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 anyway, 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>