<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry></entry>
- <entry>Type of the event.</entry>
+ <entry>Type of the event, see <xref linkend="event-type" />.</entry>
</row>
<row>
<entry>union</entry>
</tgroup>
</table>
+ <table frame="none" pgwide="1" id="event-type">
+ <title>Event Types</title>
+ <tgroup cols="3">
+ &cs-def;
+ <tbody valign="top">
+ <row>
+ <entry><constant>V4L2_EVENT_ALL</constant></entry>
+ <entry>0</entry>
+ <entry>All events. V4L2_EVENT_ALL is valid only for
+ VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once.
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_VSYNC</constant></entry>
+ <entry>1</entry>
+ <entry>This event is triggered on the vertical sync.
+ This event has a &v4l2-event-vsync; associated with it.
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_EOS</constant></entry>
+ <entry>2</entry>
+ <entry>This event is triggered when the end of a stream is reached.
+ This is typically used with MPEG decoders to report to the application
+ when the last of the MPEG stream has been decoded.
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_CTRL</constant></entry>
+ <entry>3</entry>
+ <entry><para>This event requires that the <structfield>id</structfield>
+ matches the control ID from which you want to receive events.
+ This event is triggered if the control's value changes, if a
+ button control is pressed or if the control's flags change.
+ This event has a &v4l2-event-ctrl; associated with it. This struct
+ contains much of the same information as &v4l2-queryctrl; and
+ &v4l2-control;.</para>
+
+ <para>If the event is generated due to a call to &VIDIOC-S-CTRL; or
+ &VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to
+ the file handle that called the ioctl function. This prevents
+ nasty feedback loops. If you <emphasis>do</emphasis> want to get the
+ event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant>
+ flag.
+ </para>
+
+ <para>This event type will ensure that no information is lost when
+ more events are raised than there is room internally. In that
+ case the &v4l2-event-ctrl; of the second-oldest event is kept,
+ but the <structfield>changes</structfield> field of the
+ second-oldest event is ORed with the <structfield>changes</structfield>
+ field of the oldest event.</para>
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry>
+ <entry>4</entry>
+ <entry>
+ <para>Triggered immediately when the reception of a
+ frame has begun. This event has a
+ &v4l2-event-frame-sync; associated with it.</para>
+
+ <para>If the hardware needs to be stopped in the case of a
+ buffer underrun it might not be able to generate this event.
+ In such cases the <structfield>frame_sequence</structfield>
+ field in &v4l2-event-frame-sync; will not be incremented. This
+ causes two consecutive frame sequence numbers to have n times
+ frame interval in between them.</para>
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_SOURCE_CHANGE</constant></entry>
+ <entry>5</entry>
+ <entry>
+ <para>This event is triggered when a source parameter change is
+ detected during runtime by the video device. It can be a
+ runtime resolution change triggered by a video decoder or the
+ format change happening on an input connector.
+ This event requires that the <structfield>id</structfield>
+ matches the input index (when used with a video device node)
+ or the pad index (when used with a subdevice node) from which
+ you want to receive events.</para>
+
+ <para>This event has a &v4l2-event-src-change; associated
+ with it. The <structfield>changes</structfield> bitfield denotes
+ what has changed for the subscribed pad. If multiple events
+ occurred before application could dequeue them, then the changes
+ will have the ORed value of all the events generated.</para>
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_MOTION_DET</constant></entry>
+ <entry>6</entry>
+ <entry>
+ <para>Triggered whenever the motion detection state for one or more of the regions
+ changes. This event has a &v4l2-event-motion-det; associated with it.</para>
+ </entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
+ <entry>0x08000000</entry>
+ <entry>Base event number for driver-private events.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
<table frame="none" pgwide="1" id="v4l2-event-vsync">
<title>struct <structname>v4l2_event_vsync</structname></title>
<tgroup cols="3">
<entry>__u32</entry>
<entry><structfield>changes</structfield></entry>
<entry></entry>
- <entry>A bitmask that tells what has changed. See <xref linkend="changes-flags" />.</entry>
+ <entry>A bitmask that tells what has changed. See <xref linkend="ctrl-changes-flags" />.</entry>
</row>
<row>
<entry>__u32</entry>
</tgroup>
</table>
- <table pgwide="1" frame="none" id="changes-flags">
- <title>Changes</title>
+ <table pgwide="1" frame="none" id="ctrl-changes-flags">
+ <title>Control Changes</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
- <entry>Type of the event.</entry>
+ <entry>Type of the event, see <xref linkend="event-type" />. Note that
+<constant>V4L2_EVENT_ALL</constant> can be used with VIDIOC_UNSUBSCRIBE_EVENT
+for unsubscribing all events at once.</entry>
</row>
<row>
<entry>__u32</entry>
</tgroup>
</table>
- <table frame="none" pgwide="1" id="event-type">
- <title>Event Types</title>
- <tgroup cols="3">
- &cs-def;
- <tbody valign="top">
- <row>
- <entry><constant>V4L2_EVENT_ALL</constant></entry>
- <entry>0</entry>
- <entry>All events. V4L2_EVENT_ALL is valid only for
- VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once.
