+ * for video. 1/time_base is not the average frame rate if the frame rate is not
+ * constant.
+ *
+ * Like containers, elementary streams also can store timestamps, 1/time_base
+ * is the unit in which these timestamps are specified.
+ * As example of such codec time base see ISO/IEC 14496-2:2001(E)
+ * vop_time_increment_resolution and fixed_vop_rate
+ * (fixed_vop_rate == 0 implies that it is different from the framerate)
+ *