Running the VideoFrameCapture.pde sketch works great with the Output Select switch in “Overlay” mode. But switching it to “Sync Only” gives no output instead of the 1-bit image.
Am I missing something obvious? Moving the jumper seems to have no effect on the output signal.
Yes, the potentiometer with the long stem. It is for adjusting the threshold.
The input signal is the same, but when connected to the TV, there is 75 ohms of resistance between signal and ground in the TV, so when you disconnect the TV (with the switch set to sync only), it changes the electrical characteristics.