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Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-g-audioout.xml')
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diff --git a/Documentation/DocBook/v4l/vidioc-g-audioout.xml b/Documentation/DocBook/v4l/vidioc-g-audioout.xml new file mode 100644 index 0000000..3632730 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-g-audioout.xml @@ -0,0 +1,154 @@ +<refentry id="vidioc-g-audioout"> + <refmeta> + <refentrytitle>ioctl VIDIOC_G_AUDOUT, VIDIOC_S_AUDOUT</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_G_AUDOUT</refname> + <refname>VIDIOC_S_AUDOUT</refname> + <refpurpose>Query or select the current audio output</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_audioout *<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 struct v4l2_audioout *<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_AUDOUT, VIDIOC_S_AUDOUT</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <para>To query the current audio output applications zero out the +<structfield>reserved</structfield> array of a &v4l2-audioout; and +call the <constant>VIDIOC_G_AUDOUT</constant> ioctl with a pointer +to this structure. Drivers fill the rest of the structure or return an +&EINVAL; when the device has no audio inputs, or none which combine +with the current video output.</para> + + <para>Audio outputs have no writable properties. Nevertheless, to +select the current audio output applications can initialize the +<structfield>index</structfield> field and +<structfield>reserved</structfield> array (which in the future may +contain writable properties) of a +<structname>v4l2_audioout</structname> structure and call the +<constant>VIDIOC_S_AUDOUT</constant> ioctl. Drivers switch to the +requested output or return the &EINVAL; when the index is out of +bounds. This is a write-only ioctl, it does not return the current +audio output attributes as <constant>VIDIOC_G_AUDOUT</constant> +does.</para> + + <para>Note connectors on a TV card to loop back the received audio +signal to a sound card are not audio outputs in this sense.</para> + + <table pgwide="1" frame="none" id="v4l2-audioout"> + <title>struct <structname>v4l2_audioout</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Identifies the audio output, set by the +driver or application.</entry> + </row> + <row> + <entry>__u8</entry> + <entry><structfield>name</structfield>[32]</entry> + <entry>Name of the audio output, a NUL-terminated ASCII +string, for example: "Line Out". This information is intended for the +user, preferably the connector label on the device itself.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>capability</structfield></entry> + <entry>Audio capability flags, none defined yet. Drivers +must set this field to zero.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>mode</structfield></entry> + <entry>Audio mode, none defined yet. Drivers and +applications (on <constant>VIDIOC_S_AUDOUT</constant>) 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> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>No audio outputs combine with the current video +output, or the number of the selected audio output is out of bounds or +it does not combine, or there are no audio outputs at all and the +ioctl is not supported.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>EBUSY</errorcode></term> + <listitem> + <para>I/O is in progress, the output cannot be +switched.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> + +<!-- +Local Variables: +mode: sgml +sgml-parent-document: "v4l2.sgml" +indent-tabs-mode: nil +End: +--> |
