3 In order to fully grasp the terms used in Ardour (and this manual), it is
4 necessary to understand what things like sessions, tracks, busses, regions
5 and so on—as used in Ardour—are.
11 An Ardour <dfn>session</dfn> is a container for an entire project. A session
12 may contain an arbitrary number of <dfn>tracks</dfn> and <dfn>busses</dfn>
13 consisting of audio and <abbr title="Musical Instrument Digital
14 Interface">MIDI</abbr> data, along with information on processing those
15 tracks, a mix of levels, and everything else related to the project. A
16 session might typically contain a song, an entire album, or a complete live
21 Ardour sessions are kept in directories; these directories contain one or
22 more <dfn>session files</dfn>, some or all of the audio and MIDI data, and a
23 number of other state files that Ardour requires. The session file describes
24 the structure of the session, and holds automation data and other details.
28 Ardour's session file is written in <abbr title="eXtensible Markup
29 Language">XML</abbr> format, which is advantageous as it is <em>somewhat</em>
30 human-readable and human-editable in a crisis. Sound files are stored in one
31 of a number of optional formats, and MIDI files as <abbr title="Standard MIDI
36 It is also possible for Ardour sessions to reference sound and MIDI files
37 outside the session directory, to conserve disk space and avoid unnecessary
38 copying if the data is available elsewhere on the disk.
42 Ardour has a single current session at all times; if Ardour is started
43 without specifying one, it will offer to load or create one.
47 More details can be found in the <a href="@@sessions">Sessions</a> chapter.
53 A <dfn>track</dfn> is a concept common to most <abbr title="Digital Audio
54 Workstation">DAWs</abbr>, and also used in Ardour. Tracks can record audio or
55 MIDI data to disk, and then replay it with processing. They also allow the
56 audio or MIDI data to be edited in a variety of different ways.
60 In a typical pop production, one track might be used for the kick drum, another for the snare, more perhaps for the drum overheads and others for bass, guitars and vocals.
64 Ardour can record to any number of tracks at one time, and then play those
65 tracks back. On playback, a track's recordings may be processed by any number
66 of plugins, panned, and/or its level altered to achieve a suitable mix.
70 A track's type is really only related to the type of data that it stores on
71 disk. It is possible, for example, to have a MIDI track with a synthesizer
72 plugin which converts MIDI to audio. Even though the track remains MIDI (in
73 the sense that its on-disk recordings are MIDI), its output may be
78 More details can be found in the <a href="@@tracks">Tracks</a> chapter.
81 <h2 id="busses">Busses</h2>
84 <dfn>Busses</dfn> are another common concept in both DAWs and hardware
85 mixers. They are similar in many ways to tracks; they process audio or MIDI,
86 and can run processing plugins. The only difference is that their input is
87 obtained from other tracks or busses, rather than from disk.
91 A bus might typically be used to collect together the outputs of related
92 tracks. Consider, for example, a three track recording of a drum kit; given
93 kick, snare and overhead tracks, it may be helpful to connect the output of
94 each to a bus called "drums", so that the drum kit's level can be set as a
95 unit, and processing (such as equalization or compression) can be applied to
96 the mix of all the tracks. Such busses are also called <dfn>groups</dfn>.
102 A track may contain many segments of audio or MIDI. Ardour contains these
103 segments in things called <dfn>regions</dfn>, which are self-contained
104 snippets of audio or MIDI data. Any recording pass, for example, generates a
105 region on each track that is enabled for recording. Regions can be subjected
106 to many editing operations; they may be moved around, split, trimmed, copied,
111 More details can be found at <a href="@@working-with-regions">Working With
118 The details of what exactly each track should play back is described by a
119 <dfn>playlist</dfn>. A playlist is simply a list of regions; each track
120 always has an active playlist, and can have other playlists which can be
121 switched in and out as required.
125 More details can be found in the <a href="@@playlists">Playlists</a> chapter.
131 Ardour allows processing audio and MIDI using any number of
132 <dfn>plugins</dfn>. These are external pieces of code, commonly seen as VST
133 plugins on Windows or AU plugins on Mac OS X. Ardour supports the following
138 <tr><th><abbr title="Linux Audio Developers' Simple Plugin API">LADSPA</abbr></th>
139 <td>the first major plugin standard for Linux. Many LADSPA plugins are
140 available, mostly free and open-source.</td></tr>
141 <tr><th><abbr title="LADSPA Version 2">LV2</abbr></th>
142 <td>the successor to LADSPA. Lots of plugins have been ported from LADSPA to
143 LV2, and also many new plugins written.</td></tr>
144 <tr><th><abbr title="Virtual Studio Technology">VST</abbr></th>
145 <td>Ardour supports VST plugins that have been compiled for Linux.</td></tr>
146 <tr><th><abbr title="Audio Units">AU</abbr></th>
147 <td>Mac OS X versions of Ardour support AudioUnit plugins.</td></tr>
151 Ardour has some support for running Windows VST plugins on Linux, but this is
152 rather complicated, extremely difficult for the Ardour developers to debug,
153 and generally unreliable, as it requires running a large amount of Windows
154 code in an emulated environment. If it is at all possible, it is strongly
155 advisable to use native LADSPA, LV2 or Linux VST plugins on Linux, or AU on
160 More details can be found at <a href="@@working-with-plugins">Working With