typedef union {
        int type;
        XvVideoNotifyEvent xvvideo;
        XvPortNotifyEvent xvport;
        long pad[24];
      } XvEvent;
      typedef struct {
        int type;
        unsigned long serial;
        Bool send_event;
        Display *display;
        XvPortID port_id;
        Time time;
        Atom attribute;
        long value;
      } XvPortNotifyEvent;
Specifies the type of event: XvPortNotify.
Number of the last request processed by the server.
True if the event was generated by a SendEvent request.
A pointer to the display the event was read from.
The port whose attribute has changed.
An atom specifying the attribute that changed.
The new value of the attribute.