FrameRate
format->u.encoded_video.output.field_rate = FrameRate();
double frameRate = FrameRate();
double frameRate = FrameRate();
*frame = int64_t(*time * FrameRate() / 1000000.0 + 0.5);
double FrameRate() const;
double frameRate = FrameRate();
float frameRate = FrameRate();
float FrameRate() const;