getPresentationStartTimeAsDate() {
    if (this.manifest_ && !this.isRemotePlayback()) {
      const timeline = this.manifest_.presentationTimeline;
      const startTime = timeline.getInitialProgramDateTime() ||
          timeline.getPresentationStartTime();
      goog.asserts.assert(startTime != null,
          'Presentation start time should not be null!');
      return new Date(/* ms= */ startTime * 1000);
    } else if (this.video_ && this.video_.getStartDate) {
      // Apple's native HLS gives us getStartDate(), which is only available if
      // EXT-X-PROGRAM-DATETIME is in the playlist.
      const startDate = this.video_.getStartDate();
      if (isNaN(startDate.getTime())) {
        shaka.log.warning(
            'EXT-X-PROGRAM-DATETIME required to get presentation start time ' +
            'as Date!');
        return null;
      }
      return startDate;
    } else {
      shaka.log.warning('No way to get presentation start time as Date!');
      return null;
    }
  }
Get the presentation start time as a date.

@return {Date}
@export