1 Introduction

Emms is the Emacs Multi-Media System. Emms organizes playlists, allows browsing through track and album metadata, and plays files by calling external players.

This manual tries to be the definitive source of information about Emms, an online version of the manual is available at: http://www.gnu.org/software/emms/manual/.

The basic functionality of Emms consists of three parts: The core, the sources, and the players.

The core resides in emms.el, provides a simple playlist, and the basic functionality to use all the other features of Emms. It provides the common user commands and interfaces for other parts. It thinks in tracks, where a track is the combination of a type and a name - e.g. the track type ’file has a name that is the file name. Other track types are possible.

To get to tracks, the core needs sources. The file emms-source-file.el provides simple sources to interact with the file system.

When Emms finally has the sources in the playlist, it needs a player to play them. emms-player-simple.el defines a few useful players and provides a straightforward way of providing your own.

The Emms comes with many additional features to extend the functionality beyond the core.

The way Emms works is easy to customize with your own code or by using ‘M-x customize’ or by changing the variables directly.

2 Quickstart Guide

This chapter demonstrates how to setup Emms so that you can start listening to your music without having to read all of the documentation first. This is the tl;dr version of the manual.

The first thing to do is to load Emms via GNU ELPA. Invoke M-x list-packages and choose to install Emms.

If you are installing Emms manually, then start by telling Emacs where your copy of Emms is located. Let’s say you have it in ~/elisp/emms/. So add this line to your .emacs:

(add-to-list 'load-path "~/elisp/emms/lisp/")
(require 'emms-setup)

(More detailed information about installing Emms can be found in the installation chapter, See Installation.)

Either way, you are now ready to configure Emms. Your Emms config can be as simple as three lines. For example:

(emms-all)
(setq emms-player-list '(emms-player-vlc)
      emms-info-functions '(emms-info-native))

The function emms-all loads all of the stable features in Emms.

Emms can automatically generate that ‘setq’ statement for you based on which players and metadata readers you have installed on your system. Just invoke emms-setup-discover and answer a few questions.

The variable emms-player-list is a list of players that Emms should call to play your media. In this example we assume that you have VLC installed on your system. But if you use mpv or mplayer instead, just change emms-player-vlc to emms-player-mpv or emms-player-mplayer; you get the idea.

The variable emms-info-functions is a list of ways for Emms to read the metadata in your media files, so that Emms can display the song title, artist name, etc. emms-info-native is a metadata reader written entirely in Emacs Lisp, but there are also other backends which call external programs such as TinyTag, Taglib, Exiftool, and etc.

Reload your Emacs initialization file, or restart Emacs to let the changes have an effect.

Add all your music to a playlist by invoking M-x emms-add-directory-tree RET ~/my_music_directory/ RET. When you do this Emms will start reading metadata from the files and populating the cache. This may take a while.

When you are done, you can load the browser with M-x emms-browser, or view your playlist directly with M-x emms-playlist-mode-go (when in the playlist you can hit RET on a track to start playing it.)

Now you can start exploring Emms. It’s probably best to begin with the basic commands (see Basic Commands), the interactive playlists (see Interactive Playlists), and the browser (see The Browser).

More detail about setting up Emms can be found in the setup chapter, See Setup.

Need help? There are knowledgeable people on the #emacs channel on irc (irc.libera.chat), and Emms has a mailing list at emms-help@gnu.org.

3 Installation

Emms is available via GNU ELPA, which takes care of all of the following steps automatically.

If you are installing Emms manually, you need to put all the .el files of emms in a directory in your load-path. For example, if you put all those files into ~/elisp/emms/, then in your ~/.emacs, you should add:

(add-to-list 'load-path "~/elisp/emms/lisp/")

• Compiling Emms

EMACS=xemacs
SITEFLAG=-no-site-file

4 Setup

The ‘emms-setup’ feature is provided by the file emms-setup.el. It is essentially a collection of shortcuts for loading different Emms features quickly, but everything you can do with ‘emms-setup’ can also be done manually.

We use ‘emms-setup’ by calling one of the setup functions.

Function: emms-minimalistic ¶

An Emms setup script. Playlists and all the basics for playing media, but nothing else.

Function: emms-all ¶

An Emms setup script. Loads all the stable features which come with the Emms distribution.

