Add mac ffmpeg profile

[jburnhams]

Add ffmpeg profile for mac (testing on M1 macbook air)

Contributor Checklist

• [X] Review Contribution Guidelines
• [X] Agree to the terms of Developer Certificate of Origin.
• [X] Make sure all contributed code can be distributed under the terms of the GNU Licence
• [X] Check "Allow edit from maintainers" option in pull request so that additional changes can be pushed by maintainers if required.
• [ ] Unit tests created/updated (under tests) to verify logic, and approval tests for UI Widgets
• [ ] Update Examples - Under build-scripts/examples, and regenerate examples docs if required ( make doc-examples )
• [ ] Ensure that tests pass locally - this can be tricky for approval tests with maps or text though.
• [ ] Check that pre-release tests work ( make test-distribution )