MP4GetSampleTime - Get the start time of a track sample
hFile Specifies the mp4 file to which the operation applies.
Specifies the track to which the operation applies.
Specifies the sample to which the operation applies. Caveat: the
first sample has id 1 not 0.
Upon success, the sample start time in track time scale units. Upon an
MP4GetSampleTime returns the start time of the specified sample from
the specified track in the track time scale units. See
MP4ConvertFromTrackTimestamp() for how to map this value to another