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<title>Questions and answers</title>
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This section answers some frequently asked questions about &arts;.
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<sect1 id="faq-general">
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<title>General Questions</title>
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<qandaset id="faqlist">
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Does &kde; support my sound card for audio output?
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&kde; uses &arts; to play sound, and &arts; uses the &Linux; kernel
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sound drivers, either <acronym>OSS</acronym> or <acronym>ALSA</acronym>
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(using <acronym>OSS</acronym> emulation). If your sound card is
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supported by either <acronym>ALSA</acronym> or <acronym>OSS</acronym>
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and properly configured (&ie; any other &Linux; application can output
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Is there sound support on platforms other than &Linux;?
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There is currently only support for <acronym>OSS</acronym> (or
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compatible) drivers on other platforms (⪚ FreeBSD). You are welcome
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to contribute by adding support for other platforms. The relevant source
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code is <filename>kdelibs/arts/flow/audiosubsys.cc</filename>.
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I can't play <literal role="extension">wav</literal> files with &artsd;!
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Check that &artsd; is linked to <filename>libaudiofile</filename>
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(<userinput><command>ldd</command>
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<parameter>artsd</parameter></userinput>). If it isn't, download
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kdesupport, recompile everything, and it will work.
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I hear sound when logged in as <systemitem
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class="username">root</systemitem> but no other users have sound!
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The permissions of the file <filename
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class="devicefile">/dev/dsp</filename> affect which users will have
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sound. To allow everyone to use it, do this:
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Log in as <systemitem class="username">root</systemitem>.
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Open a &konqueror; window.
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Go into the <filename class="directory">/dev</filename> directory.
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Click on the file <filename>dsp</filename> with the
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<mousebutton>right</mousebutton> mouse button, and choose properties.
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Click on the <guilabel>Permissions</guilabel> tab.
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Check the <guilabel>Read</guilabel> and <guilabel>Write</guilabel> check
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boxes in all sections.
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Click on <guibutton>OK</guibutton>.
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You can achieve the same effect in a terminal window using the command
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<userinput><command>chmod</command> <option>666</option>
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<parameter>/dev/dsp</parameter></userinput>.
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For restricting access to sound to specific users, you can use group
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permissions. On some &Linux; distributions, for instance Debian/Potato,
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<filename class="devicefile">/dev/dsp</filename> is already owned by a
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group called <systemitem class="groupname">audio</systemitem>, so all
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you need to do is add the users to this group.
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This helps for &artsd;, but what about &kmix;, &kmid;, &kscd;,&etc;?
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There are various other devices which provide functionality accessed by
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multimedia applications. You can treat them in the same way, either by
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making them accessible for everyone, or using groups to control
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access. Here is a list, which may still be incomplete (also if there are
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various devices in a form like <filename
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class="devicefile">midi0</filename>, <filename
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class="devicefile">midi1</filename>, ..., then only the 0-version is
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<filename class="devicefile">/dev/admmidi0</filename>
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<filename class="devicefile">/dev/adsp0</filename>
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<filename class="devicefile">/dev/amidi0</filename>
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<filename class="devicefile">/dev/amixer0</filename>
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<filename class="devicefile">/dev/audio</filename>
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<filename class="devicefile">/dev/audio0</filename>
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<filename class="devicefile">/dev/cdrom</filename>
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<filename class="devicefile">/dev/dmfm0</filename>
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<filename class="devicefile">/dev/dmmidi0</filename>
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<filename class="devicefile">/dev/dsp</filename>
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<filename class="devicefile">/dev/dsp0</filename>
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<filename class="devicefile">/dev/midi0</filename>
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<filename class="devicefile">/dev/midi0</filename>
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<filename class="devicefile">/dev/midi00</filename>
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<filename class="devicefile">/dev/midi00</filename>
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<filename class="devicefile">/dev/mixer</filename>
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<filename class="devicefile">/dev/mixer0</filename>
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<filename class="devicefile">/dev/mpu401data</filename>
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<filename class="devicefile">/dev/mpu401stat</filename>
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<filename class="devicefile">/dev/music</filename>
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<filename class="devicefile">/dev/rmidi0</filename>
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<filename class="devicefile">/dev/rtc</filename>
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<filename class="devicefile">/dev/sequencer</filename>
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<filename class="devicefile">/dev/smpte0</filename>
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<filename class="devicefile">/dev/sndstat</filename>
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<para>What can I do if artsd doesn't start or crashes while running?</para>
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First of all: try using the default settings in &kcontrol; (or if you
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are starting manually, don't give additional options besides maybe
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<userinput><option>-F</option><parameter>10</parameter>
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<option>-S</option><parameter>4096</parameter></userinput> for
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latency). Especially <emphasis>full duplex is likely to break</emphasis>
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with various drivers, so try disabling it.
