1<refentry id="vidioc-query-dv-preset"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_QUERY_DV_PRESET</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_QUERY_DV_PRESET</refname> 9 <refpurpose>Sense the DV preset 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-dv-preset; *<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_QUERY_DV_PRESET</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 DV preset 53automatically, similar to sensing the video standard. To do so, applications 54call <constant> VIDIOC_QUERY_DV_PRESET</constant> with a pointer to a 55&v4l2-dv-preset; type. Once the hardware detects a preset, that preset is 56returned in the preset field of &v4l2-dv-preset;. If the preset could not be 57detected because there was no signal, or the signal was unreliable, or the 58signal did not map to a supported preset, then the value V4L2_DV_INVALID is 59returned.</para> 60 </refsect1> 61 62 <refsect1> 63 &return-value; 64 <variablelist> 65 <varlistentry> 66 <term><errorcode>EINVAL</errorcode></term> 67 <listitem> 68 <para>This ioctl is not supported.</para> 69 </listitem> 70 </varlistentry> 71 <varlistentry> 72 <term><errorcode>EBUSY</errorcode></term> 73 <listitem> 74 <para>The device is busy and therefore can not sense the preset</para> 75 </listitem> 76 </varlistentry> 77 </variablelist> 78 </refsect1> 79</refentry> 80 81<!-- 82Local Variables: 83mode: sgml 84sgml-parent-document: "v4l2.sgml" 85indent-tabs-mode: nil 86End: 87--> 88