‘emms-setup’ also comes with a convenience function to set a default list of media players.

Function: emms-default-players ¶

Set emms-player-list to emms-setup-default-player-list.

You can of course write your own Emms setup functions like the above by looking at the existing function definitions in emms-setup.el.

5 Configuration

This chapter discusses the configuration of Emms in more detail.

The following code fragment provides a minimal Emms setup without using the layer of ‘emms-setup’. It can maybe be used to better understand the internals of Emms. You can see how Emms needs to know about players (these are defined in ‘emms-player-simple’) and about sources for tracks (trivial file system based sources, such as this ‘emms-directory-tree’, are defined in ‘emms-source-file’).

(require 'emms-player-simple)
(require 'emms-source-file)
(require 'emms-source-playlist)
(setq emms-player-list '(emms-player-mpg321
                         emms-player-ogg123
                         emms-player-mplayer))

For a discussion on how to define additional players, see See Simple Players.

Much of the behaviour of Emms can be changed by setting variables. For example:

(setq emms-info-asynchronously nil)
(setq emms-playlist-buffer-name "*Music*")

The first setq turns off the asynchronous updating of info tags. The second sets the default name of the Emms playlist buffer.

Another way to change Emms variables is to use the M-x customize mechanism provided by Emacs.

• Finding files and speed
• Setup Examples

  ;; notifications
  (require 'emms-dbus)
  (emms-dbus-enable)
  ;; covers
  (setq emms-browser-covers #'emms-browser-cache-thumbnail-async)
  (setq emms-browser-thumbnail-small-size 64)
  (setq emms-browser-thumbnail-medium-size 128)
  ;; filters
  (emms-browser-make-filter "all" #'ignore)
  (emms-browser-make-filter "recent"
     (lambda (track) (< 30
        (time-to-number-of-days
  (time-subtract (current-time)
        (emms-info-track-file-mtime track))))))
  (emms-browser-set-filter (assoc "all" emms-browser-filters))
  ;; history
  (emms-history-load)
  ;; libre-fm
  (emms-librefm-scrobbler-enable)

  (setq-default
   emms-source-file-default-directory "/mnt/db/mediaCore/sound_music/"

   emms-source-playlist-default-format 'm3u
   emms-playlist-mode-center-when-go t
   emms-playlist-default-major-mode 'emms-playlist-mode
   emms-show-format "NP: %s"

   emms-player-list '(emms-player-mpv)
   emms-player-mpv-environment '("PULSE_PROP_media.role=music")
   emms-player-mpv-parameters '("--quiet" "--really-quiet" "--no-audio-display" "--force-window=no" "--vo=null"))

6 Getting Help

If you have a bug to report, need help, or wish to suggest a feature, please feel free to use the Emms mailing list. The address of the list is emms-help@gnu.org. To subscribe to it, visit http://lists.gnu.org/mailman/listinfo/emms-help.

If you are familiar with the Gmane service, there is a Gmane newsgroup which mirrors this mailing address at gmane.emacs.emms.user.

Emms also has a website at http://www.gnu.org/software/emms/.

7 Formats and Freedom

Emms is free software, but some of the file formats it can play carry restrictions, they are proprietary file formats. Proprietary software companies are pushing out audio and video formats which restrict when, where and how you can play them, and restrict developers from writing free software which interacts with them.

Restrictive file formats put the corporate bottom-line before the public interest.

Fortunately there are alternatives like Ogg. Ogg is a professional grade multimedia format. Ogg Vorbis is the compressed audio format (like MP3), and Ogg Theora is the video format. For more information, go to http://www.xiph.org/.

If you want to transcode audio into a lossless format, you can try FLAC (Free Lossless Audio Codec). FLAC stands out as the fastest and most widely supported lossless audio codec, and the only one that at once is non-proprietary, is unencumbered by patents and has the source code for a reference implementation freely available. For more information about FLAC, go to http://flac.sourceforge.net/.

8 Basic Commands

Before you can use the interface commands, you need a playlist to start with. The following commands allow you to add to the current playlist from different sources:

Note that the commands with the “emms-add-” prefix add the source to the playlist but do not start playing it immediately. Conversely, the commands with the “emms-play-” prefix begin playing the track immediately.

