PTZ cameras can be controlled by assigning a PTZ shortcut to an input where PTZ has been configured.
For example the shortcut "PTZMoveUp" once activated will keep the camera moving upward until a corresponding "PTZMoveStop" shortcut is activated.
For more information on the shortcuts available see Shortcut Function Reference
vMix includes a shortcut template that assigns PTZ control to joysticks and buttons on a USB XBOX controller
By default this template assigns all the buttons to the Preview input which means as long as a PTZ enabled camera is in input it can be moved and controlled using this template.
Of course, the shortcuts in this template can be edited to assign to a particular input if you prefer.
By default, PTZ shortcuts will use the speeds defined by the sliders in the Input Settings PTZ tab.
To specify a custom speed, specify a fractional number between 0 and 1 as the Value of the shortcut.
To enable variable speeds on pressure sensitive controllers (such as joysticks and the XBOX controller), from shortcuts tick the Pressure Enabled checkbox
for all applicable shortcuts.