<article lang="&language;" id="audiocd">
<title>audiocd</title>
<articleinfo>
<authorgroup>
<author><firstname>Rik</firstname><surname>Hemsley</surname>
<affiliation><address><email>rik@kde.org</email></address></affiliation>
</author>
</authorgroup>

<date>2001-07-14</date>
<releaseinfo>2.20.00</releaseinfo>

</articleinfo>

<para>Allows treating audio <acronym>CD</acronym>s like a
<quote>real</quote> filesystem, where tracks are represented as files
and, when copied from the directory, are digitally extracted from the
<acronym>CD</acronym>. This ensures a perfect copy of the audio
data.</para>

<para>To see how this slave works, insert an audio <acronym>CD</acronym>
in your &CD-ROM; drive and type <userinput>audiocd:/</userinput> into
&konqueror;. Within a few seconds you should see a list of tracks and
some directories.</para>

<para>Audio <acronym>CD</acronym>s don't really have directories, but
the audiocd slave provides them as a convenience. If you look inside
these directories you will see that they all contain the same number of
tracks. If you are connected to the Internet, some directories will have
the actual track titles shown as the filenames.</para>

<para>The reason that these separate directories exist are so that you
can choose in which format you would like to listen to (or copy) the
tracks on the <acronym>CD</acronym>.</para>

<para>If you drag a track from the <filename class="directory">Ogg
Vorbis</filename> directory and drop it on another &konqueror; window
open at your home directory, you should see a progress window showing
you that the track is being extracted from the <acronym>CD</acronym> and
saved to a file. Note that Ogg Vorbis is a compressed format, so the
file in your home directory will appear a great deal smaller than it
would have been if you had copied the raw data.</para>

<para>The mechanism behind this is quite simple. When the audiocd slave
is asked to retrieve a track from the <filename class="directory">Ogg
Vorbis</filename> directory, it starts extracting the digital audio data
from the <acronym>CD</acronym>. As it sends the data over to the file in
your home directory, it simultaneously encodes it in Ogg Vorbis format
(<acronym>CD</acronym> audio isn't in any particular format to start
with, it's just raw binary data.)</para>

<para>You could also try dragging a file ending in <literal
role="extension">.wav</literal> and dropping it on the &kde; Media
Player, &noatun;. In this case, the procedure that happens behind the
scenes is similar, except that instead of encoding the audio data in Ogg
Vorbis format, it is put through a very simple conversion, from raw
binary data (which the <literal role="extension">.cda</literal> files in
the toplevel directory represent) to <quote>RIFF WAV</quote> format, a
non-compressed format that most media players understand.</para>

<para>&noatun; should quite happily play the <literal
role="extension">.wav</literal> file, but if it has trouble, you may
consider using the <option>paranoia_level</option> option, explained
below.</para>

<variablelist>
<title>Options</title>
<varlistentry>
<term><option>device</option></term>
<listitem>
<para>Set the path to the audio <acronym>CD</acronym> device, e.g.
<userinput>audiocd:/<option>?device</option>=<parameter>/dev/sdc</parameter></userinput>.
Normally, the slave will try to find a <acronym>CD</acronym> drive with
an audio <acronym>CD</acronym> inserted, but if it fails or you have
more than one <acronym>CD</acronym> drive, you may want to try this
option. Note that the configuration dialog allows you to set a default
value for this option.</para>
</listitem>
</varlistentry>

<varlistentry>
<term><option>paranoia_level</option></term>
<listitem>
<para>Set the amount of error detection and correction used when
extracting data.</para>

<variablelist>
<varlistentry>
<term>Level 0</term>
<listitem>
<para>No detection or correction. Only useful if you have a perfect
<acronym>CD</acronym> drive (unlikely).</para>
</listitem>
</varlistentry>

<varlistentry>
<term>Level 1</term>
<listitem>
<para>Enable basic error checking and correction.</para>
</listitem>
</varlistentry>

<varlistentry>
<term>Level 2</term>
<listitem>
<para>Default.  Specifies that only a perfect extraction will be
accepted.</para>
</listitem>
</varlistentry>
</variablelist>

<para>Note that there is a disadvantage to level 2. Extraction can be
very slow, so real-time digital playback may not work properly. If you
have a good quality <acronym>CD</acronym> drive (note that more
expensive does not necessarily mean better quality) then you probably
won't experience very slow extraction, but a poor drive may take days
(!) to extract the audio from one <acronym>CD</acronym>.</para>
</listitem>
</varlistentry>

<varlistentry>
<term><option>use_cddb</option></term>
<listitem>

<para>Specify that track names for the inserted <acronym>CD</acronym>
will be looked up on the Internet <acronym>CD</acronym> Database. Audio
<acronym>CD</acronym>s don't have track names, but the Internet
<acronym>CD</acronym> Database is a clever system which uses a special
unique identifier generated from the number and length of tracks on each
<acronym>CD</acronym> to cross-reference a track listing. Track listings
are contributed by the Internet community and made available to
all.</para>

<para>You can submit your own track listings using &kscd;, the &kde;
<acronym>CD</acronym> player.</para>

<para>This option is on by default. If your Internet connection is not
set up correctly, you may find that your <acronym>CD</acronym> tracks
don't appear.  In this case, you can try
<userinput>audiocd:/?<option>use_cddb</option>=<parameter>0</parameter></userinput>
to switch this option off.</para>
</listitem>
</varlistentry>

<varlistentry>
<term><option>cddb_server</option></term>
<listitem>
<para>Set the Internet <acronym>CD</acronym> Database server to
contact. By default, this is
<systemitem>freedb.freedb.org:888</systemitem>, which means server
<systemitem>freedb.freedb.org</systemitem> at port 888.</para>
</listitem>
</varlistentry>
</variablelist>

<variablelist>
<title>Examples</title>
<varlistentry>
<term><userinput>audiocd:/?device=/dev/scd0?paranoia_level=0&amp;use_cddb=0</userinput></term>
<listitem>
<para>Gives a listing of the tracks on the audio <acronym>CD</acronym>
inserted in <filename class="devicefile">/dev/scd0</filename>, which on
&Linux; specifies the first <acronym>SCSI</acronym> &CD-ROM; device. If
you copy tracks from the <acronym>CD</acronym>, digital extraction will
be performed without error correction or detection. No Internet
<acronym>CD</acronym> Database will be contacted.</para>
</listitem>
</varlistentry>
</variablelist>

<qandaset>
<title>Frequently Asked Question</title>
<qandaentry>
<question>
<para>I get <errorname>The file or directory / does not
exist</errorname>.  How do I fix that? I have an audio
<acronym>CD</acronym> in my drive!</para>
</question>

<answer>
<para>Try running <userinput><command>cdparanoia</command>
<option>-vsQ</option></userinput> as yourself (not <systemitem
class="username">root</systemitem>). Do you see a track list? If not,
make sure you have permission to access the <acronym>CD</acronym>
device. If you're using <acronym>SCSI</acronym> emulation (possible if
you have an <acronym>IDE</acronym> <acronym>CD</acronym> writer) then
make sure you check permissions on the generic <acronym>SCSI</acronym>
device, which is probably <filename
class="devicefile">/dev/sg0</filename>, <filename
class="devicefile">/dev/sg1</filename>, etc. If it still doesn't work,
try typing <userinput>audiocd:/?device=/dev/sg0</userinput> (or similar)
to tell kio_audiocd which device your &CD-ROM; is.</para> 
</answer>
</qandaentry>
</qandaset>


</article>
