Documentation/DocBook/v4l/vidioc-overlay.xml

   1 <refentry id="vidioc-overlay">
   2   <refmeta>
   3     <refentrytitle>ioctl VIDIOC_OVERLAY</refentrytitle>
   4     &manvol;
   5   </refmeta>
   6
   7   <refnamediv>
   8     <refname>VIDIOC_OVERLAY</refname>
   9     <refpurpose>Start or stop video overlay</refpurpose>
  10   </refnamediv>
  11
  12   <refsynopsisdiv>
  13     <funcsynopsis>
  14       <funcprototype>
  15         <funcdef>int <function>ioctl</function></funcdef>
  16         <paramdef>int <parameter>fd</parameter></paramdef>
  17         <paramdef>int <parameter>request</parameter></paramdef>
  18         <paramdef>const int *<parameter>argp</parameter></paramdef>
  19       </funcprototype>
  20     </funcsynopsis>
  21   </refsynopsisdiv>
  22
  23   <refsect1>
  24     <title>Arguments</title>
  25
  26     <variablelist>
  27       <varlistentry>
  28         <term><parameter>fd</parameter></term>
  29         <listitem>
  30           <para>&fd;</para>
  31         </listitem>
  32       </varlistentry>
  33       <varlistentry>
  34         <term><parameter>request</parameter></term>
  35         <listitem>
  36           <para>VIDIOC_OVERLAY</para>
  37         </listitem>
  38       </varlistentry>
  39       <varlistentry>
  40         <term><parameter>argp</parameter></term>
  41         <listitem>
  42           <para></para>
  43         </listitem>
  44       </varlistentry>
  45     </variablelist>
  46   </refsect1>
  47
  48   <refsect1>
  49     <title>Description</title>
  50
  51     <para>This ioctl is part of the <link linkend="overlay">video
  52     overlay</link> I/O method. Applications call
  53     <constant>VIDIOC_OVERLAY</constant> to start or stop the
  54     overlay. It takes a pointer to an integer which must be set to
  55     zero by the application to stop overlay, to one to start.</para>
  56
  57     <para>Drivers do not support &VIDIOC-STREAMON; or
  58 &VIDIOC-STREAMOFF; with <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>.</para>
  59   </refsect1>
  60
  61   <refsect1>
  62     &return-value;
  63
  64     <variablelist>
  65       <varlistentry>
  66         <term><errorcode>EINVAL</errorcode></term>
  67         <listitem>
  68           <para>Video overlay is not supported, or the
  69 parameters have not been set up. See <xref
  70 linkend="overlay" /> for the necessary steps.</para>
  71         </listitem>
  72       </varlistentry>
  73     </variablelist>
  74   </refsect1>
  75 </refentry>
  76
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