CurrentTime property of VideoReader object

The VideoReader object mentions that its property CurrentTime gives the timestamp for each frame in seconds from the start of the video file.

Query:

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Statement (A) : It is not mentioned if this is the way MATLAB predicts it by using the average frame rate value and then using the average time difference between consecutive frames to generate this timestamp? (Average time difference = 1 / Average frame rate)

OR

Statement (B) : Is the timestamp given by CurrentTime the actual position in time of the specific frame when the video was recorded?

I need to confirm this beacause I need to extract timestamped video frames and the time has to be the one recorded when the frame was captured. I do have the start and stop time of the video. But as a camera can never provide the exact frame rate, I cannot depend on merely using the formula to calculate the timestamps based on the start/stop times. If Statement (B) is true, I can use the timestamps provided by MATLAB to calculate when the corresponding frames were captured by adding this time to the video start time.

Any help will be appreciated.