I have seen a few YouTube videos about this little device. It is an adapter board that plugs into the original Denise chip socket on the Amiga 500 and then has a raspberry pi zero connected into it. This then allows the Digital RGB signal directly from the Amiga to be output via the HDMI of the pi giving a pixel perfect digital output.
The actual RGBtoHDMI project was originally designed for the BBC Micro but has since been adapted to work with many other retro systems. The Amiga version requires an adapter board designed by C0pperdragon and can be found here.
The adapter boards are available for purchase but the waiting list is apparently quite long so I decided to get the bare PCBs ordered from JLPCB and ordered the components from various places and then built my own over the weekend. Suprisingly it worked first time!
The only issue with using it on an Amiga is that it doesn’t output the audio, so you either need to connect the audio up to an amp via phono cables or get a device to inject the phono audio into the HDMI signal. I have ordered one of these from China so will test it when it gets here to see how well that works.