Fix video overlay video colours

[gavinhenderson]

Is your feature request related to a problem? Please describe.
Its not obvious that the red and green eye indicate different eyes. A red outline would usually indicate an error but doesn't in this case

Describe the solution you'd like
Make the colours more sensible and less ambiguous

Describe alternatives you've considered
We could just generally improve the video overlay to make it more user friendly

Additional context
Add any other context or screenshots about the feature request here.