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A good way to figure out why &artsd; doesn't start (or crashes while
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running) is to start it manually. Open a &konsole; window, and do:
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<screen width="40"><prompt>%</prompt> <userinput><command>artsd</command> <option>-F</option><parameter>10</parameter> <option>-S</option><parameter>4096</parameter>></userinput></screen>
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You can also add the <option>-l0</option> option, which will print more
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information about what is happening, like this:
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<screen width="40"><prompt>%</prompt> <userinput><command>artsd</command> <option>-l0</option> <option>-F</option><parameter>10</parameter> <option>-S</option><parameter>4096</parameter></userinput></screen>
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Doing so, you will probably get some useful information why it didn't
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start. Or, if it crashes when doing this-and-that, you can do
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this-and-that, and see <quote>how</quote> it crashes. If you want to
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report a bug, producing a backtrace with <command>gdb</command> and/or
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an <command>strace</command> may help finding the problem.
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<para>Can I relocate &artsd; (move compiled files to another
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You can't relocate &arts; perfectly. The problem is that &artswrapper;
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has the location of &artsd; compiled in due to security reasons. You can
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however use the <filename>.mcoprc</filename> file
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(TraderPath/ExtensionPath entries) to at least make a relocated &artsd;
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find it's components. See the <link linkend="the-mcoprc-file">chapter
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about the <filename>.mcoprc</filename> file</link> for details on how to
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<para>Can I compile &arts; with gcc-3.0?</para>
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Short answer: no, &arts; will not work if you compile it with gcc-3.0.
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Long answer: In the official release, there are two gcc-3.0 bugs which affect
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&arts;. The first, gcc-3.0 bug c++/2733 is relatively harmless (and has to do
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with problems with the asm statement). It breaks compilation of convert.cc. It
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has been fixed in the gcc-3.0 CVS, and will no longer be a problem with
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gcc-3.0.1 and higher. A workaround has also been added to the CVS version
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The second gcc-3.0 bug, c++/3145 (which is generation of wrong code for some
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cases of multiple virtual inheritance) is critical. Applications like &artsd;
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will simply crash on startup when compiled with gcc-3.0. Even if some progress
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has been made in the gcc-3.0 branch at time of this writing, still &artsd;
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crashes quite often, unpredictably.
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<para>What applications run under &arts;?</para>
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Obviously, all of the applications included with &kde; are
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&arts;-aware. This includes:
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<listitem><para>&noatun;</para></listitem>
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<listitem><para>&artsbuilder;</para></listitem>
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<listitem><para>&aktion;</para></listitem>
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<listitem><para>&kmid;</para></listitem>
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<listitem><para>&kmidi;</para></listitem>
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<listitem><para>&kmix;</para></listitem>
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<listitem><para>&kscd;</para></listitem>
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<listitem><para>&kde; games such as &kpoker; and
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&ktuberling;</para></listitem>
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Some &kde; applications that are not yet included in the &kde; release
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(⪚ in kdenonbeta) also support &arts;, including:
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<listitem><para>&brahms;</para></listitem>
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<listitem><para><application>Kaboodle</application></para></listitem>
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<listitem><para><application>Kdao</application></para></listitem>
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The following non-&kde; applications are known to work with &arts;:
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<listitem><para><application>xmms</application> (with &arts;
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plug-in)</para></listitem>
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<listitem><para>Real Networks <application>RealPlayer</application> 8.0
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(works with &artsdsp;; native &arts; support is being
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considered)</para></listitem>
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The following applications are known <emphasis>not</emphasis> to work
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<listitem><para>none</para></listitem>
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See also the answers to the questions in the section on
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<link linkend="faq-non-arts">non-&arts; applications</link>.
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This section is incomplete -- if you have more information on supported
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and unsupported applications, please send them to the author so they can
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<sect1 id="faq-non-arts">
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<title>Non-&arts; Applications</title>
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As soon as &kde; is running, no other application can access my sound device!
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Since the &arts; sound server used by &kde; is running, it is using the
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sound device. If the server is idle for 60 seconds, it will
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auto-suspend and release it automatically.
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You said it suspends after 60 seconds, it doesn't for me!
