Draft exr to mov ERROR - Assertion failed



Draft is returning this error randomly when making a movie from an exr.

When trying to check /tmp/FranticRegressions/Draft/git_draft_DraftAll/FranticImageLibrary/./frantic_image/operators/composite_operators.hpp there is no file or directory.

Our setup:
Draft 1.6.2

Also attaching a sample frame.

pp_050_flare_v1.4578.exr.zip (9.83 MB)


Thank you for your report!

I think that error means that your alpha channel has a “Not a Number” value. Such values come from wonky operations like 0/0. I don’t see any such values in the image that you sent to me, so I think it must be coming from some processing in your script.

In your case, I suspect you don’t actually need the image’s alpha channel. So, as a workaround, I would suggest modifying your script to remove the image’s alpha channel before it reaches the compositing operation. I’d remove it right after loading the EXR file.

Somewhere in your script, you’ll have a line like this to load the EXR image:

img = Draft.Image.ReadFromFile(...)

Right after that, you can run the following commands to remove the alpha channel:

if img.HasChannel('A'): img.RemoveChannel('A')

If you’d like more specific instructions, please send us a copy of your Draft script. You can send us files over this forum, or by using our ticket system.

Please let us know if this works for you!

As for the underlying problem, we could look into it further if you’d like to send us a copy of your Draft script and LUT file (/_config/ocio/alexa_ocioConfig_v3/luts/AlexaV3_K1S1_LogC2Video_Rec709_LL_nuke3d.cube).