manual/include/configuring-midi.html

<p>
  <dfn><abbr title="Musical Instrument Digital Interface">MIDI</abbr></dfn> is
  a way to describe musical performances and to control music hardware and
  software.
</p>

<p>
  Ardour can import and record MIDI data, and perform a variety of editing
  operations on it. Furthermore, MIDI can be used to control various functions
  of Ardour.
</p>

<h2>MIDI Handling Frameworks</h2>

<p>
  MIDI input and output for Ardour are handled internally by the same "engine" that
  handles audio input and output. However, Ardour can use as many MIDI devices
  as the system can see as there are no syncing difficulties as there would be with audio.
</p>

<table class="dl">
  <tr><th>OS X</th>
  <td><dfn>CoreMIDI</dfn> is the standard MIDI framework on OSX systems.</td></tr>
  <tr><th>Linux</th>
  <td><dfn><abbr title="Advanced Linux Sound API">ALSA</abbr> MIDI</dfn> is the
  standard MIDI framework on Linux systems.</td></tr>
  <tr><th>Windows</th>
  <td>There is no single standard MIDI framework on Windows, but Ardour
  can work with ASIO and others.</td></tr>
</table>

<p class="note">
  On Linux systems, <dfn>QJackCtl</dfn> control software displays ALSA MIDI
  ports under its "ALSA" tab (it does not currently display CoreMIDI ports).
  By contrast, JACK MIDI ports show up under the <kbd class="menu">MIDI</kbd>
  tab in QJackCtl. However, when Ardour is using jackd for audio in and out
  the alsa MIDI ports are not accessable. When Ardour is using ALSA for audio
  in and out then only alsa MIDI ports are accessable.
</p>

<h2>JACK MIDI Configuration</h2>

<p>
  By default, JACK will <strong>not</strong> automatically detect and use
  existing MIDI ports. One of several ways of <dfn>bridging</dfn> between
  the native MIDI frameworks (e.g. CoreMIDI or ALSA) and JACK MIDI must be
  chosen, as described in the following sections.
</p>