Looks like Mike Chi’s RetroTINK-2X uses a PIC controlled ADV7280 with ADV7513 HDMI transmitter.
The ADV7280 has a TON of options but Mikes PIC controlled design has only two buttons to disable “ANTIALIASING FILTERS” and switch (mux) inputs, all else at default.
The chip itself can do Contrast, Brightness, Hue, Saturation, Test Patterns, C/Y Filtering, DNR, and a LOT more advanced parameters.
The output is 8bit YCbCr 4:2:2 (ITU-R BT.656), but it’s well beyond good enough for Composite and S-Video.
Hopefully his product will be reasonably priced (around 65$) like his other RetroTINK designs.