue is caused by the "Z-Depth" render element. Removing it seems to be fixing the issue. Alternatively, you can save the images as .vrimg, then use the "vrimg2exr" tool, located in the same folder as the vdenoise tool. You can then choose the compression type and use the exr (or vrimg) with the standalone denoiser. I hope this is of help.

[ezleszeken]

Hello @aleksandar.kasabov

I have a few questions regarding this method. I tried .exr sequence without the z-depth but this is a bit of an inconvenience as i would like to use the z-depth pass. I was trying to save the animations as a .vrimg sequence but i couldn't make the vray output system work.
First of all it didn't save it as a vrimg but as exr. and when i tried to save it as exr it waved it as a multipart exr (every pass a separate exr) instead of a multilayered one.

Can someone please explain how can i make it work? I couldn't get access to the old vrayforc4d forum where I remember maybe @RwVision or @sirio76 posted a longer thread about animations and the denoiser? Could you guy please help me a bit with this?

Using this in Vray 5 is pretty straight forward and it works fine, but we have a few projects in 3.7 where we would need a solution like this. The other this is that i would like to use cryptomatte passes for mattes as it offers a bit easier setup. As i understand the cryptomatte pass is only supported when the 32-bit .exr (I assume this works with vrimg also?) is saved from the VFB because of the metadata and manifest needed for it to work.

• The first thing i did is to enable Show VFB window when rendering an animation
• I added the cryptomatte RE and Denoiser RE (set the Mode to "Only generate render elements" - because i like to use the standalone denosier, set the Type to "Denoiser render elements separately" )
• In the render settings on the translator tab I ticked the Save VFB images, set the VFB file location and name, and the format to Vrimg or Exr. At this point i thought that on the Render Elements tab i can set up the exr compression for the translator settings. So i set the compression to PXR24 (as it is really efficient) and pressed Render.
• To my surprise the rendering strated but i couldn't get it to save as ONE .exr or ONE .vrimg file all the passes where saved out separately for some reason.

I'm really confused what the V-ray Bridge/ Render elements tab does.
I don't understand how can i save out one exr (with my selected compression) or one vrimg with all the passes.

[sirio76]

I’m not sure you are able to save multilayer .exr but you can do like this to get all the elements:
-in the translator tab save in .vrimg format (seems to remember that you need to add manually the file extension)
-this will save the image including all the render elements
-then you can open the file using the plugin ProEXR (free for PS and other application)
-in alternative you can use the vrimg2exr tool to convert the .vrimg in multilayer .exr file

[aleksandar.kasabov]

Hello,

As sirio76 mentioned above you will need to add your desired rendered elements in the V-Ray Multipass Manager, then in the Translator tab of the V-Ray render settings enable "Save VFB images", set the format to VrImg, and set the path for the file. You will need to add the file extension manually in the path. Please check this screenshot. Once you render the image, the saved output will include all your render elements.

[ezleszeken]

@aleksandar.kasabov & @sirio76 Thank you for the help! Yeah sadly it looks like can't save multilayered exr-s (or multipart as it is in the RE tab). I wanted to skip the vrimg to exr to denioser to exr 3 step process because of the immense amount of redundant data generated this way. Oh well is what it is. Thanks again for the help! I will check if the vrimg works well with the z-depth pass and denoiser combination.