Tiny osd (max7456

bought one of these:

https://www.tinyosshop.com/arduino-osd-shield
used the library associated with it and included that on the complier side of things.

I am trying to get it to display on a 5.8" NTSC 400*234 screen with a camera as a video input source.

using the example sketches I can't seem to get any thing to show.
Video Time Inserter is the test case
MEGA 2560 is the unit I am using and the sketch complies but doesn't seem to display.
using the current arduino version (1.8.16)

ideas?