This page guides you on how to add a custom mode to the VNC viewer.
Here is an example of a custom mode being provided by Adder support.
In VNC Viewer, navigate to Controls -> Video Settings -> Custom Mode.
First, input resolution and refresh rate, and click Calc.
Next, click Edit to input other parameters and click OK.
Finally, click Save or add another custom mode by repeating the two steps above.
This page is related to Collecting timing details.