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If you start artsd from the KDE control panel, the default is to suspend
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after 60 seconds. If you start artsd from the command line you need to
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use the -s option to specify the autosuspend time, otherwise it will
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default to disabling the autosuspend feature.
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Currently it doesn't suspend when using full duplex. Turn full duplex
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off from the &kcontrol; and it will suspend. Disabling full duplex is
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generally a good idea anyway if you only use &arts; for playing audio
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How can I run old, non-&arts; applications?
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Run them using the &artsdsp;. For instance, if you normally would run:
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<screen><prompt>%</prompt> <userinput><command>mpg123</command> <option>foo.mp3</option></userinput></screen>
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<para>instead use:</para>
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<screen><prompt>%</prompt> <userinput><command>artsdsp</command> <option>mpg123 foo.mp3</option></userinput></screen>
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This will redirect the sound output to &arts;. This method doesn't
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require changes to the applications. It is something of an ugly hack
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however, and does not yet fully support all features of the sound card
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device, so some applications may not work.
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I can't run &artsdsp; with any application, it always crashes!
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You need a recent version of the glibc library; &artsdsp; will not work
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reliably on some older &Linux; distributions. For instance, on Debian
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2.1 (which is glibc 2.0 based) it doesn't work, while on Debian 2.2
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(which is glibc 2.1.3 based), it does.
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Are there theoretical limitations with some applications that will
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prevent them from ever working with &artsdsp;?
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No. Using &artsdsp; can result in slightly more latency and
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<acronym>CPU</acronym> usage that using the &arts;
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<acronym>API</acronym>s directly. Other than that, any application that
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doesn't work should be considered a bug in &artsdsp;. The technique used
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by &artsdsp; should, if implemented properly, allow
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<emphasis>every</emphasis> application to work with it (including large
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applications like <application>Quake</application> 3).
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What can I do if an application doesn't work with &artsdsp;?
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You can wait for &artsd; to suspend or use the command
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<userinput><command>artsshell</command>
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<option>suspend</option></userinput> to ask the server to suspend
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itself. You will only be able to suspend the server if no &arts;
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applications are currently using it, and no &arts; applications will be
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able to run when the server is suspended.
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If the server is busy, a crude but effective way to get rid of it is:
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<screen><prompt>%</prompt> <userinput><command>killall</command> <option>artsd</option> ; <command>killall</command> <option>artswrapper</option></userinput>
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<lineannotation>Now start your own application.</lineannotation>
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<prompt>%</prompt> <userinput><command>kcminit</command> <option>arts</option></userinput>
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Any currently running &arts; applications may crash, however, once you
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What about applications written for &kde; 1.x?
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If you are running &kde; 1.x applications, which output sound via the
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&kde; 1 audio server, you will need to run
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<application>kaudioserver</application> to make it work. You can start
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<application>kaudioserver</application> in the same way than other
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non-&arts;-applications:
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<prompt>%</prompt> <userinput><command>artsdsp</command> <option>kaudioserver</option></userinput>
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You will need to have installed kaudioserver (from the same source where
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you got your &kde; 1.x applications from) - it belongs to &kde; 1.x, not
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What about applications using the enlightened sound daemon,
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<acronym>ESD</acronym>?
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The issue is similar than with
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<application>kaudioserver</application>. Such applications will need a
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running esd server. You can start <command>esd</command> via &artsdsp;,
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and every <acronym>ESD</acronym> aware application should work fine,
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<prompt>%</prompt> <userinput><command>artsdsp</command> <option>esd</option></userinput>
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<sect1 id="faq-latency">
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<title>Latency</title>
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I sometimes hear short pauses when listening to music, is this a bug?
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This is most likely not a bug, but caused by the fact that the &Linux;
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kernel is not very good at real-time scheduling. There are situations
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where &arts; will not be able to keep up with playback. You can,
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however, enable real-time rights (via &kcontrol;), and use a large
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latency setting (like <guilabel>250ms</guilabel> or <guilabel>don't
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care</guilabel>), which should improve the situation.
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What's the effect of the response time setting?
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The help text for this setting in the &kcontrol; can be misleading. A
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lower value means that &arts; will take less time to respond to external
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events (&ie;. the time that it takes between closing a window and
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hearing a sound played by &artsd;). It will also use more
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<acronym>CPU</acronym> resources, and be more likely to cause
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Is there anything else I can do to prevent pauses?
