Chroma Key using Boris

I feel I must be missing something obvious and fundamental.

I want to do a chroma key using one of the OFX filters. For example Boris Chroma Key.


I have a solid color set up on video track one and a video with a subject shot on a red screen (yeah red) on video track 2. I add an alpha output in the color page and add a node and link the alpha to the output. I add the BCC Chroma Key effect and use the eyedropper to select the color to key out. I can see the matte it has created but it does not chorma key the person on to the colour back ground I have but rather just shows the subect over black. How do I get it to key over my video track 1 (the solid color)?

I'm still scratching my head...

I add BCC Chroma Key and I select use "OFX alpha" and it works, it keys it over the other layer but I use BCC Chroma Key studio it doesn't.

I also seem to have problems getting keying to work in Resolve. I tried BCC Primatte and ran into the same problem you posted with BCC Chroma Studio.

No problems using these in Fusion but somehow the keying workflow in Resolve eludes me.

I just tried BCC Primatte Studio in Fusion (the Fusion page in Resolve) and it doesn't seem to have a proper alpha channel in there either... I'll play with it some more but I think it's time I read the manual.

I haven't used these plugins, but it sounds like you need to add an alpha output to the clip's grade., and connect the alpha channel of the keyer node to it.

Tried that. I even worked entirely in the fusion page with a green screen clip and a background image. BCC Primatte Studio won't create an alpha channel.

BTW - I replaced the BCC Primatte Studio with Fusion's own Delta Keyer and everything worked perfectly so perhaps there is an issue with BCC (time to contact Boris).

Anyone know if this is a known issue with BCC in Resolve?

An update to this issue - contacted BorisFX and it sounds like something changed in Resolve 15.1 or 15.1.1 that has broken the ChromaKey Studio and Primatte Studio plugins.

To the OP - are you running Resolve 15.1.x or the original 15?

I wonder if BMD is aware of this?

Yes, I am running the latest version 15.1

I believe the Ignite Chroma and Luminance keys also suffer this same problem.

While BorisFX will probably look into this, I would suggest that we also raise this with BMD...

BMB Support got back to me with a workaround I have not yet tried:

AS a workaround, force the OFX to respect the background by enabling the Light Wrap and then setting the background to None. You can then disable the Light Wrap. Also, make sure you set the OFX node to use the OFX Alpha

Just an FYI - I gave the suggested workaround a try for both Chroma Key Studio and Primatte Studio and it works on both the color page and the fusion page but not on the edit page. In Primatte Studio when you enable light-wrap, the viewer indicates that light-wrap is not supported with this host but that doesn't matter - having light-wrap enabled allows you to change the background setting for the plugin from Source B to None as described by support. Then you can turn light-wrap off and you will see the expected alpha.