Based on kernel version 3.0.4. Page generated on 2011-10-03 22:07 EST.
1 <refentry id="vidioc-g-audioout"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_G_AUDOUT</refname> 9 <refname>VIDIOC_S_AUDOUT</refname> 10 <refpurpose>Query or select the current audio output</refpurpose> 11 </refnamediv> 12 13 <refsynopsisdiv> 14 <funcsynopsis> 15 <funcprototype> 16 <funcdef>int <function>ioctl</function></funcdef> 17 <paramdef>int <parameter>fd</parameter></paramdef> 18 <paramdef>int <parameter>request</parameter></paramdef> 19 <paramdef>struct v4l2_audioout *<parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 <funcsynopsis> 23 <funcprototype> 24 <funcdef>int <function>ioctl</function></funcdef> 25 <paramdef>int <parameter>fd</parameter></paramdef> 26 <paramdef>int <parameter>request</parameter></paramdef> 27 <paramdef>const struct v4l2_audioout *<parameter>argp</parameter></paramdef> 28 </funcprototype> 29 </funcsynopsis> 30 </refsynopsisdiv> 31 32 <refsect1> 33 <title>Arguments</title> 34 35 <variablelist> 36 <varlistentry> 37 <term><parameter>fd</parameter></term> 38 <listitem> 39 <para>&fd;</para> 40 </listitem> 41 </varlistentry> 42 <varlistentry> 43 <term><parameter>request</parameter></term> 44 <listitem> 45 <para>VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</para> 46 </listitem> 47 </varlistentry> 48 <varlistentry> 49 <term><parameter>argp</parameter></term> 50 <listitem> 51 <para></para> 52 </listitem> 53 </varlistentry> 54 </variablelist> 55 </refsect1> 56 57 <refsect1> 58 <title>Description</title> 59 60 <para>To query the current audio output applications zero out the 61 <structfield>reserved</structfield> array of a &v4l2-audioout; and 62 call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer 63 to this structure. Drivers fill the rest of the structure or return an 64 &EINVAL; when the device has no audio inputs, or none which combine 65 with the current video output.</para> 66 67 <para>Audio outputs have no writable properties. Nevertheless, to 68 select the current audio output applications can initialize the 69 <structfield>index</structfield> field and 70 <structfield>reserved</structfield> array (which in the future may 71 contain writable properties) of a 72 <structname>v4l2_audioout</structname> structure and call the 73 <constant>VIDIOC_S_AUDOUT</constant> ioctl. Drivers switch to the 74 requested output or return the &EINVAL; when the index is out of 75 bounds. This is a write-only ioctl, it does not return the current 76 audio output attributes as <constant>VIDIOC_G_AUDOUT</constant> 77 does.</para> 78 79 <para>Note connectors on a TV card to loop back the received audio 80 signal to a sound card are not audio outputs in this sense.</para> 81 82 <table pgwide="1" frame="none" id="v4l2-audioout"> 83 <title>struct <structname>v4l2_audioout</structname></title> 84 <tgroup cols="3"> 85 &cs-str; 86 <tbody valign="top"> 87 <row> 88 <entry>__u32</entry> 89 <entry><structfield>index</structfield></entry> 90 <entry>Identifies the audio output, set by the 91 driver or application.</entry> 92 </row> 93 <row> 94 <entry>__u8</entry> 95 <entry><structfield>name</structfield>[32]</entry> 96 <entry>Name of the audio output, a NUL-terminated ASCII 97 string, for example: "Line Out". This information is intended for the 98 user, preferably the connector label on the device itself.</entry> 99 </row> 100 <row> 101 <entry>__u32</entry> 102 <entry><structfield>capability</structfield></entry> 103 <entry>Audio capability flags, none defined yet. Drivers 104 must set this field to zero.</entry> 105 </row> 106 <row> 107 <entry>__u32</entry> 108 <entry><structfield>mode</structfield></entry> 109 <entry>Audio mode, none defined yet. Drivers and 110 applications (on <constant>VIDIOC_S_AUDOUT</constant>) must set this 111 field to zero.</entry> 112 </row> 113 <row> 114 <entry>__u32</entry> 115 <entry><structfield>reserved</structfield>[2]</entry> 116 <entry>Reserved for future extensions. Drivers and 117 applications must set the array to zero.</entry> 118 </row> 119 </tbody> 120 </tgroup> 121 </table> 122 </refsect1> 123 124 <refsect1> 125 &return-value; 126 127 <variablelist> 128 <varlistentry> 129 <term><errorcode>EINVAL</errorcode></term> 130 <listitem> 131 <para>No audio outputs combine with the current video 132 output, or the number of the selected audio output is out of bounds or 133 it does not combine, or there are no audio outputs at all and the 134 ioctl is not supported.</para> 135 </listitem> 136 </varlistentry> 137 <varlistentry> 138 <term><errorcode>EBUSY</errorcode></term> 139 <listitem> 140 <para>I/O is in progress, the output cannot be 141 switched.</para> 142 </listitem> 143 </varlistentry> 144 </variablelist> 145 </refsect1> 146 </refentry> 147 148 <!-- 149 Local Variables: 150 mode: sgml 151 sgml-parent-document: "v4l2.sgml" 152 indent-tabs-mode: nil 153 End: 154 -->
