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- <refentry id="vidioc-enum-dv-timings">
- <refmeta>
- <refentrytitle>ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS</refentrytitle>
- &manvol;
- </refmeta>
- <refnamediv>
- <refname>VIDIOC_ENUM_DV_TIMINGS</refname>
- <refname>VIDIOC_SUBDEV_ENUM_DV_TIMINGS</refname>
- <refpurpose>Enumerate supported Digital Video timings</refpurpose>
- </refnamediv>
- <refsynopsisdiv>
- <funcsynopsis>
- <funcprototype>
- <funcdef>int <function>ioctl</function></funcdef>
- <paramdef>int <parameter>fd</parameter></paramdef>
- <paramdef>int <parameter>request</parameter></paramdef>
- <paramdef>struct v4l2_enum_dv_timings *<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_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><parameter>argp</parameter></term>
- <listitem>
- <para></para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
- <refsect1>
- <title>Description</title>
- <note>
- <title>Experimental</title>
- <para>This is an <link linkend="experimental"> experimental </link>
- interface and may change in the future.</para>
- </note>
- <para>While some DV receivers or transmitters support a wide range of timings, others
- support only a limited number of timings. With this ioctl applications can enumerate a list
- of known supported timings. Call &VIDIOC-DV-TIMINGS-CAP; to check if it also supports other
- standards or even custom timings that are not in this list.</para>
- <para>To query the available timings, applications initialize the
- <structfield>index</structfield> field and zero the reserved array of &v4l2-enum-dv-timings;
- and call the <constant>VIDIOC_ENUM_DV_TIMINGS</constant> ioctl on a video node with a
- pointer to this structure. Drivers fill the rest of the structure or return an
- &EINVAL; when the index is out of bounds. To enumerate all supported DV timings,
- applications shall begin at index zero, incrementing by one until the
- driver returns <errorcode>EINVAL</errorcode>. Note that drivers may enumerate a
- different set of DV timings after switching the video input or
- output.</para>
- <para>When implemented by the driver DV timings of subdevices can be queried
- by calling the <constant>VIDIOC_SUBDEV_ENUM_DV_TIMINGS</constant> ioctl directly
- on a subdevice node. The DV timings are specific to inputs (for DV receivers) or
- outputs (for DV transmitters), applications must specify the desired pad number
- in the &v4l2-enum-dv-timings; <structfield>pad</structfield> field. Attempts to
- enumerate timings on a pad that doesn't support them will return an &EINVAL;.</para>
- <table pgwide="1" frame="none" id="v4l2-enum-dv-timings">
- <title>struct <structname>v4l2_enum_dv_timings</structname></title>
- <tgroup cols="3">
- &cs-str;
- <tbody valign="top">
- <row>
- <entry>__u32</entry>
- <entry><structfield>index</structfield></entry>
- <entry>Number of the DV timings, set by the
- application.</entry>
- </row>
- <row>
- <entry>__u32</entry>
- <entry><structfield>pad</structfield></entry>
- <entry>Pad number as reported by the media controller API. This field
- is only used when operating on a subdevice node. When operating on a
- video node applications must set this field to zero.</entry>
- </row>
- <row>
- <entry>__u32</entry>
- <entry><structfield>reserved</structfield>[2]</entry>
- <entry>Reserved for future extensions. Drivers and applications must
- set the array to zero.</entry>
- </row>
- <row>
- <entry>&v4l2-dv-timings;</entry>
- <entry><structfield>timings</structfield></entry>
- <entry>The timings.</entry>
- </row>
- </tbody>
- </tgroup>
- </table>
- </refsect1>
- <refsect1>
- &return-value;
- <variablelist>
- <varlistentry>
- <term><errorcode>EINVAL</errorcode></term>
- <listitem>
- <para>The &v4l2-enum-dv-timings; <structfield>index</structfield>
- is out of bounds or the <structfield>pad</structfield> number is invalid.</para>
- </listitem>
- </varlistentry>
- <varlistentry>
- <term><errorcode>ENODATA</errorcode></term>
- <listitem>
- <para>Digital video presets are not supported for this input or output.</para>
- </listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
- </refentry>
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