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<concept id="GUID-D62A282E-9DEA-5EF3-A606-20647BC5049D" xml:lang="en"><title>Audio Client Overview </title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>This document provides an overview of the Audio Client. </p>
<section id="GUID-DBB3FA4E-B6E7-4545-8C15-F58DE69780DA"><title>Purpose</title> <p>The Audio Client provides an interface
to: </p> <ul>
<li id="GUID-E1752C25-893D-5859-A9B7-C527AC115044"><p>Play back, record,
and convert sound clips. </p> </li>
<li id="GUID-5AF02D1B-25A9-59F0-B57B-7F0CAE7EB07D"><p>Play tone sequences
and DTMF (Dual-Tone Multi-Frequency) strings. </p> </li>
</ul> <p><b>Audio Client Library Details</b> </p> <p>The DLL that provides
the functionality and the library to which your code must link is
identified below. </p> <table id="GUID-28BCAB7A-147C-5519-8833-62ACA430C4D3">
<tgroup cols="3"><colspec colname="col0"/><colspec colname="col1"/>
<colspec colname="col2"/>
<thead>
<row>
<entry>DLL</entry>
<entry>LIB</entry>
<entry>Short Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><p> <b>mediaclientaudio.dll</b>  </p> </entry>
<entry><p> <b>mediaclientaudio.lib</b>  </p> </entry>
<entry><p>These files are used for implementing the Audio Client. </p> </entry>
</row>
</tbody>
</tgroup>
</table> </section>
<section id="GUID-24255721-6198-4D8A-A560-DC86C14E92A7"><title>Architectural Relationship</title> <p>The methods
for recording, converting, and playing audio clips or tones interact
with the lower levels of MMF (known as the controller framework).
The controller framework is in turn responsible for managing the interface
to audio hardware. On some phones, this is implemented as a device
driver; on others it may be implemented as a connection to a lower
level hardware controller. </p> <p>Clients using any of the <xref href="GUID-29FB1DE6-D00C-3E6B-A8AA-476FAFD7F26C.dita"><apiname>CMdaAudioRecorderUtility</apiname></xref>, <xref href="GUID-810D29DA-8332-3E63-8A63-5B8A04EC9688.dita"><apiname>CMdaAudioConvertUtility</apiname></xref>, <xref href="GUID-778D24B5-A68E-3C91-B66A-69007FBA4791.dita"><apiname>CMdaAudioPlayerUtility</apiname></xref> or <xref href="GUID-D728A286-A202-3915-9643-8FD70646F78A.dita"><apiname>CMdaAudioToneUtility</apiname></xref> classes must have an active scheduler running in their thread because
the implementations use active objects and callbacks. </p> <p>How
the tone player class interacts with other components of MMF is shown
below. </p> <fig id="GUID-8273BE86-D5F9-528F-9147-0C0C58D9ABCD">
<title>              Audio tone player overview            </title>
<image href="GUID-4F879832-8425-5C56-B3FE-4C4592EBB6A5_d0e313397_href.png" placement="inline"/>
</fig> </section>
<section id="GUID-B41E6DF0-5963-4AF8-822E-473380A1CE78"><title>Description</title> <p><b>Audio Playing, Recording, and Conversion</b> </p> <p>All three
of the audio classes are plugin based, leaving the list of supported
audio formats for input and output open ended. The audio file formats
supported as standard by MMF are: AU, WAV and raw audio data. Each
file format may support one or more compression algorithms (codecs).
The standard file formats and corresponding codecs are shown below: </p> <table id="GUID-058548B8-0DEF-5E61-B9A1-6FEC07DCAA8A">
<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
<thead>
<row>
<entry>Audio file format</entry>
<entry>Codecs supported</entry>
</row>
</thead>
<tbody>
<row>
<entry><p>AU </p> </entry>
<entry><p>A-Law, mu-law, signed 16 bit PCM big-endian, signed 8 bit
PCM </p> </entry>
</row>
<row>
<entry><p>WAV </p> </entry>
<entry><p>IMA-ADPCM, A-Law, mu-law, unsigned 8 bit PCM, gsm 6.10,
signed 16 bit PCM </p> </entry>
</row>
<row>
<entry><p>raw data </p> </entry>
<entry><p>Signed big-endian 16 bit PCM, signed 16 bit PCM, unsigned
16 bit PCM </p> </entry>
</row>
</tbody>
</tgroup>
</table> <p>Input and output audio data can be of any format supported
by the installed plugins. When possible MMF uses a plugin resolver
to determine the format and codecs to use. It determines this by checking
