manual/include/transport-masters.html

<p>
	The <dfn>Transport Masters</dfn> dialog allows selecting a transport master
	(a timecode source) for Ardour to sync to, as well as tweaking additional
	settings.
</p>

<figure>
  <img style="width:75%;" src="/images/transport-masters.png" alt="Transport Masters">
  <figcaption>
    Transport Masters
  </figcaption>
</figure>

<p>
	Supported protocols are:
</p>

<ul>
	<li>JACK Transport</li>
	<li>MIDI Time Code (MTC)</li>
	<li>Linear (or Longitudinal) Timecode (LTC)</li>
	<li>MIDI Beat Clock, or MIDI Clock</li>
</ul>

<p>
	For each type of supported protocol it's possible to select the port
	to read timecode signal from, view sync position and drift (delta), see
	when any message was received the last time, and toggle additional
	options.`
</p>

<h2>Selecting a Transport Master</h2>

<p>
	The dialog collects all transport masters information and settings in one
	place, however Ardour can sync only to one timecode source at a time.
	Clicking the radio button to the left of the master's name selects that
	transport master.
</p>

<p>
	It is necessary to also select an audio or MIDI port (depending on the
	protocol) to read timecode data from. Relevant ports are listed for each
	transport master in the dropdown list in the <dfn>Source</dfn> section.
</p>

<h2>Keeping Track of The Sync</h2>

<p>
	<dfn>Format</dfn> displays the timecode format for each transport master
	depending on the specifics of that master's protocol. E.g. while MTC and
	LTC will display a frame rate such as 25 fps, MIDI Clock will be
	transmitting tempo such as 120 beats per minute.
</p>

<p>
	<dfn>Sync Position + Delta</dfn> displays current location as per timecode
	as well as the difference between current location in Ardour and the
	location per timecode source. This difference (delta) accumulates as long
	as Ardour's transport isn't rolling.
</p>

<p>
	<dfn>Last Message + Age</dfn> displays the latest location transmitted
	by the timecode source, as well as the time since the last transmission
	was received.
</p>

<h2>Setting Additional Options</h2>

<p>
	It's possible to set several additional options.
</p>

<p>
	<dfn>Active Commands</dfn> makes it possible to perform certain types
	of actions in Ardour at the cost of decoupling from the transport master.
	Supported options are:
</p>

<ul>
	<li>Accept start/stop commands (displays 'Start/Stop' on the button)</li>
	<li>Accept speed-changing commands (displays 'Speed' on the button)</li>
	<li>Accept locate commands (displays 'Locate' on the button)</li>
</ul>

<p>
	When only one command is enabled, its short name will displayed at the
	button's caption (see above). When two out of three are enabled,
	the button's caption will be 'Complex'. When all three options are enabled,
	the caption will be 'All'.
</p>

<p>
	The easiest way to select two or three options at a time is to open the
	drop-down menu, use arrow up/down keys to navigate to the option of interest,
	the press <kbd class="button">Spacebar</kbd> to toggle that option without
	subsequently closing the drop-down menu.
</p>

<p>
	<dfn>Clock Synced</dfn> — when this option is enabled, the external
	timecode source is assumed to be sample-clock synced to the audio interface
	that is being used by Ardour
</p>

<p>
	<dfn>29.97/30</dfn> — when this option is enabled, the external timecode
	source is assumed to use 29.97 fps exactly rather than 30000/1001 (which is
	29.97002997).
</p>

<p>
	Both <dfn>Clock Synced</dfn> and <dfn>29.97/30</dfn> options are not
	applicable to <dfn>MIDI Beat Clock</dfn> that operates in the musical time
	domain and transmits beats per minute rather that seconds and frames.
</p>

<h2>Adding and Removing Custom Transport Masters</h2>

<p>
	It is possible to <dfn>add</dfn> additional masters of the same type, e.g.
	two difference sources of LTC.
</p>

<p>
	Clicking <kbd class="button">Add a New Transport Master</kbd> opens a new
	dialog.
</p>

<figure>
  <img style="width:50%;" src="/images/add-transport-master.png" alt="Add a new transport master">
  <figcaption>
    Add a new transport master
  </figcaption>
</figure>

<p>
	It's usually a good idea to give the custom transport master a descriptive
	name, especially if there are multiple ones available using the same
	protocol.
</p>

<p>
	The next step is selecting the audio or MIDI port where the timecode signal
	will be coming from.
</p>

<p>
	Additional transport masters can be <dfn>removed</dfn> with a single click.
	Every custom transport master has a button with a crosshair icon
	<kbd class="button">X</kbd> to the right of the window. No confirmation
	will be asked upon clicking this button.
</p>