mac-virtualcam: Correct device timer firing rate

[jcm93]

Description

Resolves the conversion to a Double in OBSCameraDeviceSource, such that the virtual camera device timer fires correctly every 1/60 seconds, instead of trying to fire every 0 seconds.

Motivation and Context

Resolves #9760. CPU use was very high with the new virtual camera extension at idle and while active because of the amount of polling the device timer was doing.

How Has This Been Tested?

Tested locally on my machine. Reduced camera extension process CPU use by roughly 10x.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

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.

[PatTheMav]

That was indeed my mistake, the original example code correctly uses 1.0 / Double(kFrameRate) as the loop interval.

[felippenardi]

@PatTheMav Do you happen to know when a new release candidate with this fix is going to be published? I'd like to try it

[PatTheMav]

It's a critical fix, so we'll probably try to get it in as soon as possible.