Straighten video that isn't level

The below steps will allow you to straighten an IP camera feed which isn't level due to a dodgy sight screen, faulty equipment or poor setup of a camera kit. This can be fixed retrospectively or implemented live using OBS. 

To add an IP camera into OBS, follow the steps in the below video and then use the steps in the first video on the page to straighten the video feed. 

Example of this in practice below: