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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml b/Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml new file mode 100644 index 000000000..6e3cadd4e --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-enum-dv-timings.xml @@ -0,0 +1,133 @@ +<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> |