149 lines
6.1 KiB
HTML
149 lines
6.1 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 desktop
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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
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worldwide user base. As a result, it is a common platform for people
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who want to use Ardour and other tools for music creation and
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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
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some configuration, in order for the user to gain realtime privilege
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(read below).
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Ubuntu Studio, which is an official flavor of Ubuntu, and thus shares
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the repositories with Ubuntu, has this already configured.
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Other distributions, such as KXStudio, and Dreamstudio are largely based
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on Ubuntu, and like Ubuntu Studio, has these settings preconfigured, while
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also containing customized versions of Ubuntu packages, which often are
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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
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packages, as a result of a different building method. For this reason,
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Ardour developers highly recommend you to install the official
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ready-to-run version of the program that you can get 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 official Ardour forums or other
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support 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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<ol>
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<li>Download the latest release from <a href="https://community.ardour.org/download">
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ardour.org</a>.</li>
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<li><kbd class="mouse">Right+Click</kbd> 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
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run as 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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</p>
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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 the
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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
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desktop. However, it is not capable of the type of performance that
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tools like Ardour require and in particular does not offer the
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possibility of sending audio between applications that can make the
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Linux audio environment a very 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
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will not run correctly (if at all) if it needs to use the same
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soundcard/audio interface that PulseAudio is using. And since on
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Ubuntu, PulseAudio is configured by default to always use the
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(typically single) audio interface on your computer, this is a bit
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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
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agreed upon a mechanism by which PulseAudio and JACK could cooperate
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in their use of a single soundcard. Whether or not PulseAudio is running by
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default, when JACK starts up it sends out a request to use the
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soundcard. If PulseAudio is running, it will give up its use of the
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soundcard to allow JACK to take over (and can optionally be told to
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route its own audio through JACK). When JACK finishes, it sends out
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another message, and PulseAudio can once again use the soundcard
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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
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12.04 and 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
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soundcard when JACK asks
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(<a href="https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1163638">LP:
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#1163638</a>,
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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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<samp>Cannot start JACK</samp> (though see the next section for other
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causes of this)
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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
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(12.04 and 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
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operating system facilities called <dfn>realtime scheduling</dfn> and
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<dfn>memory locking</dfn>. This means that you, the user who starts JACK, must be
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allowed access to these facilities. By default, Ubuntu does create a
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user group that has this permission but—it does not put new
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users into this group by default. Read more about why <a href="https://wiki.ubuntu.com/Audio/TheAudioGroup">here</a>.
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Consequently, you will not have permission to run JACK in the way you 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 as
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it starts up. This output may be hidden in the Messages window of
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QJackctrl (aka JACK Control), so you 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
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named /etc/security/limits.d/audio.conf.disabled, rename it to the former.
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Run the command
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</p>
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<kbd class="cmd lin">sudo usermod -a -G audio
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<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/resources
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of the Ardour team, the <dfn>Ubuntu Studio Project</dfn> has requested that
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issues and bug reports related to Ubuntu, Ubuntu Studio and other
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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><a href="http://ubuntustudio.org">The Ubuntu Studio Homepage</a></p>
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<p><a href="http://ubuntuforums.org/forumdisplay.php?f=335">The Ubuntu Studio Forums.</a></p>
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<p><a href="https://help.ubuntu.com/community/UbuntuStudio/MailLists">Information on the Ubuntu Studio Mailing Lists.</a></p>
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<p><a href="https://help.ubuntu.com/community/UbuntuStudio/IRC">Information on the Ubuntu Studio IRC channel.</a> #ubuntustudio on irc.freenode.net</p>
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