I know that cxr exports the metadata in the cryptomatte mask, but the file is 5 times larger in megabytes, but it does not save the tonemapp from the frame buffer. Would it be possible to export in exr format but with the same compression as is done in vray?
This sounds like two requests - one, which is something planned, is to have tone mapped Beauty in the CXR. However, the second is something relating to compression (btw compression is definitely already applied in the CXR). I am not sure if the first request resolves your issue for using cryptomatte in Nuke (I mean, it does, but is there the extra part to your request, which is a question about compression - not necessary for using compositing in Nuke, but maybe something you are asking about anyway?). Thanks!