<refentry id="vidioc-query-dv-preset"> <refmeta> <refentrytitle>ioctl VIDIOC_QUERY_DV_PRESET</refentrytitle> &manvol; </refmeta> <refnamediv> <refname>VIDIOC_QUERY_DV_PRESET</refname> <refpurpose>Sense the DV preset received by the current input</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcprototype> <funcdef>int <function>ioctl</function></funcdef> <paramdef>int <parameter>fd</parameter></paramdef> <paramdef>int <parameter>request</parameter></paramdef> <paramdef>&v4l2-dv-preset; *<parameter>argp</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Arguments</title> <variablelist> <varlistentry> <term><parameter>fd</parameter></term> <listitem> <para>&fd;</para> </listitem> </varlistentry> <varlistentry> <term><parameter>request</parameter></term> <listitem> <para>VIDIOC_QUERY_DV_PRESET</para> </listitem> </varlistentry> <varlistentry> <term><parameter>argp</parameter></term> <listitem> <para></para> </listitem> </varlistentry> </variablelist> </refsect1> <refsect1> <title>Description</title> <para>The hardware may be able to detect the current DV preset automatically, similar to sensing the video standard. To do so, applications call <constant> VIDIOC_QUERY_DV_PRESET</constant> with a pointer to a &v4l2-dv-preset; type. Once the hardware detects a preset, that preset is returned in the preset field of &v4l2-dv-preset;. When detection is not possible or fails, the value V4L2_DV_INVALID is returned.</para> </refsect1> <refsect1> &return-value; <variablelist> <varlistentry> <term><errorcode>EINVAL</errorcode></term> <listitem> <para>This ioctl is not supported.</para> </listitem> </varlistentry> <varlistentry> <term><errorcode>EBUSY</errorcode></term> <listitem> <para>The device is busy and therefore can not sense the preset</para> </listitem> </varlistentry> </variablelist> </refsect1> </refentry> <!-- Local Variables: mode: sgml sgml-parent-document: "v4l2.sgml" indent-tabs-mode: nil End: -->