You can find the schematic and board design files for the Video Experimenter’s Board at https://github.com/Batperson/video_experimenters_board. Files are in KiCad format and gerber format. The VEB is basically a stripped-down version of the ADV7184 evaluation board.
The source code for the Weka OSD proof of concept is at https://github.com/Batperson/weka_osd.
Weka OSD 