void gst_event_parse_caps (GstEvent *event, GstCaps **caps);
/* segment event */
-GstEvent* gst_event_new_segment (GstSegment *segment);
+GstEvent* gst_event_new_segment (const GstSegment *segment);
void gst_event_parse_segment (GstEvent *event, const GstSegment **segment);
void gst_event_copy_segment (GstEvent *event, GstSegment *segment);