If no video and/or audio is rendered from a (supported) Blackmagic device, try one or more of the following:
- Change the output settings of your camera, then those of the Blackmagic to match.
- Close any other open program which is retrieving data from the capture card.
- Reconnect the cables on the Blackmagic.
- Restart your encoding software.
- Powercycle the Blackmagic.
- Restart your PC/Mac.