Function: emms-play-file file ¶

A source for a single file - either file, or queried from the user. If called with a prefix the file will be added like emms-add-file.

Function: emms-add-file file ¶

A source for a single file - either file, or queried from the user. If called with a prefix the file will be played like emms-play-file.

Function: emms-play-directory dir ¶

A source for a whole directory tree - either dir, or queried from the user.

Function: emms-add-directory dir ¶

A source for a whole directory tree - either dir, or queried from the user.

Function: emms-play-directory-tree dir ¶

A source for multiple directory trees - either dir, or the value of emms-source-file-default-directory.

Function: emms-add-directory-tree dir ¶

A source for multiple directory trees - either dir, or the value of emms-source-file-default-directory.

Function: emms-play-url url ¶

A source for an url - for example, for streaming over http, playing over sftp, or playing local files (with the “file://” scheme).

Function: emms-add-url url ¶

A source for an url - for example, for streaming over http, playing over sftp, or playing local files (with the “file://” scheme).

Function: emms-play-playlist playlist ¶

A source for the M3u or PLS playlist format from the file playlist.

Function: emms-add-playlist playlist ¶

A source for the M3u or PLS playlist format from the file playlist.

Function: emms-play-find dir regexp ¶

A source that will find files in dir or emms-source-file-default-directory which match regexp.

Function: emms-add-find dir regexp ¶

A source that will find files in dir or emms-source-file-default-directory which match regexp.

The basic functionality of Emms is just to play music without being noticed. It provides a few commands to skip the current track and such, but other than that it doesn’t show up. Emms provides the following basic user commands (which you might want to bind to keystrokes):

Function: emms-start ¶

Start playing the current playlist

Function: emms-stop ¶

Stop playing

Function: emms-next ¶

Start playing the next track in the playlist

Function: emms-previous ¶

Start playing previous track in the playlist

Function: emms-shuffle ¶

Shuffle the current playlist. This uses emms-playlist-shuffle-function.

Function: emms-sort ¶

Sort the current playlist. This uses emms-playlist-sort-function.

Function: emms-lock-queue ¶

Lock the current active playlist to its playlist. emms-playlist-sort-function.

Function: emms-unlock-queue ¶

Unlock the current active playlist from its playlist. emms-playlist-sort-function.

Function: emms-show &optional insertp ¶

Describe the current Emms track in the minibuffer. If insertp is non-nil, insert the description into the current buffer instead. This function uses emms-show-format to format the current track.

The command emms-show-all will pop up a window with the complete information about the track being played. emms-show-all is provided by emms-show-all.el, which is included in the ‘emms-all’ setup level. See See Setup.

9 The Core File

The core file emms.el provides the all basic functions for playing music, generating playlists and defining players.

• User Variables
• Hooks
• Core Functions

10 Sources

Sources allow Emms to add and play tracks. Emms comes with a number of sources of its own. Sources are designed so that creating new ones will be easy.

For examples of Emms sources for files and directories see emms-source-file.el.

User Option: emms-source-file-default-directory ¶

The default directory to look for media files.

Function: emms-play-find ¶

Play all files in emms-source-file-default-directory that match a specific regular expression.

Function: emms-source-file &optional file ¶

An Emms source for a single file - either file, or queried from the user.

Function: emms-source-files files ¶

An Emms source for a list of files.

Function: emms-source-directory &optional dir ¶

An Emms source for a whole directory tree - either dir, or queried from the user

Function: emms-source-directory-tree & optional dir ¶

An Emms source for multiple directory trees - either dir, or the value of emms-source-file-default-directory.

Function: emms-source-playlist file ¶

An Emms source for playlists. See emms-source-playlist-formats for a list of supported formats.

Function: emms-source-playlist-native file ¶

An Emms source for a native Emms playlist file.

Function: emms-source-playlist-m3u file ¶

An Emms source for an m3u playlist file.

Function: emms-source-playlist-pls file ¶

An Emms source for a pls playlist file.

Function: emms-source-find &optional dir regex ¶

An Emms source that will find files in dir or emms-source-file-default-directory that match regexp.

