blob: 222348542182bfb06b5019bbac2ea023d06bab02 [file] [log] [blame]
Mauro Carvalho Chehab8e080c2e2009-09-13 22:16:04 -03001<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
Hans Verkuilf41c4332013-05-29 10:19:05 -030057distinguish between 50 and 60 Hz systems. If no signal was detected,
58then the driver will return V4L2_STD_UNKNOWN. When detection is not
Mauro Carvalho Chehab8e080c2e2009-09-13 22:16:04 -030059possible 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;
Hans Verkuil663dc7f2012-09-14 06:44:20 -030066 <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>
Mauro Carvalho Chehab8e080c2e2009-09-13 22:16:04 -030074 </refsect1>
75</refentry>