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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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