1<refentry id="vidioc-querystd">
2  <refmeta>
3    <refentrytitle>ioctl VIDIOC_QUERYSTD</refentrytitle>
4    &manvol;
5  </refmeta>
6
7  <refnamediv>
8    <refname>VIDIOC_QUERYSTD</refname>
9    <refpurpose>Sense the video standard received by the current
10input</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>v4l2_std_id *<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_QUERYSTD</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    <para>The hardware may be able to detect the current video
53standard automatically. To do so, applications call <constant>
54VIDIOC_QUERYSTD</constant> with a pointer to a &v4l2-std-id; type. The
55driver stores here a set of candidates, this can be a single flag or a
56set of supported standards if for example the hardware can only
57distinguish between 50 and 60 Hz systems. If no signal was detected,
58then the driver will return V4L2_STD_UNKNOWN. When detection is not
59possible or fails, the set must contain all standards supported by the
60current video input or output.</para>
61
62  </refsect1>
63
64  <refsect1>
65    &return-value;
66    <variablelist>
67      <varlistentry>
68	<term><errorcode>ENODATA</errorcode></term>
69	<listitem>
70	  <para>Standard video timings are not supported for this input or output.</para>
71	</listitem>
72      </varlistentry>
73    </variablelist>
74  </refsect1>
75</refentry>
76