Quote ... I thought I could create a PNG mask of the speaker, invert the mask, and then use Chroma Key to greenscreen the background. I'm having problems.

Please give recommendations.

Thanks very much for including the video you're working with. I'm afraid you've got quite a bit of work here because the background is fairly close to the skin color of the speaker, and also because it's a handheld video with some unwanted motion.

I spent a few minutes on this using only the basic PD17 tools, and the first thing I did was to stabilize the video so there's less motion overall. The next thing I did was to stack two copies of the clip and create an oval mask for the speaker's face on the track 2 clip. On the underlying (track 1) clip, I used 3 chroma keys to take out as many shades of the background as possible.

That has to be done with a mask letting her face come through from the overlay, because the chroma keying would also take out lots of flesh as well

The next step is to use keyframes to adjust the mask to only allow her face and neck through as she tilts and gestures. You'll need to adjust the position, scale and rotation since her hair is straight and lies very close to her face. Here's what the first 12 seconds look like, and you can see a couple spots where the mask overshoots and undershoots the areas you'll eventually want protected:



I've packed the project in this OneDrive folder, so feel free to start working with it and tweak it as needed.

You may also want to do this in stages, like producing the stabilized clip first to reduce the workload for the other edits. You can also do more chroma keying in stages, producing each one and building up to a perfectly empty background.

Once that's done, you can simply CK on the black in the final clip and place whatever bacground you want behind the speaker and you'll be all set!

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Here is 10 seconds of it. ColorDirector with the latest updates crashed so I renoved the 7 seconds where the hand is moved over the face and redid it.