Sessions and Snapshots

Sessions

The Session is the fundamental document type that is created and modified by the Ardour workstation.  A "Session" is a folder on your computer filesystem that contains all the items that pertain to a particular project or "recording/editing/mixing session".

The Session folder includes these files and folders:

• The main session snapshot (session_name.ardour)
• Any additional snapshots (filenames ending in ardour)
• the auto-backup snapshot (session_name.ardour.bak)
• the undo history for the session (session_name.history)
• the instant file (instant.xml) which records the last-used zoom scale and other metadata
• a folder called "interchange" which holds your raw audio files (whether imported or recorded)
• a folder called "export" which contains any files created by the "Export" function
• a folder called "peaks" which contains a waveform rendering of each raw audio file in the session
• a folder called "analysis" which contains transient and pitch information of each raw audio file
• a folder called "dead sounds" which contains sounds which Ardour has detected are no longer used in the session

A session combines some setup information (such as audio and MIDI routing, musical tempo & meter, timecode synchronization, etc.) with one or more Tracks and Buses, and all the Regions and Plug-Ins they contain.

In a traditional recording studio, the Session might be the equivalent to the setup of equipment (including patch bay routing, external gear, track naming strips, etc.) on a given day.

A session typically corresponds with a project such as a song, a collection of songs such as a CD, a reel, etc.

Snapshots

A Snapshot is a file which stores the state of the Session. When you hit Save, all changes are saved to the most recently-opened snapshot.  Snapshots have the file extension ".ardour".

Every Ardour session folder starts with a snapshot file that has the name of the Session.  The use of additional snapshots is entirely optional.

If you would like to create a backup or alternate version of you session, you can create a "Snapshot" of the current state of the session.  This new file is stored inside the session folder and can be opened and edited by Ardour.  It still references the same audio as the primary session file.  By default these snapshots are created with the current date and time.  This supports their most common use, which is as a backup mechanism.

You may use "Open" to open any snapshot file inside the ardour session folder.  This snapshot will now be the subject of any "Save" commands.

Ardour does not currently have a "Save As" function which saves a snapshot and then opens the snapshot file for future "Save" commands.

A common usage for Snapshots beyond just providing a "Save As" functionality, is to utilize snapshots to create sessions for each song that is part of a CD that might be assembled in its own snapshot, allowing for rapid access to each individual song and all its associated work by simply changing snapshots, which can be done quickly utilizing the Snapshot List

Audio File Storage

Your audio files are stored in the folder interchange/{Session Name}/audiofiles/.  While this may seem unnecessarily complicated, it has an important function as a mechanism to allow convenient file interchange between ardour and other workstations.  In the future, Ardour will store standardized file formats such as AAF, AES31 and OpenTL in the interchange/{session name} folder. Simply grabbing the contents of the "interchange" folder will provide a cross-platform package that is suitable for collaboration, backup and long-term storage.

Session Templates

Once you have created a Session, you may wish to save the track/bus setup, options, and I/O information for the next project.  You can use Session Templates for this.  Session Templates are useful because they maintain all of the settings of a Session but do not store all of the audio files, resulting in a very small storage requirement.  See the chapter on saving a template

Cleaning up a Session with multiple Snapshots

Ardour has a function for cleaning out any audio files that are not currently referenced in a session.  This is a very important function as it is often inadvisable to store every last take and intermediate file because of storage limitations.  Ardour will find these unused files and delete them.

The presence of snapshots can cause confusion, as in "why didn’t cleanup do anything?" The answer is frequently that there are audio files referenced by a snapshot file.  Any reference to the file in _any_ of the snapshot files of a session will cause it to be kept.