Using green screen with zoomed out / cropped footage

Hi all

I am running DR15 on a PC and can successfully use the alpha channel to remove the green background to display footage behind the foreground object. However... this only works for me when the foreground footage is used at 100% zoom or larger. As soon as I zoom out on the foreground footage the area that is outside the footage turns black. I can see the background footage through the reduced foreground footage, but not anything else.

I have seriously been looking all over to the try find the solution, but to no avail. I also tried using the Delta-key in fusion, but the effect is the same. And I don't understand the signal flow... why would zoomed out footage affect the whole of the screen and not just its reduced display area? Makes no sense to me.

I need this because I want to remove the green screen from a "talking head" that is zoomed out and placed in the bottom right corner whilst training material is being displayed in the background.

I have included two images as example, one where their is no background removal on the foreground footage and one where there is (leaving the rest of the screen black).

Help would be much appreciated. Thanks!

In Fusion, create a garbage matte that covers the rest of the screen that is showing up black and connect it to the garbage matte input on the Delta Keyer node.

Thanks Eric. Definitely going to try that this weekend.

I guess there is no way to apply garbage matte in a similar way via the colour page? It always seem to be more efficient to use the colour page rather than fusion.

Anyway, appreciate the advice.

When using the qualifier key on the colour page, if you use node sizing instead of edit sizing you don't need a mask or garbage matte.

Try making a slight change in the inspector crop setting of the foreground clip.

Thanks Eric. Definitely going to try that this weekend.

I guess there is no way to apply garbage matte in a similar way via the colour page? It always seem to be more efficient to use the colour page rather than fusion.

Anyway, appreciate the advice.

You can also use a Power Window and a qualifier under the Color tab for the greenscreen and for the video in the corner.

When using the qualifier key on the colour page, if you use node sizing instead of edit sizing you don't need a mask or garbage matte.

Good alternative.

When keying in Fusion, add a size transform node after the Delta keyer to position and scale. No more black border!

All these workarounds kind of work - but I'd like to be able to make the background on zoomed out clips transparent - or at least, for that to be an option. Power windows work but when animated a green screen object, it just becomes painful. If we could select 'transparent background' (also when using crops it should be an option!) life would be better