obs-outputs: Allow enabling BPM for Hybrid MP4 output

[derrod]

Description

Adds an option to enable BPM (Broadcast Performance Metrics) for the Hybrid MP4 output.

Motivation and Context

BPM is quite useful to track performance over time, having it in a local file is a nice debugging option.

How Has This Been Tested?

Enabled it and checked BPM data is in output file.

Types of changes

• New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[Lain-B]

Seems fine, but what exactly made you think of doing this? Did something happen?

[derrod]

Seems fine, but what exactly made you think of doing this? Did something happen?

I just wanted to be able to get BPM data without needing to have a streaming output with it enabled. I also wanted to add this to the debug output option we have for multitrack so local files also include this info.