Can these adapters not do more than 480p? I made one with a board the video chip on it is MS1820. The datasheet for that chip says
Supports 720P, 1080I, 1080P HD input
Supports HD1080I to1080P conversion
So surely it should work at resolutions more than 480p? if i have other res enabled I will only see bios then get a black screen after. Video output is also quite dark compared to component. Audio from the hdmi port is terrible also but sounds great through the headphone jack