/** The video frame rate that this content is or was prepared to be used with,
* or empty if the effective rate of this content should be dictated by something
* else (either some video happening at the same time, or the rate of the DCP).
/** The video frame rate that this content is or was prepared to be used with,
* or empty if the effective rate of this content should be dictated by something
* else (either some video happening at the same time, or the rate of the DCP).