179 lines
6.2 KiB
HTML
179 lines
6.2 KiB
HTML
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<p>
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<dfn>Ubuntu Linux</dfn> is the most popular variety of Linux in use on
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desktop and laptop systems. It has the backing of a for-profit corporation
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(Canonical Inc.), a defined philosophy and a huge and worldwide user base. As
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a result, it is a common platform for people who want to use Ardour and other
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tools for music creation and pro-audio work.
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</p>
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<h2>High Level Recommendations for Ubuntu Users</h2>
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<p>
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Currently, installing pro audio applications on vanilla Ubuntu requires some
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configuration, in order for the user to gain realtime privilege (read below).
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Ubuntu Studio, which is an official flavor of Ubuntu, and thus shares the
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repositories with Ubuntu, has this already configured. Other distributions,
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such as KXStudio, and Dreamstudio are largely based on Ubuntu, and like
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Ubuntu Studio, has these settings preconfigured, while also containing
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customized versions of Ubuntu packages, which often are more up to date.
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</p>
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<h2>Installing Ardour</h2>
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<p>
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There may be unintended differences, and even bugs in Ubuntu native packages,
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as a result of a different building method. For this reason, Ardour
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developers highly recommend installing the official ready-to-run version of
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the program that can be downloaded from <a
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href="https://community.ardour.org/download">ardour.org</a>, as Ubuntu native
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packages are not supported in the official Ardour forums or other support
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channels.
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</p>
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<p>
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Follow these steps to install the latest version of Ardour:
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</p>
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<ol>
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<li>Download the latest release from <a
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href="https://community.ardour.org/download">ardour.org</a>.</li>
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<li><kbd class="mouse">Right</kbd>-click the downloaded file and choose
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properties.</li>
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<li>Click the Permissions tab and check the option "Allow this file to run as
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a program".</li>
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<li>Close the dialog and double-click the file.</li>
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<li>Follow the prompts.</li>
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</ol>
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<h2>Problems with the interaction between PulseAudio and JACK</h2>
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<h3>Background Info</h3>
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<p>
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Like many distributions, Ubuntu has decided to use <dfn>PulseAudio</dfn> as
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the default audio system. PulseAudio is a rich and capable system that
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provides excellent services for typical users of Linux on the desktop.
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However, it is not capable of the type of performance that tools like Ardour
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require and in particular does not offer the possibility of sending audio
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between applications that can make the Linux audio environment a very
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interesting one.
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</p>
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<p>
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This would not be a problem if it were not for the fact that JACK will not
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run correctly (if at all) if it needs to use the same soundcard/audio
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interface that PulseAudio is using. And since, PulseAudio on Ubuntu is
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configured by default to always use the (typically single) audio interface on
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the computer, this is a bit of a problem.
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</p>
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<p>
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The developers of JACK and PulseAudio got together in 2009 and agreed upon a
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mechanism by which PulseAudio and JACK could cooperate in their use of a
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single soundcard. Whether or not PulseAudio is running by default, when JACK
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starts up it sends out a request to use the soundcard. If PulseAudio is
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running, it will give up its use of the soundcard to allow JACK to take over
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(and can optionally be told to route its own audio through JACK). When JACK
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finishes, it sends out another message, and PulseAudio can once again use the
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soundcard directly.
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</p>
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<h3>What is the problem?</h3>
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<p>
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The specific issues known at this time for all flavors of Ubuntu 12.04 and
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12.10 are:
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</p>
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<ul>
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<li>a bug in PulseAudio that causes it not to give up the soundcard when JACK
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asks (<a
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href="https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1163638">LP:
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#1163638</a>, fixed in Ubuntu 13.04).</li>
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</ul>
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<h3>Symptoms</h3>
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<p>
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A message like <samp>Cannot start JACK</samp> in the output from JACK as it
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starts up (though see the next section for other causes of this). This output
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may be hidden in the Messages window of QJackCtl (aka JACK Control), so one
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should check there.
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</p>
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<h3>How to fix</h3>
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<p>
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These bugs do not affect releases from 13.04, and earlier releases (12.04 and
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12.10) are in the process of being fixed.
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</p>
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<h2>Problems with JACK configuration</h2>
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<h3>What is the problem?</h3>
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<p>
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To function as intended, JACK needs to run with access to two operating
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system facilities called <dfn>realtime scheduling</dfn> and <dfn>memory locking</dfn>. This means that the user who starts JACK <em>must</em> be
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allowed access to these facilities. By default, Ubuntu does create a user
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group that has this permission but—it does not put new users into this
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group by default. Read more about why <a
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href="https://wiki.ubuntu.com/Audio/TheAudioGroup">here</a>. Consequently,
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the user will not have permission to run JACK in the way they should.
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</p>
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<h3>Symptoms</h3>
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<p>
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A message like <samp>Cannot lock down memory</samp> in the output from JACK
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as it starts up. This output may be hidden in the Messages window of QJackCtl
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(aka JACK Control), so one should check there.
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</p>
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<h3>How to fix</h3>
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<p>
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Make sure the file /etc/security/limits.d/audio.conf exists. If it is named
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/etc/security/limits.d/audio.conf.disabled, rename it to the former. Run the
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command:
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</p>
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<kbd class="cmd lin">sudo usermod -a -G audio <em>YOUR-LOGIN-NAME</em></kbd>
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<p>
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Then log out and log in again. On Ubuntu Studio the user is a member of audio
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group by default, but not on other official flavors.
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</p>
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<h2>Reporting Issues</h2>
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<p>
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Given the difficulties in supporting Ubuntu and the limited time and
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resources of the Ardour team, the <dfn>Ubuntu Studio Project</dfn> has
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requested that issues and bug reports related to Ubuntu, Ubuntu Studio and
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other derivitives be directed to them.
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</p>
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<h3>Contact Information for Ubuntu Studio</h3>
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<p>
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<a href="http://ubuntustudio.org">The Ubuntu Studio Homepage</a>
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</p>
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<p>
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<a href="http://ubuntuforums.org/forumdisplay.php?f=335">The Ubuntu Studio
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Forums.</a>
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</p>
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<p>
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<a href="https://help.ubuntu.com/community/UbuntuStudio/MailLists">Information
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on the Ubuntu Studio Mailing Lists.</a>
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</p>
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<p>
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<a href="https://help.ubuntu.com/community/UbuntuStudio/IRC">Information on
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the Ubuntu Studio IRC channel.</a> #ubuntustudio on irc.freenode.net
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</p>
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