media/v4l/vidioc-subscribe-event.xml

1 <refentry id="vidioc-subscribe-event">
53     dequeued by using the &VIDIOC-DQEVENT; ioctl.</para>
55     <table frame="none" pgwide="1" id="v4l2-event-subscription">
58 	&cs-str;
68 	    <entry>ID of the event source. If there is no ID associated with
75 	    <entry>Event flags, see <xref linkend="event-flags" />.</entry>
87     <table frame="none" pgwide="1" id="event-type">
90 	&cs-def;
95 	    <entry>All events. V4L2_EVENT_ALL is valid only for
102 	    <entry>This event is triggered on the vertical sync.
103 	    This event has a &v4l2-event-vsync; associated with it.
109 	    <entry>This event is triggered when the end of a stream is reached.
110 	    This is typically used with MPEG decoders to report to the application
111 	    when the last of the MPEG stream has been decoded.
119 		This event is triggered if the control's value changes, if a
120 		button control is pressed or if the control's flags change.
121 	    	This event has a &v4l2-event-ctrl; associated with it. This struct
122 		contains much of the same information as &v4l2-queryctrl; and
123 		&v4l2-control;.</para>
125 		<para>If the event is generated due to a call to &VIDIOC-S-CTRL; or
126 		&VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to
133 		<para>This event type will ensure that no information is lost when
134 		more events are raised than there is room internally. In that
135 		case the &v4l2-event-ctrl; of the second-oldest event is kept,
137 		second-oldest event is ORed with the <structfield>changes</structfield>
147 	      &v4l2-event-frame-sync; associated with it.</para>
152 	      field in &v4l2-event-frame-sync; will not be incremented. This
160 	    <entry>Base event number for driver-private events.</entry>
166     <table pgwide="1" frame="none" id="event-flags">
169 	&cs-def;
174 	    <entry>When this event is subscribed an initial event will be sent
184 		&VIDIOC-S-CTRL; will cause a V4L2_EVENT_CTRL to be sent back to that same
191 		or by the &VIDIOC-S-CTRL; call it is hard to decide whether to set the
204     &return-value;