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><dfn><abbr title="Microsoft Multimedia Environment">MME</abbr></dfn> is the
  standard MIDI framework on Windows systems.</td></tr>
</table>

<p class="note">
  <dfn><abbr title="JACK Audio Connection Kit">JACK</abbr></dfn> is an
  alternate audio system which Ardour can utilize for both audio and
  MIDI.  JACK is used to route audio between independent applications,
  and is now considered an advanced use case which is not recommended
  for most users.  Users with a need to use JACK for audio routing
  should consult the latest documentation at
  the <a href="https://jackaudio.org/">JACK website</a>.
</p>