Function: emms-source-beets database filter sort ¶

An Emms source that will read a beets library database (requires Emacs to be built with SQLite support). With prefix argument filter, interactively filter the database. With a double (or more) prefix argument, also set sort interactively; otherwise use emms-source-beets-sort-columns. If database is omitted or nil, emms-source-beets-database is used.

Function: emms-source-file-directory-tree &optional dir ¶

Return a list of all files under dir which match regex.

Function: emms-play-dired ¶

Play all marked files of a dired buffer

Function: emms-add-dired ¶

Add all marked files of a dired buffer

Function: emms-source-file-regex ¶

Return a regexp that matches everything any player (that supports files) can play.

Function: emms-locate regexp ¶

Search for regexp and display the results in a locate buffer

11 Simple Players

Macro: define-emms-simple-player name types regex command &rest args ¶

Define a simple player. name is used to construct the name of the function like emms-player-name. types is a list of track types understood by this player. regex must be a regexp that matches the filenames the player can play. command specifies the command line argument to call the player and args are the command line arguments.

For a discussion on how to define new players see See New Player.

Function: emms-player-simple-stop ¶

Stop the currently playing process, if indeed there is one.

Function: emms-player-simple-start filename cmdname params ¶

Starts a process playing filename using the specified cmdname with the specified params.

Function: emms-player-simple-sentinel proc str ¶

Sentinel for determining the end of process for the process proc and the sentinel string str.

12 Playlists

Emms uses Emacs buffers to store the media tracks for playing. We call one such buffer a “playlist buffer” or an “Emms playlist buffer”. Emms then proceeds to play the media tracks in the buffer from top to bottom until the end of the playlist.

The name of the playlist buffer is defined in the variable emms-playlist-buffer-name and is set to be an invisible Emacs buffer by default. You can change to any name you want. For an example configuration see See Configuration.

You can create any number of playlist buffers you wish. At any time Emms has a single “current” buffer through which it proceeds track by track. A saved playlist can be added to the current buffer by calling M-x emms-add-playlist or M-x emms-play-playlist, which also plays the tracks immediately.

Function: emms-playlist-new &optional name ¶

Create a new playlist buffer. The buffer is named name, but made unique. name defaults to ‘emms-playlist-buffer-name’. If called interactively, the new buffer is also selected.

Function: emms-playlist-save &optional format file ¶

Store the current playlist to FILE as the type FORMAT. The default format is specified by emms-source-playlist-default-format.

The current Emms playlist buffer is stored in the variable emms-playlist-buffer.

13 Track Information

By default Emms will only list tracks as file names or URLs in playlists (see Playlists) and the browser (see The Browser). However, Emms can be configured to utilize so-called info methods to augment tracks with metadata information, such as artist name, track name, album title, and the like. We describe these methods and their use in this chapter.

Fundamentally, info methods are Emacs Lisp functions that are called for each track to provide information for that track. Current info methods in Emms are restricted to tracks that are files; they do not work with stream URLs (see Streaming Audio). Some of the methods require installation of some additional software that Emms can then call to read metadata from disk (see Metadata Utilities). Finally, some methods work only with a limited set of media file formats such as Ogg or MP3, while some methods support a wide variety of formats.

If caching is enabled (it is by default) then the metadata for each track will be stored in the cache for faster retrieval. That means if you change info method and want updated tracks, you will have to reset the cache M-x emms-cache-reset and then repopulate with M-x emms-add-directory-tree RET ~/Music/ RET or similar.

Automatic track information retrieval is enabled by default in the emms-all setup level (see Setup). That setup level configures Emms to use emms-info-native and emms-info-cueinfo methods, as they are the only methods that do not rely on additional software.

Here is a list of all info methods distributed with Emms and their software requirements:

emms-info-native

This method is implemented completely in Emacs Lisp and hence does not require any external software. It supports Ogg Vorbis, Opus, FLAC and MP3 files.

emms-info-tinytag

This method utilizes a small Python library tinytag. It supports MP3, Ogg Vorbis, Opus, MP4, M4A, FLAC, WMA and WAV formats.

emms-info-exiftool

This method calls exiftool utility written in Perl. It supports dozens of media file formats, far too many to list here.

emms-info-libtag

This method calls a small “shim” executable emms-print-metadata built around TagLib library. It supports MP3, Ogg Vorbis, Opus, FLAC, MPC, Speex, WavPack, TrueAudio, WAV, AIFF, MP4 and ASF formats.

