The OWL Compositing Toolkit includes an input pass for Screen Capture which ensure that your media input is perfectly synced with your other Comp layers. 

1. Select the Comp layer you want to stream into (for example your Media Plate) and in the Details panel go to Composure> Input> add Input> in the MediaSource drop down select OWLScreen Capture Input Pass:
2. Open the 'Receiver' section and you can configure your Screen Capture:
   1. Screen Capture Type lets you choose between Monitor (full screen)and Window Capture (individual programs):
   2. Window/ Monitor Name let's you choose between different Monitors or Windows you have open on your machine:
   3. You can also Enable/ Disable the capture and choose to select your Cursor:
3. Now you will instantly see your selected Monitor/ Window appear in your Media Plate (or whatever Composure layer you have created the Input for):