About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / DocBook / media / v4l / vidioc-enum-dv-timings.xml




Custom Search

Based on kernel version 3.16. Page generated on 2014-08-06 21:39 EST.

1	<refentry id="vidioc-enum-dv-timings">
2	  <refmeta>
3	    <refentrytitle>ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS</refentrytitle>
4	    &manvol;
5	  </refmeta>
6	
7	  <refnamediv>
8	    <refname>VIDIOC_ENUM_DV_TIMINGS</refname>
9	    <refname>VIDIOC_SUBDEV_ENUM_DV_TIMINGS</refname>
10	    <refpurpose>Enumerate supported Digital Video timings</refpurpose>
11	  </refnamediv>
12	
13	  <refsynopsisdiv>
14	    <funcsynopsis>
15	      <funcprototype>
16		<funcdef>int <function>ioctl</function></funcdef>
17		<paramdef>int <parameter>fd</parameter></paramdef>
18		<paramdef>int <parameter>request</parameter></paramdef>
19		<paramdef>struct v4l2_enum_dv_timings *<parameter>argp</parameter></paramdef>
20	      </funcprototype>
21	    </funcsynopsis>
22	  </refsynopsisdiv>
23	
24	  <refsect1>
25	    <title>Arguments</title>
26	
27	    <variablelist>
28	      <varlistentry>
29		<term><parameter>fd</parameter></term>
30		<listitem>
31		  <para>&fd;</para>
32		</listitem>
33	      </varlistentry>
34	      <varlistentry>
35		<term><parameter>request</parameter></term>
36		<listitem>
37		  <para>VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS</para>
38		</listitem>
39	      </varlistentry>
40	      <varlistentry>
41		<term><parameter>argp</parameter></term>
42		<listitem>
43		  <para></para>
44		</listitem>
45	      </varlistentry>
46	    </variablelist>
47	  </refsect1>
48	
49	  <refsect1>
50	    <title>Description</title>
51	
52	    <note>
53	      <title>Experimental</title>
54	      <para>This is an <link linkend="experimental"> experimental </link>
55	      interface and may change in the future.</para>
56	    </note>
57	
58	    <para>While some DV receivers or transmitters support a wide range of timings, others
59	support only a limited number of timings. With this ioctl applications can enumerate a list
60	of known supported timings. Call &VIDIOC-DV-TIMINGS-CAP; to check if it also supports other
61	standards or even custom timings that are not in this list.</para>
62	
63	    <para>To query the available timings, applications initialize the
64	<structfield>index</structfield> field and zero the reserved array of &v4l2-enum-dv-timings;
65	and call the <constant>VIDIOC_ENUM_DV_TIMINGS</constant> ioctl on a video node with a
66	pointer to this structure. Drivers fill the rest of the structure or return an
67	&EINVAL; when the index is out of bounds. To enumerate all supported DV timings,
68	applications shall begin at index zero, incrementing by one until the
69	driver returns <errorcode>EINVAL</errorcode>. Note that drivers may enumerate a
70	different set of DV timings after switching the video input or
71	output.</para>
72	
73	    <para>When implemented by the driver DV timings of subdevices can be queried
74	by calling the <constant>VIDIOC_SUBDEV_ENUM_DV_TIMINGS</constant> ioctl directly
75	on a subdevice node. The DV timings are specific to inputs (for DV receivers) or
76	outputs (for DV transmitters), applications must specify the desired pad number
77	in the &v4l2-enum-dv-timings; <structfield>pad</structfield> field. Attempts to
78	enumerate timings on a pad that doesn't support them will return an &EINVAL;.</para>
79	
80	    <table pgwide="1" frame="none" id="v4l2-enum-dv-timings">
81	      <title>struct <structname>v4l2_enum_dv_timings</structname></title>
82	      <tgroup cols="3">
83		&cs-str;
84		<tbody valign="top">
85		  <row>
86		    <entry>__u32</entry>
87		    <entry><structfield>index</structfield></entry>
88		    <entry>Number of the DV timings, set by the
89	application.</entry>
90		  </row>
91		  <row>
92		    <entry>__u32</entry>
93		    <entry><structfield>pad</structfield></entry>
94		    <entry>Pad number as reported by the media controller API. This field
95		    is only used when operating on a subdevice node. When operating on a
96		    video node applications must set this field to zero.</entry>
97		  </row>
98		  <row>
99		    <entry>__u32</entry>
100		    <entry><structfield>reserved</structfield>[2]</entry>
101		    <entry>Reserved for future extensions. Drivers and applications must
102		    set the array to zero.</entry>
103		  </row>
104		  <row>
105		    <entry>&v4l2-dv-timings;</entry>
106		    <entry><structfield>timings</structfield></entry>
107		    <entry>The timings.</entry>
108		  </row>
109		</tbody>
110	      </tgroup>
111	    </table>
112	  </refsect1>
113	
114	  <refsect1>
115	    &return-value;
116	
117	    <variablelist>
118	      <varlistentry>
119		<term><errorcode>EINVAL</errorcode></term>
120		<listitem>
121		  <para>The &v4l2-enum-dv-timings; <structfield>index</structfield>
122	is out of bounds or the <structfield>pad</structfield> number is invalid.</para>
123		</listitem>
124	      </varlistentry>
125	      <varlistentry>
126		<term><errorcode>ENODATA</errorcode></term>
127		<listitem>
128		  <para>Digital video presets are not supported for this input or output.</para>
129		</listitem>
130	      </varlistentry>
131	    </variablelist>
132	  </refsect1>
133	</refentry>
134	
135	<!--
136	Local Variables:
137	mode: sgml
138	sgml-parent-document: "v4l2.sgml"
139	indent-tabs-mode: nil
140	End:
141	-->
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.