emms-info-metaflac

This method calls metaflac utility. It works only with FLAC files.

emms-info-mp3info

This method calls mp3info utility. It works only with MP3 files that have older id3v1 tags.

emms-info-ogginfo

This method calls ogginfo utility. It supports Ogg Vorbis and Theora formats.

emms-info-opusinfo

This method calls opusinfo utility. It works only with Opus files.

emms-info-cueinfo

This is a special method that parses track information from an accompanying cue file for FLAC and APE files (see APE / FLAC Commands). It does not require any additional software.

To use any of the methods, add the method to emms-info-functions list. For example:

(require 'emms-info-native)
(add-to-list 'emms-info-functions 'emms-info-native)

You can also use a combination of format-specific tools if needed:

(require 'emms-info-mp3info)
(require 'emms-info-ogginfo)
(add-to-list 'emms-info-functions 'emms-info-mp3info 'emms-info-ogginfo)

In this case both emms-info-mp3info and emms-info-ogginfo will be called for each track.

There are a number of user variables which control the behavior of emms-info:

User Option: emms-info-auto-update ¶

Non-nil when Emms should update track information if the file changes. This will cause hard drive activity on track loading. If this is too annoying for you, set this variable to nil.

User Option: emms-info-asynchronously ¶

Non-nil when track information should be loaded asynchronously. This requires the feature later-do which is provided by the file later-do.el, which comes with Emms. See variable emms-later-do-batch for performance tweaking.

User Option: emms-info-functions ¶

A list of functions (info methods) which add information to tracks. Each function is called with a track as argument. If two info methods produce the same information (for example album name), the latter one takes precedence.

• Metadata Utilities
• Defining Info Methods

(require 'emms-info-tinytag)
(setq emms-info-functions '(emms-info-tinytag))

(require 'emms-info-exiftool)
(setq emms-info-functions '(emms-info-exiftool))

(require 'emms-info-libtag)
(setq emms-info-functions '(emms-info-libtag))

(require 'emms-info-metaflac)
(add-to-list 'emms-info-functions 'emms-info-metaflac)

(require 'emms-info-mp3info)
(add-to-list 'emms-info-functions 'emms-info-mp3info)

(require 'emms-info-ogginfo)
(add-to-list 'emms-info-functions 'emms-info-ogginfo)

(require 'emms-info-opusinfo)
(add-to-list 'emms-info-functions 'emms-info-opusinfo)

14 Interactive Playlists

Emms provides a visual, interactive playlist mode as well as the ability to use playlists without ever looking at then. This visual, interactive mode is called the ‘emms-playlist-mode’ and is defined in emms-playlist-mode.el.

The interactive playlist mode is enabled by default in the ‘emms-all’ setup level. For more information about Emms setup levels see See Setup.

Function: emms-playlist-mode-go ¶

Switch to the current emms-playlist buffer and use emms-playlist-mode.

If you wish to make this the default Emms playlist mode, add the following to your .emacs.

(setq emms-playlist-default-major-mode 'emms-playlist-mode)

The interactive playlist buffer shows the tracks in the current Emms playlist in the order in which they will be played. The current track will be highlighted.

When in the interactive playlist mode we can perform different actions on the current playlist.

a ¶

Add files in the playlist at point to the current playlist buffer. If we are in the current playlist, make a new playlist buffer and set it as current.

i ¶

Insert track at point into active playlist.

b ¶

Set the current playlist buffer.

n ¶

Start playing the next track in the playlist.

p ¶

Start playing the previous track in the playlist.

s ¶

Stop playing.

P ¶

Pause.

> ¶

Seek ten seconds forward.

< ¶

Seek ten seconds backward.

f ¶

Describe the currently playing track in the minibuffer.

c ¶

Display the current track in the center of the screen.

RET ¶

Start playing the track under point. Note that this is also available with <mouse-2>.

SPC ¶

Scroll up a near full page.

M-< ¶

Go to the first track in the playlist.

M-> ¶

Go to the last track in the playlist.

r ¶

Go to a randomly selected track in the playlist.

q ¶

Put the interactive playlist buffer at the end of the list of all buffers.

