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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. When detection is not
58possible or fails, the set must contain all standards supported by the
59current video input or output.</para>
60
61 </refsect1>
62
63 <refsect1>
64 &return-value;
65
66 <variablelist>
67 <varlistentry>
68 <term><errorcode>EINVAL</errorcode></term>
69 <listitem>
70 <para>This ioctl is not supported.</para>
71 </listitem>
72 </varlistentry>
73 <varlistentry>
74 <term><errorcode>EBUSY</errorcode></term>
75 <listitem>
76 <para>The device is busy and therefore can not detect the standard</para>
77 </listitem>
78 </varlistentry>
79 </variablelist>
80 </refsect1>
81</refentry>
82
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