mirror of https://gitee.com/openkylin/linux.git
99 lines
3.1 KiB
XML
99 lines
3.1 KiB
XML
<refentry id="vidioc-g-std">
|
|
<refmeta>
|
|
<refentrytitle>ioctl VIDIOC_G_STD, VIDIOC_S_STD</refentrytitle>
|
|
&manvol;
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>VIDIOC_G_STD</refname>
|
|
<refname>VIDIOC_S_STD</refname>
|
|
<refpurpose>Query or select the video standard of 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_std_id
|
|
*<parameter>argp</parameter></paramdef>
|
|
</funcprototype>
|
|
</funcsynopsis>
|
|
<funcsynopsis>
|
|
<funcprototype>
|
|
<funcdef>int <function>ioctl</function></funcdef>
|
|
<paramdef>int <parameter>fd</parameter></paramdef>
|
|
<paramdef>int <parameter>request</parameter></paramdef>
|
|
<paramdef>const v4l2_std_id
|
|
*<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_G_STD, VIDIOC_S_STD</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><parameter>argp</parameter></term>
|
|
<listitem>
|
|
<para></para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para>To query and select the current video standard applications
|
|
use the <constant>VIDIOC_G_STD</constant> and <constant>VIDIOC_S_STD</constant> ioctls which take a pointer to a
|
|
&v4l2-std-id; type as argument. <constant>VIDIOC_G_STD</constant> can
|
|
return a single flag or a set of flags as in &v4l2-standard; field
|
|
<structfield>id</structfield>. The flags must be unambiguous such
|
|
that they appear in only one enumerated <structname>v4l2_standard</structname> structure.</para>
|
|
|
|
<para><constant>VIDIOC_S_STD</constant> accepts one or more
|
|
flags, being a write-only ioctl it does not return the actual new standard as
|
|
<constant>VIDIOC_G_STD</constant> does. When no flags are given or
|
|
the current input does not support the requested standard the driver
|
|
returns an &EINVAL;. When the standard set is ambiguous drivers may
|
|
return <errorcode>EINVAL</errorcode> or choose any of the requested
|
|
standards. If the current input or output does not support standard video timings (e.g. if
|
|
&VIDIOC-ENUMINPUT; does not set the <constant>V4L2_IN_CAP_STD</constant> flag), then
|
|
&ENODATA; is returned.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
&return-value;
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><errorcode>EINVAL</errorcode></term>
|
|
<listitem>
|
|
<para>The <constant>VIDIOC_S_STD</constant> parameter was unsuitable.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorcode>ENODATA</errorcode></term>
|
|
<listitem>
|
|
<para>Standard video timings are not supported for this input or output.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
</refentry>
|