Improvement: Add support for FX-DIRECT video for HDMI scalers

[raymondh2]

Details below of implementation below. This would allow 4K HDMI scalers like the Morph 4K to receive the native resolution in a padded HDMI frame
https://docs.pixelfx.co/VSIF-metadata-FX-direct.html
https://gitlab.com/pixelfx-public/fx-direct