Plugin Development

A Quod Libet / Ex Falso Plugin is a simple python module or package which contains sub-classes of special plugin classes and is placed anywhere in ~/.config/quodlibet/plugins so it can be found by QL. These classes can provide special methods that get used by QL or can take action on certain events.

At the moment the following plugin classes exist:

Plugin Types

Event Plugins
  • Are instantiated as long as they are enabled or QL is running. They get notified when songs start, get added etc.
  • Can also (3.10+) listen to selection changes in the main songlist.
  • Example: Last.fm scrobbler that watches what you play and sends the information to last.fm.
Tag Editing Plugins
  • Can extend many parts of the tag editor.
  • Example: Title case your tags.
GStreamer Plugins
  • Can inject elements into the GStreamer pipeline and configure them on the fly.
  • Example: Tempo adjustment to play music/audio books faster.
Play Order: Shuffle Plugins
  • Can decide which song to play next or what happens if you select one.
  • Example: weighted shuffle, which prefers higher rated songs.
Play Order: Repeat Plugins:
  • How to repeat the songs
  • Example: repeat each song a set number of times
Songs Menu Plugins
  • Can be accessed through the play list context menu and get passed all selected songs.
  • Example: Album art search, to search album art for all selected songs.
Playlist Plugins
  • Similar to Songs Menu plugin, and in fact derived on the same base class
  • Can be accessed through the playlist context menu in the Playlist Browser
  • Example: remove duplicate songs from a playlist.
Cover Source Plugins
  • Fetch covers from external or local resources

Creating a new Plugin

  1. Create a file myplugin.py and place it under ~/.config/quodlibet/plugins (create the folder if needed). Alternatively (better), if you are running from source, put it in quodlibet/ext under a directory according to its plugin type.

  2. Write the following into the file:

    from quodlibet.plugins.events import EventPlugin

class MyPlugin(EventPlugin):
    PLUGIN_ID = "myplugin"
    PLUGIN_NAME = "My Plugin"

  3. Restart Quod Libet

  4. In Quod Libet open Music ⇒ Plugins and search the list for “My Plugin”

Tips:

  • The best way to find out what is possible is to read the documentation of the plugin base classes .
  • The easiest way to get started creating a new plugin is to look for existing plugins that do something similar to what you want.