C-x C-s ¶

Save the current playlist buffer to a file. By default, Emms will ask you for confirmation before overwriting an existing playlist. You can silently overwrite existing playlist by setting emms-source-playlist-ask-before-overwrite to nil.

? ¶

Describe the mode.

C-i ¶

Shift the track at point up one line.

C-o ¶

Shift the track at point down one line.

M-n ¶

Switch to the next playlist buffer.

M-p ¶

Switch to the previous playlist buffer.

We can also edit the playlist using familiar GNU/Emacs commands:

C-k ¶

Remove the track under point from the playlist buffer. Also available using the d key.

C-y ¶

See the command yank

M-y ¶

See the command yank-pop.

C-j ¶

Insert a newline at point.

We can use the regular GNU/Emacs killing and yanking commands to move and copy tracks in between playlist buffers. We can use the same commands to insert arbitrary text into the playlist buffers together with the playlist tracks. Text which is not a track is ignored by the program and can therefore be used to include titles and annotations within the playlist.

15 Markable Playlists

The Markable Playlists provided by the file emms-mark.el are an alternative to the default interactive playlists, See Interactive Playlists. They allow marking tracks with keybindings familiar to users of dired.

To enable the Markable Playlists you have to add

(require 'emms-mark)

to your .emacs. Then you can activate emms-mark-mode by executing M-x emms-mark-mode in a playlist buffer. You can return to the default interactive playlist mode with M-x emms-mark-mode-disable.

If you wish to make this the default Emms playlist mode, add the following to your .emacs.

(setq emms-playlist-default-major-mode 'emms-mark-mode)

m ¶

Marks the current track and sets point one line forward. If a prefix argument ARG is given, it will mark the next ARG tracks and set point accordingly. A negative argument marks backward.

U ¶

Unmarks all tracks in the playlist.

t ¶

Toggles mark on the current track.

u ¶

Unmarks same way as emms-mark-forward marks.

% m ¶

Marks all tracks in the playlist matching the given regular expression. A prefix argument means to unmark them instead.

When tracks are marked you can operate on them:

D ¶

Deletes the marked tracks from the playlist.

K ¶

Deletes the marked tracks from the playlist and places them in the kill-ring, so that you can yank in into another playlist.

W ¶

Adds the marked tracks to the kill-ring, so that you can yank them into another playlist.

emms-mark is also intent to provide a way for user to select tracks for other command to operate on them. Currently, emms-tag-editor.el uses the emms-mark to edit the tags of selected tracks. Two functions are useful for the elisp programer to handle marked tracks.

Function: emms-mark-do-with-marked-track ¶

This function take a function to perform on all marked tracks. A optional argument ‘move-flag’ to tell the function to move forward line after calling given function. If the given function didn’t change position, the second argument should set to non-nil.

Function: emms-mark-mapcar-marked-track ¶

This function is very similar to ‘emms-mark-do-with-marked-track’ except it collects result of given function (that’s why named with ‘mapcar’).

16 Extending Emms

Emms introduces a high abstraction layer for playing music so you can customise it to your needs.

• New Player
• Simple Player for ‘play’
• More Complex Player

(require 'emms-player-simple)
(define-emms-simple-player play '(file) "\\.wav$" "play")

(require 'emms-player-simple)

(define-emms-simple-player play
                           '(file)
                           "\\artist-*.wav$"
                           "play"
                           "--volume=100")

(define-emms-player "emms-mpg321-remote"
  :start 'emms-mpg321-remote-start
  :stop 'emms-mpg321-remote-stop
  :playablep 'emms-mpg321-remote-playable-p)

(defun emms-mpg321-remote-start ()
  (unless (get-process ``mpg321-remote'')
    (setq emms-mpg321-remote-process
          (start-process "mpg321-remote-process"
                         "*mpg321*" "mpg321" "-R" "abc"))
  (process-send-string "mpg321-remote-process"
                       (concat "l " (emms-track-name track)))
  (set-process-filter emms-mpg321-remote-process 'emms-mpg321-remote-filter)))

(defun emms-mpg321-remote-filter (process output)
  (when (string-match "(at-sign)P 0" output)
    (emms-mpg321-remote-stop)))

(defun emms-mpg321-remote-stop ()
  (unless emms-playlist
    (process-send-string "mpg321-remote-process" "Q\n"))

(defun emms-mpg321-remote-playablep (track)
       "Return non-nil when we can play this track."
       (and (emms-track-file-p track)

17 The Browser

The Browser allows you to browse the metadata cache and add tracks to your playlist. It includes a powerful interactive mode.

