Open color luts for mplay

[Korhon]

Hi! I already postet this at the sidefx/forum, but no response so posting it here also

Was wondering if anyone had any luck creating opencolors sonyanimation lut and sonyvfx lut for mplay? When I create a lut from nuke 7 in lut or blut format the result doesnt match what the sony luts are doing in nuke. In mplay or renderview the bright values doesnt get cliped the right way. Looks kinda clamped.

So is there anyone here that had any luck creating luts for mplay that clips bright values correct? What is the workflow? Or is this a limitation of luts or mplay?

Thanks!

[Hans Joergen]

Hei hei!

We're currently working on this now and we've had some good results using ociobakelut to bake out the spi-vfx/srgb8 ( "kodak film look" ) profile.

The command I use is:

ociobakelut --format houdini --inputspace lnf --shaperspace lg10 --outputspace srgb8 OCIO-houdini_spi-vfx_lnf_to_srgb8.lut

I did a comparison of the same lut applied in nuke and mplay and I notice only small differences in the darker regions, i.e. the mplay lut is desaturated in the darker regions. No idea why.

As for the clipping problems you're describing I'm not quite sure what you mean, but we see what's expected; In our mplay the "overly" bright regions get the S-curve shape that "compresses" the highlights into the ~0-1.x range. Sometimes ( seemingly a bug ) it seems mplay clips all values above 1.0 the image in the framebuffer making it impossible to adjust exposure to get the correct results. We fix this by using the Swedish button

If you're on windows and unable to get a hold of opencolorio, I've heard that you can use the AfterFX OCIO plugin to generate luts, or you could install ubuntu on a virtual machine and use the command above using ociobakelut.

I've attached the lut we use, so you can check.

As for the Sony animation view lut, It does clip everything quite heavily.

Edit: I may not have phrased myself correcly here, so rather, the Sony animation view lut seems more like a heavy s-curve that doesn't allow values above 1, it seems.

Hans Joergen Kjaernet / Storm Studios

sony_lut_lnf_to_srgb.tar.gz

Edited April 18, 2013 by Hans Joergen

[sam.h]

Thanks for the file