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< User:Crantila | FSC
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=== Safely Enable Real-Time Scheduling === | === Safely Enable Real-Time Scheduling === | ||
<ol> | |||
<li>Add yourself, and anybody who uses JACK, to the 'audio' group (instructions for this are probably in an existing Fedora Doc)</li> | |||
<li>Planet CCRMA's version of JACK automatically enables real-time priorities. To make it safer, edit '/etc/security/limits.conf' so that the final lines read: | |||
<pre>@audio - rtprio 99 | <pre>@audio - rtprio 99 | ||
@audio - memlock 4194304 | @audio - memlock 4194304 | ||
@audio - nice -10</pre> | @audio - nice -10</pre></li> | ||
<li>If you are not using PlanetCCRMA's JACK version, then write those lines in!</li> | |||
</ol> | |||
=== Starting and Stopping === | === Starting and Stopping === | ||
Revision as of 05:01, 14 June 2010
What JACK Is, and Why It Exists
(no algorithms)
Knowing When to Use JACK
(no algorithms)
How to Setup Your System for JACK
- must refer to kernel/system optimization section
- by default, in Fedora, when JACK is started, it receives control of the audio devices from PulseAudio. No PA device works until JACK quits
Installation
- run 'yum install jack-audio-connection-kit qjackctl' (this installs JACK and a GUI application to control it, QjackCtl)
- Approve the installation.
Safely Enable Real-Time Scheduling
- Add yourself, and anybody who uses JACK, to the 'audio' group (instructions for this are probably in an existing Fedora Doc)
- Planet CCRMA's version of JACK automatically enables real-time priorities. To make it safer, edit '/etc/security/limits.conf' so that the final lines read:
@audio - rtprio 99 @audio - memlock 4194304 @audio - nice -10
- If you are not using PlanetCCRMA's JACK version, then write those lines in!
Starting and Stopping
- Run QjackCtl from the KMenu or Applications menu
- to start JACK, press "Start"; to stop it press "Stop"
- Use the "Messages" button to see messages, usually errors or warnings
- Use the "Status" button to see various statistics
Adjusting Settings
- Press the "Setup" button
- Run 'cat /proc/asound/cards' to see a list of sound cards in your system, and choose the one you want by name
- Put (for example) 'hw:SB' in the "Interface" field (this is more robust, etc.)
- Adjust the sample rate no higher than the highest supported by your interface; 44100 is CD quality; 48000 is probably sufficient for most uses
- Go to the 'Options' tab, and deselect "Execute script on Startup: artsshell -q terminate", since it's not needed in KDE4 or GNOME