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_VSYNC</constant></entry>
- <entry>1</entry>
- <entry>This event is triggered on the vertical sync.
- This event has a &v4l2-event-vsync; associated with it.
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_EOS</constant></entry>
- <entry>2</entry>
- <entry>This event is triggered when the end of a stream is reached.
- This is typically used with MPEG decoders to report to the application
- when the last of the MPEG stream has been decoded.
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_CTRL</constant></entry>
- <entry>3</entry>
- <entry><para>This event requires that the <structfield>id</structfield>
- matches the control ID from which you want to receive events.
- This event is triggered if the control's value changes, if a
- button control is pressed or if the control's flags change.
- This event has a &v4l2-event-ctrl; associated with it. This struct
- contains much of the same information as &v4l2-queryctrl; and
- &v4l2-control;.</para>
-
- <para>If the event is generated due to a call to &VIDIOC-S-CTRL; or
- &VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to
- the file handle that called the ioctl function. This prevents
- nasty feedback loops. If you <emphasis>do</emphasis> want to get the
- event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant>
- flag.
- </para>
-
- <para>This event type will ensure that no information is lost when
- more events are raised than there is room internally. In that
- case the &v4l2-event-ctrl; of the second-oldest event is kept,
- but the <structfield>changes</structfield> field of the
- second-oldest event is ORed with the <structfield>changes</structfield>
- field of the oldest event.</para>
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry>
- <entry>4</entry>
- <entry>
- <para>Triggered immediately when the reception of a
- frame has begun. This event has a
- &v4l2-event-frame-sync; associated with it.</para>
-
- <para>If the hardware needs to be stopped in the case of a
- buffer underrun it might not be able to generate this event.
- In such cases the <structfield>frame_sequence</structfield>
- field in &v4l2-event-frame-sync; will not be incremented. This
- causes two consecutive frame sequence numbers to have n times
- frame interval in between them.</para>
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_SOURCE_CHANGE</constant></entry>
- <entry>5</entry>
- <entry>
- <para>This event is triggered when a source parameter change is
- detected during runtime by the video device. It can be a
- runtime resolution change triggered by a video decoder or the
- format change happening on an input connector.
- This event requires that the <structfield>id</structfield>
- matches the input index (when used with a video device node)
- or the pad index (when used with a subdevice node) from which
- you want to receive events.</para>
-
- <para>This event has a &v4l2-event-src-change; associated
- with it. The <structfield>changes</structfield> bitfield denotes
- what has changed for the subscribed pad. If multiple events
- occurred before application could dequeue them, then the changes
- will have the ORed value of all the events generated.</para>
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_MOTION_DET</constant></entry>
- <entry>6</entry>
- <entry>
- <para>Triggered whenever the motion detection state for one or more of the regions
- changes. This event has a &v4l2-event-motion-det; associated with it.</para>
- </entry>
- </row>
- <row>
- <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
- <entry>0x08000000</entry>
- <entry>Base event number for driver-private events.</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
-
<table pgwide="1" frame="none" id="event-flags">
<title>Event Flags</title>
<tgroup cols="3">
OSDN Git Service
