manual/include/snapshots.html

<p>
  A <dfn>snapshot</dfn> is a backup of the current state of a session. It differs
  from a simple save by allowing branching. It is a "frozen" version of the session
  at a certain point in time.
</p>
<p>
  For example, creating a snapshot before changing the entire arrangement of a
  piece, or drastically altering the signal processing provides  a reference to
  come back to, should that not work out.
</p>
<p>
  This is accomplished by using either of the <kbd class="menu">Session &gt;
  Snapshot</kbd> menus. A small dialog will appear, allowing to enter a name for
  the snapshot. The default name is based on the current date and time.
</p>

<p>
  The difference between the two snapshot menus is:
</p>
<table>
  <tr>
    <td><kbd class="menu">Snapshot (& keep working on current version)...</kbd></td>
    <td>Saves a snapshot of the session, but keeps the current session active, i.e. any
      subsequent <kbd class="menu">Session &gt; Save</kbd> will overwrite the original
      session, and the snapshot will remain unchanged.</td>
  </tr>
  <tr>
    <td><kbd class="menu">Snapshot (& switch to new version)...</kbd></td>
    <td>Saves a snapshot of the session, and uses this snapshot as the current
      active session, i.e. any subsequent <kbd class="menu">Session &gt; Save</kbd>
      will overwrite the snapshot, and the original session will remain unchanged.</td>
  </tr>
</table>

<p>
  Any number of snapshots can be created.
</p>
<p class="warning">
  Creating a snapshot does <strong>not</strong> modify the session,
  nor does it save the session. Instead, it saves an alternate version
  of the session, within the session folder. The snapshot shares all data
  present in the session.
</p>

<h2>Switching to a Snapshot</h2>
<p>
  Switching to an existing snapshot is done by navigating the
  <a href="@@the-snapshot-list">Snapshot List</a> and clicking the the name of
  the desired snapshot. Ardour will switch to the snapshot, and, if there are
  unsaved changes in the current session, offer to save them.
</p>

<h2>Starting Ardour With a Snapshot</h2>
<p>
  Since a snapshot is just another session file stored within the session
  folder, that "version" can be chosen when loading an existing session.
  The browser in the "Open Session" dialog will show an expander arrow for
  sessions that have more than one session file (i.e. snapshots)
  present. Clicking on it shows the list, and then clicking on the name of the
  snapshot loads it.
</p>