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<table class="head">
<tr>
<td class="head-ltitle">UAUDIO(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">UAUDIO(4)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">uaudio</code> — <span class="Nd">USB audio
device driver</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">uaudio* at uhub?</code>
<br/>
<code class="Cd">audio* at audiobus?</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">uaudio</code> driver provides support for USB
audio class devices.</p>
<p class="Pp">A USB audio device consists of a number of components: input
terminals (e.g. USB digital input), output terminals (e.g. speakers), and a
number of units in between (e.g. volume control). The following types of
units are handled by the <code class="Nm">uaudio</code> driver and are
accessible via the mixer (see <a class="Xr">audio(4)</a>) interface:</p>
<dl class="Bl-tag">
<dt id="mixer"><a class="permalink" href="#mixer"><i class="Em">mixer</i></a></dt>
<dd>A mixer has a number of inputs and one output. Each input has a control
that determines its volume in the output. The name of the control is
<code class="Li">mix</code><var class="Ar">N</var><code class="Li">-</code><var class="Ar">S</var>,
where <var class="Ar">N</var> is a number that identifies which mixer it
is and <var class="Ar">S</var> which input.</dd>
<dt id="selector"><a class="permalink" href="#selector"><i class="Em">selector</i></a></dt>
<dd>A selector unit selects one of multiple audio sources such as mic-in and
line-in. The name of the control is
<code class="Li">sel</code><var class="Ar">N</var><code class="Li">-</code><var class="Ar">S1S2S3...</var>,
where <var class="Ar">N</var> is a number that identifies which selector
unit it is and the sequence of <var class="Ar">Sn</var> indicates
candidate units for the audio source.</dd>
<dt id="feature"><a class="permalink" href="#feature"><i class="Em">feature</i></a></dt>
<dd>A feature unit changes the sound in some way, like bass, treble, mute, or
volume. The name of the control is determined in a heuristic way. If the
unit changes the sound to a speaker output terminal, the names of the
controls may be <code class="Li">outputs.speaker.bass</code>,
<code class="Li">outputs.speaker.treble</code>,
<code class="Li">outputs.speaker.mute</code>,
<code class="Li">outputs.speaker</code>, or likewise.</dd>
<dt id="processing"><a class="permalink" href="#processing"><i class="Em">processing</i></a></dt>
<dd>A processing unit does one of a number of audio processing functions
(e.g., channel up-down mixing, Dolby ProLogic, or chorus effects). The
name of the on–off control is
<code class="Li">pro</code><var class="Ar">N</var><code class="Li">.</code><var class="Ar">M</var><code class="Li">-enable</code>,
where <var class="Ar">N</var> is a number that identifies which processing
unit it is and <var class="Ar">M</var> which kind. Depending on the type
of processing unit there may be other controls as well.</dd>
<dt id="extension"><a class="permalink" href="#extension"><i class="Em">extension</i></a></dt>
<dd>An extension unit performs some unspecified audio processing The name of
the on–off control is
<code class="Li">ext</code><var class="Ar">N</var><code class="Li">-enable</code>,
where <var class="Ar">N</var> is a number that identifies which processing
unit it is.</dd>
</dl>
<p class="Pp">For more information the USB Audio class specification is
indispensable reading.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">audio(4)</a>, <a class="Xr">usb(4)</a></p>
<p class="Pp"><cite class="Rs"><span class="RsT">USB Approved Class
Specification Documents</span>,
<a class="RsU" href="http://www.usb.org/developers/docs/devclass_docs/">http://www.usb.org/developers/docs/devclass_docs/</a>.</cite></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">uaudio</code> driver appeared in
<span class="Ux">NetBSD 1.5</span>. Support for USB Audio Class 2.0 devices
appeared in <span class="Ux">NetBSD 11.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1>
<p class="Pp">There is no support for multiple-endpoints audio stream, adaptive
recording, async playback, and TYPE-II/III formats.</p>
<p class="Pp">There is the possibility that a device has multiple mixer items
which have the same name.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">May 21, 2024</td>
<td class="foot-os">NetBSD 10.1</td>
</tr>
</table>
|
