Windows display set to 1280x720, looks like 1280x720, but is 1920x1080?

Note, this is not about vMix's external display, but feeding vMix from external PCs.

We often produce in HD (1280x720 at 50p) and sometimes source inputs from external PCs via HDMI. In order to offload the production PC we have typically set the output from the external PC to match our production settings. In other words, in Windows on the external PC we set its external display resolution to 1280x720, and if possible to 50p.

Earlier we have noticed that even if we set the PC to display 1280x720, it seems to output 1920x1080 when we check on an external monitors display information (ie using the monitors menu system). vMix also suggest 1920x1080 if the external PC is used to source an Input card (eg Yuan). Using the Input's Advanced tab to find out what the card gets, says the same. Nevertheless, the actual results looks like 1280x720 (eg a window moved the from a laptops built in display at 1920x1080 grows when dragged to its external display set to the lower resolution).

Now, with Windows 10 this "is 1280 looks 720" seems to be the case on all of our "external" PCs.

Anyone who knows more about this behaviour and can explain what is going on?

On events we usually use scalers do make sure that whatever is input to the scaler (eg from a presenters Windows/OSX laptop) is scaled to what we want. But within our own production setup, and in our studio, it would be nice to skip the scalers.

Thanks ovinas, but that does not help. And on some PCs the Intel HD Graphics control panel is not available.

Rather seems to be the case of an unclear and complicated EDID handshaking between Windows and the display.

Lesson learned is that what you set is not always what you get ;)