title: On Clock and Time
---
-<h2>On Clock and Time</h2>
-
<p>
Synchronisation in multimedia involves two concepts which are often confused: <strong>clock</strong> (or speed) and <strong>time</strong> (location in time).
</p>
</p>
-<h2>Latency compensation and clock sync</h2>
+<h2>Latency Compensation And Clock Sync</h2>
<p>
To achieve sample accurate timecode synchronization, the latency introduced by the audio-setup needs to be known and compensated for.
</p>
-<h2>Calibrating JACK latency</h2>
+<h2>Calibrating JACK Latency</h2>
<p>
Linux DSP guru Fons Adriaensen wrote a tool called <code>jack_delay</code> to accurately measure the roundtrip latency of a closed loop audio chain, with sub-sample accuracy. JACK itself includes a variant of this called <code>jack_iodelay</code>.
-<h3>MTC generator</h3>
+<h3>MTC Generator</h3>
<p>
There are no options. Ardour sends full MTC frames whenever the transport is relocated or changes state (start/stop). MTC quarter frames are sent when the transport is rolling and the transport speed is within 93% and 107%.
-<h3>LTC generator</h3>
+<h3>LTC Generator</h3>
<p>
The volume of the LTC signal can be conigured in in the <code>Preferences > Transport</code> dialog. By default it is set to -18dBFS which corresponds to 0dBu in an EBU calibrated system.
-<h3>JACK transport</h3>
+<h3>JACK Transport</h3>
<p>
When slaved to jack, Ardour's transport will be identical to JACK-transport. As opposed to other slaves, Ardour can be used to control the JACK transport states (stopped/rolling). No port-connections need to be made for jack-transport to work.