manual/include/working-with-regions.html

<h2>Working With Regions</h2>

<p>
  <dfn>Regions</dfn> are the basic elements of editing and composing in
  Ardour. In most cases, a region represents a single contiguous section of one or
  more media files. Regions are defined by a fixed set of attributes:
</p>

<ul>
  <li>the audio or <abbr title="Musical Instrument Digital Interface">MIDI</abbr>
    <dfn>source file(s)</dfn> they represent,</li>
  <li>an <dfn>offset</dfn> (the "start point") in the audio or MIDI file(s), and</li>
  <li>a <dfn>length</dfn>.</li>
</ul>

<p>
  When placed into a playlist, they gain additional attributes:
</p>

<ul>
  <li>a <dfn>position</dfn> along the timeline, and</li>
  <li>a <dfn>layer</dfn>.</li>
</ul>

<p>
  There are other attributes as well, but they do not <em>define</em> the
  region. Things to know about regions:
</p>

<h3>Regions Are Cheap</h3>

<p>
  By themselves, regions consume very little in terms of computer's resources.
  Each region requires a small amount of memory, and represents a rather small
  amount of CPU work if placed into an active track. So, multiplying regions creation
  whenever needed should not be much of an issue CPU wise.
</p>

<h3>Regions Are Not Files</h3>

<p>
  Although a region can represent an entire audio file, they are never
  equivalent to an audio file. Most regions represent just parts of an audio
  file(s) on disk, and removing a region from a track has nothing to do with
  removing the audio file(s) from the disk (the <kbd class="menu">Destroy</kbd>
  operation, one of Ardour's few destructive operations, can affect this).
  Changing the length of a region has no effect on the audio file(s) on disk.
  Splitting and copying regions does not alter the audio file in any way, nor does
  it create new audio files (only <dfn>recording</dfn>, and the <kbd
  class="menu">Export</kbd>, <kbd class="menu">Bounce</kbd> and <kbd
  class="menu">Reverse</kbd> operations create new audio files).
</p>