the filename extension and reading any header data that may be present
in the audio clip. The plugin resolver cannot determine the format
and codecs to use for raw audio, so in such cases you must specify
this information yourself. A full list of supported plugins can be
retrieved by using <xref href="GUID-810D29DA-8332-3E63-8A63-5B8A04EC9688.dita#GUID-810D29DA-8332-3E63-8A63-5B8A04EC9688/GUID-D0456E01-109E-3C93-949D-0452B09E886F"><apiname>CMdaAudioConvertUtility::GetSupportedDestinationDataTypesL()</apiname></xref>. </p> <p> <b> Note:</b> All audio clips can be uniquely identified
for purposes of plugin assignment by their format (gsm z6.10, AU,
WAV and so on) and their codec (for example for AU, valid codecs include
A-Law, mu-law, signed 16 bit PCM big-endian, signed 8 bit PCM). Each
format and codec has an arbitrary ID assigned to it by MMF and its
associated plugin, for use with the "Open" functions of both <codeph>CMdaAudioConvertUtility</codeph> and <codeph>CMdaAudioRecorderUtility</codeph>. </p> <p id="GUID-B99776D8-B713-5C18-AB32-3BF13EDDFEBB"><b>Tone Playing</b> </p> <p>The Audio Client provide a simple interface for tone generation
(synthesized sounds) that enables the playing of tone sequences and
DTMF (Dual-Tone Multi-Frequency) strings. The tone player functionality
is provided by the <xref href="GUID-D728A286-A202-3915-9643-8FD70646F78A.dita"><apiname>CMdaAudioToneUtility</apiname></xref> class and
using this class you can play: </p> <ul>
<li id="GUID-5B1FD304-5905-5F3A-97C6-237A59F911A1"><p>Single tones
of a specified duration and frequency. </p> </li>
<li id="GUID-6CD5A5D6-8659-5DDB-B773-1513C663E4F6"><p>DTMF strings. </p> </li>
<li id="GUID-9F98BD96-C5F6-5100-96FB-EA8396AE0364"><p>Sequences of
tones held in files or descriptors. </p> </li>
<li id="GUID-B27D9870-E9AE-5280-A144-E4C24AA91E09"><p>Predefined (fixed)
sequences of tones held in the mobile equipment. </p> </li>
</ul> </section>
<section id="GUID-7655A8EA-ADE9-4CDE-95D9-27055E14122D"><title>Key Audio Client Classes</title> <p>The functionality
provided by the Audio Client is contained within the following classes: </p> <ul>
<li id="GUID-0EF967E4-CFE1-5528-9EAB-BA0A2E71C6D3"><p> <xref href="GUID-29FB1DE6-D00C-3E6B-A8AA-476FAFD7F26C.dita"><apiname>CMdaAudioRecorderUtility</apiname></xref>  </p> </li>
<li id="GUID-93D94E92-E9E6-523B-9C4B-02DF91D9976E"><p> <xref href="GUID-810D29DA-8332-3E63-8A63-5B8A04EC9688.dita"><apiname>CMdaAudioConvertUtility</apiname></xref>  </p> </li>
<li id="GUID-CBD9AF2F-BB55-5D03-A87B-A7A23AAA4CD5"><p> <xref href="GUID-778D24B5-A68E-3C91-B66A-69007FBA4791.dita"><apiname>CMdaAudioPlayerUtility</apiname></xref>  </p> </li>
<li id="GUID-3B16D9CB-B192-548F-B096-5BA7B0E89344"><p> <xref href="GUID-D728A286-A202-3915-9643-8FD70646F78A.dita"><apiname>CMdaAudioToneUtility</apiname></xref> <xref href="GUID-6BD89347-671F-3518-9777-55801A090C79.dita"><apiname/></xref>  </p> </li>
</ul> </section>
<section id="GUID-CD24BD19-FCE1-4F3E-8E1D-906FC63AD238"><title>Using the Audio Client</title> <p>Clients can use
the Audio Client to: </p> <ul>
<li id="GUID-AB6FC77A-FD23-55F0-9A07-916D388CE19D"><p>Manipulate audio
sources and sinks, add, retrieve and modify meta data and record audio
data to files or descriptors. </p> </li>
<li id="GUID-8557E211-D6E7-59FF-AE63-939A0BCBF3C4"><p>Convert audio
clips contained in files or descriptors to other formats using the
default codecs provided by MMF. </p> </li>
<li id="GUID-E9D2FB84-0CF1-5873-BC5B-005869025A91"><p>Play audio clips
contained in files, descriptors or URLs. </p> </li>
<li id="GUID-C3C75693-4113-5684-9643-2C6DC1A5BCB0"><p>Play single
tones, DTMF strings and tone sequences. </p> </li>
</ul> </section>
<section id="GUID-04F7EA21-F6B4-4C37-A37E-F86B3C94FCD3"><title>See Also</title> <p><xref href="GUID-F46E4F89-B9ED-5A4A-B812-B605B925D0C0.dita">How to use the audio
convert utility</xref>  </p> <p><xref href="GUID-9EE78D5A-32BC-5E0F-9139-AF00CDB95CC1.dita">How to use the audio
tone player utility</xref>  </p> <p><xref href="GUID-2D3F7471-9B92-5E49-B8BC-E0FA7AA709D7.dita">DevSound Overview</xref>  </p> </section>
</conbody></concept>