Is it possible to apply chroma key to only a certain area using a mask or some other method? The box to change from fullscreen to masked area only doesn't appear under chroma key- only color, distortion, etc.
If you are, in addition, using a mask are you wanting to see some of the green screen rather than the background or do you want to remove say one of the people from the foreground? If the latter you can do this:
A second copy of the background is placed in front (lower track) and a black and white mask is inserted and given 'alpha' chroma key. Where the mask is white you see what is in front (the copy of the background). Where the mask is black you see whatever is in back (your original people with green screen + background pair).
For a still image I could paint out the woman with green but that would be difficult to do with a video clip!
If you are, in addition, using a mask are you wanting to see some of the green screen rather than the background or do you want to remove say one of the people from the foreground? If the latter you can do this:
A second copy of the background is placed in front (lower track) and a black and white mask is inserted and given 'alpha' chroma key. Where the mask is white you see what is in front (the copy of the background). Where the mask is black you see whatever is in back (your original people with green screen + background pair).
For a still image I could paint out the woman with green but that would be difficult to do with a video clip!