Function frame_rate_from_info 

pub fn frame_rate_from_info(info: &FrameRateInfo) -> FrameRate

Reconstruct a FrameRate enum from a FrameRateInfo embedded in a Timecode.

This is a best-effort reconstruction: it cannot distinguish e.g. Fps23976 from Fps24 (both have nominal fps=24) without the drop-frame flag, so it uses the drop-frame flag and nominal fps to select the most common matching variant.