iuVCR keyboard shortcuts:

Main window

Shortcut Action
F1 Call this reference
F12 Shapshot
PageDown Next channel
PageUp Previous channel
Numpad1-Numpad9 Channels 1-9
Space Preview toggle
Ctrl-Space Start recording
Shift-Space Stop recording
M Mute toggle

Preview window

Preview window passthrough shortcuts for main window and also have some own keyboard combinations:

Shortcut Action
Ctrl-S Always on top toggle
Ctrl-A Keep ratio toggle
Ctrl-F1 1:2 window scale
Ctrl-F2 1:1 window scale
Ctrl-F3 2:1 window scale
Alt-Enter Full screen toggle