I used a XC9572 Xilinx cpld because it is easy to solder, 5V tolerant, cheap and available.
For composite video I used the AD724 ic. There is a jtag connector to program the cpld on board.
To build this project one needs a programmer for the xilinx cpld.
It takes power from the Aplle IIc so there is no need for external power supply.
I tested the last version of the pcb and everything works ok, I use PCBWay to make the pcbs.
My friend Akis Fletsios made a 3d printed case.
Hardware design and software released under the Creative Commons License BY-NC-SA