I am facing a peculiar problem. We have made a custom video display using ADV7401 as one of the component. The video inputs are STANAG A/ STANAG B. I have tested the display in house with our source it works fine. But when I took the unit to the site and tested with the client's source it was flickering very much. So I reduced the gain settings in the ADV 7401 then the flickering reduced. And I was able to get rid of the flickering in STANAG B by changing the register 0x8D value from 0x83 to 0x03. Then I changed the gain setting from manual to auto in this mode(STANAG B). So STANAG B has a stable picture and good brightness . .So But the other video is still disturbed once in a while. Also the gain setting is so low that it cannot be accepted. Can you please tell me what could be the possible reason for this behavior? And is there a way to fix the issue without reducing the gain.
Note: The video inputs are RGB component with sync on green. Taken in on YPbPr. Also I have noted one more thing that is at the actual gain settings when the picture flickers if I remove connection to either to R or B then the flickering stops.