manual/include/working-with-markers.html

<p>
  It is very useful to be able to tag different locations in a session for
  later use when editing and mixing. Ardour supports both
  <dfn>locations</dfn>, which define specific positions in time,
  and <dfn>ranges</dfn> which define a start and end position in time.
</p>
<p>
  In addition to the standard location markers, there are several more kinds of
  special markers:
</p>
<ul>
  <li>
    <dfn>BBT markers</dfn> make it possible to restart the count of bars and
    beats multiple times in a session.
  </li>
  <li>
    <dfn>Time signature markers</dfn> allow changing the time signature from
    e.g. 4/4 to 6/8 and then to 3/4 within the same composition.
  </li>
  <li>
    <dfn>Tempo markers</dfn> allow changing tempo within the same composition
    either abruptly or gradually.
  </li>
  <li>
    <dfn>Range markers</dfn> helps preserving selections (ranges) by storing
    them in the project and giving them telling names.
  </li>
  <li>
    The <dfn>loop range</dfn> defines the start and end points for Looping.
  </li>
  <li>
    The <dfn>punch range</dfn> defines the in and out points for punch
    recording.
  </li>
  <li>
    <dfn>CD markers</dfn> are locations that are restricted to legal
    <dfn>CD sector boundaries</dfn>. They can be used to add track index
    markers to compact disc images.
  </li>
  <li>
    <dfn>Cue markers</dfn> allow integrating elements of non-linear grid-based
    workflow into the linear timeline-based workflow by launching and stopping
    user-defined cues at particular points in time.
  </li>
</ul>