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 83<!-- 84Local Variables: 85mode: sgml 86sgml-parent-document: "v4l2.sgml" 87indent-tabs-mode: nil 88End: 89--> 90