Function CMTimebaseCreateWithMasterTimebase 

pub unsafe fn CMTimebaseCreateWithMasterTimebase(
    allocator: CFAllocatorRef,
    masterTimebase: CMTimebaseRef,
    timebaseOut: *mut CMTimebaseRef,
) -> OSStatus

Creates a timebase using another timebase as its master. Wraps CMTimebaseCreateWithMasterTimebase.

Safety

timebaseOut must be writable, and every supplied Core Media reference must be valid for the duration of the call.