virtual RESULT getLength(pts_t &pts) = 0;
virtual RESULT getCurrentPosition(pts_t &pos) = 0;
virtual RESULT seekTo(pts_t &pts) = 0;
virtual RESULT getLength(pts_t &pts) = 0;
virtual RESULT getCurrentPosition(pts_t &pos) = 0;
virtual RESULT seekTo(pts_t &pts) = 0;