slow exr read

[frodopytlicek]

Hi I encounterer strange behaviour when rendering to raw image with disabled memory frame buffer the resulting exrs are much slower to read. The slowdown is so big we were not able to cache anything in reasonable time. Its big issue for us can someone confirm its a bug?

For viewing sequences we are using Chaos Player 2.10.02
V-Ray version is 6.2.07
3ds Max 2024.2

Thanks

[vladimir_krastev]

Hi, thanks for the thread.

Hi I encountered strange behaviour when rendering to raw image with disabled memory frame buffer the resulting exrs are much slower to read.

I am not reproducing this with a simple scene. Could you compare the results with enabled and disabled frame buffer in a new simple scene? Have you checked if the sizes of the files are the same in both cases? Mine are. Please send us the exr or the sequence that you have trouble with.

[frodopytlicek]

Yes I tried it. With turned off vfb is even smaller which is weird it should be one to one right?
Here are the files. https://mab.to/t/iWpovphmR5U/eu1

[frodopytlicek]

I did another test and even without any render element its slower.

[Joelaff]

Could just be that it is a tiled exr? (I think)

[frodopytlicek]

We use scanlines but it make sense that raw output overrides it.

[Philip Shounev]

Hello frodopytlicek ,

EXRs with disabled memory frame buffer are saved as tiled EXRs which are expected to be slower to read when compared to Scanline EXRs. However, there are couple of options available:

1. Convert the tiled EXR to Scanline EXR using OIIO tool, f.e.
2. Instead of saving an EXR, the output file can be set to .vrimg format which can be converted to EXR using the vrimg2exr tool located in here: C:\ProgramData\Autodesk\ApplicationPlugins\VRay3ds Max2024\bin

[frodopytlicek]

Yes yes this completely makes sense. I just did not realize this. Thank you.