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For users of <acronym>IDE</acronym> drives, you can use the
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<command>hdparm</command> command to put your <acronym>IDE</acronym>
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drive in <acronym>DMA</acronym> mode. A word of warning: this does not
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work on all hardware, and can result in having to do a hard reset or in
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rare cases, data loss. Read the documentation for the
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<command>hdparm</command> command for more details. I have successfully
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used the following command:
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<prompt>%</prompt> <userinput><command>hdparm</command> <option>-c1</option> <option>-d1</option> <option>-k1</option> <option>-K1</option> <parameter>/dev/hda</parameter></userinput>
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You need to run this after every boot, so you might want to place it in
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a system startup script (how to do this distribution specific, on Debian
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&Linux; it is usually put in <filename>/etc/rc.boot</filename>).
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Why is &artsd; taking so much <acronym>CPU</acronym> time?
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Check your response time settings. However, the current version is not
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yet really optimized. This will improve, and until then no real
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prediction can be made how fast &artsd; can or can't be.
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<sect1 id="faq-network">
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<title>Network Transparency</title>
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What do I need for network transparency?
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Enable it in the &kcontrol; <guilabel>Sound Server</guilabel> settings
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(<guilabel>enable X11 server for security information</guilabel> and
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<guilabel>network transparency</guilabel>). Then copy your
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<filename>.mcoprc</filename> to all machines you plan to use network
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transparency from. Log in again. Make sure that the hosts that interact
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know each other by name (&ie; they have resolvable names or are in
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<filename>/etc/hosts</filename>).
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This should be all you need to do. However, if it still doesn't work
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here are some additional details. The &arts; sound server process,
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&artsd;, should only run on one host, the one with the sound card where
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the sound should be played. It can be started automatically on login by
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&kde; (if you configure that in &kcontrol;), or manually using something
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<prompt>%</prompt> <userinput><command>artsd</command> <option>-n</option> <option>-F</option> <parameter>5</parameter> <option>-S</option> <parameter>8192</parameter></userinput>
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The <option>-n</option> parameter is for network transparency, while the
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others configure latency.
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Your <filename>.mcoprc</filename> file should have this entry:
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<userinput>GlobalComm=Arts::X11GlobalComm</userinput>
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on all machines involved, in order for network transparency to work,
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This is what is enabled by the <guilabel>X11 server for security
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information</guilabel> control panel setting.
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Finally, in any &kde; version in the 2.0.x series, there is a bug which
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applies if you don't have a domain name set. Clients of &artsd; try to
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find where to connect to via the <systemitem
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class="systemname"><replaceable>hostname</replaceable>.<replaceable>domainname</replaceable></systemitem>
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combination. If your domain name is empty, it will try to connect to
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class="systemname"><replaceable>hostname</replaceable></systemitem>. (note
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the extra dot). Adding an entry like this to
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<filename>/etc/hosts</filename> (&ie; <userinput>orion.</userinput> if
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your hostname is <systemitem class="systemname">orion</systemitem>)
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works around the problem.
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How do I debug network transparency if it doesn't work?
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Assuming you have the &kde; source code, go to <filename
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class="directory">kdelibs/arts/examples</filename>, and run
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<userinput><command>make</command> <option>check</option></userinput> to
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compile some programs, including
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<application>referenceinfo</application>. Then run
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<prompt>%</prompt> <userinput><command>./referenceinfo</command> <option>global:Arts_SimpleSoundServer</option></userinput>
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The output will indicate the host name and port being used by
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&arts;. For example, <computeroutput>tcp:orion:1698</computeroutput>
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would mean that any client trying to use network transparency should
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know how to reach host <systemitem
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class="systemname">orion</systemitem>.
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<sect1 id="faq-other">
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<title>Other Issues</title>
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I can't use &artsbuilder;. It crashes when executing a module!
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The most likely cause is that you are using old structures or modules
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which aren't supported with the &kde; 2 version. Unfortunately the
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documentation which is on the web refers to &arts;-0.3.4.1 which is
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quite outdated. The most often reported crash is: that performing an
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execute structure in &artsbuilder; results in the error message
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<errorname>[artsd] Synth_PLAY: audio subsystem is already
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You should use a Synth_AMAN_PLAY instead of a Synth_PLAY module and the
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problem will go away. Also see the &artsbuilder; help file (hit
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<keycap>F1</keycap> in &artsbuilder;).
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Recent versions of &artsbuilder; (&kde; 2.1 beta 1 and later) come with
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a set of examples which you can use.
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