MP4ConvertFromTrackTimestamp - Man Page
Convert a timestamp from the track time scale to a specified time scale.
Specifies the mp4 file to which the operation applies.
Specifies the track from which the timestamp originates.
Specifies the timestamp that is to be converted.
Specifies the new time scale in ticks per second to which the timestamp should be converted.
Upon success, the timestamp in the new time scale units. Upon error, 0xFFFFFFFFFFFFFFFF.
MP4ConvertFromTrackTimestamp converts a timestamp such as a sample start time from the track time scale to another specified time scale. This can be used by a player application to map all track samples to a common time scale.