The Browser is defined in emms-browser.el and is included in the emms-all setup level. For more information about Emms setup levels see See Setup.

You can also manually add the Browser to your Emms setup by loading it explicitly with:

(require 'emms-browser)

To be properly useful, you should do M-x emms-add-directory-tree to all the files you own at least once so that the cache is fully populated.

• Browser Interface
• Filtering Tracks
• Displaying Covers
• Changing Looks

(emms-browser-make-filter "all" 'ignore)

(emms-browser-set-filter (assoc "all" emms-browser-filters))

(emms-browser-make-filter
 "all-files" (emms-browser-filter-only-type 'file))

(emms-browser-make-filter
 "80s" (emms-browser-filter-only-dir "~/Mp3s/80s"))

(emms-browser-make-filter
 "last-month" (emms-browser-filter-only-recent 30))

(emms-browser-make-filter "not-played"
 (lambda (track)
  (not (funcall (emms-browser-filter-only-recent 365) track))))

(emms-browser-make-filter
 "all"
 (lambda (track)
   (or
    (funcall (emms-browser-filter-only-type 'file) track)
    (not (funcall
          (emms-browser-filter-only-dir "~/Media/pending") track)))))

(setq emms-browser-default-covers
  (list "/path/to/cover_small.jpg" nil nil)

(defadvice emms-browser-next-mapping-type
                                (after no-album (current-mapping))
  (when (eq ad-return-value 'info-album)
    (setq ad-return-value 'info-title)))

(defun toggle-album-display ()
  (if (string= emms-browser-current-filter-name "singles")
      (ad-activate 'emms-browser-next-mapping-type)
    (ad-deactivate 'emms-browser-next-mapping-type)))

(add-hook 'emms-browser-filter-changed-hook 'toggle-album-display)

(defvar emms-browser-info-title-format "%i%n")
(defvar emms-browser-playlist-info-title-format
  emms-browser-info-title-format)

18 Sorting Playlists

The ‘emms-playlist-sort’ module, defined in the emms-playlist-sort.el package provides functions for sorting Emms playlists, as well as keyboard shortcuts for invoking the functions in the playlist buffer. Most of the functions will sort in reverse order if the command is preceded by a prefix. ‘emms-playlist-sort’ can be loaded by invoking:

(require 'emms-playlist-sort)

Function: emms-playlist-sort-by-info-artist ¶

Sort by artist name.

Function: emms-playlist-sort-by-info-albumartist ¶

Sort by albumartist name.

Function: emms-playlist-sort-by-play-count ¶

Sort by number of times the track has been played.

Function: emms-playlist-sort-by-info-album ¶

Sort by album name.

Function: emms-playlist-sort-by-last-played ¶

Sort by time the track was played last.

Function: emms-playlist-sort-by-info-title ¶

Sort by track title.

Function: emms-playlist-sort-by-file-extension ¶

Sort by filename extension.

Function: emms-playlist-sort-by-info-performer ¶

Sort by performer name.

Function: emms-playlist-sort-by-info-year ¶

Sort by year.

Function: emms-playlist-sort-by-info-note ¶

Sort by track notes.

Function: emms-playlist-sort-by-info-composer ¶

Sort by composer.

Function: emms-playlist-sort-by-name ¶

Sort by track name.

Function: emms-playlist-sort-by-file-mtime ¶

Sort by file mtime.

Function: emms-playlist-sort-by-random ¶

Sort randomly. Alias for ‘emms-shuffle’.

Function: emms-playlist-shuffle ¶

Alias for ‘emms-playlist-sort-by-random’ and ‘emms-shuffle’.

19 Persistent Playlists

The Emms module emms-history.el makes playlists persistent over emacs sessions. To make use of this feature put this into your ~/.emacs.

(require 'emms-history)

When you kill emacs all playlists will be saved in the file given by the variable:

User Option: emms-history-file ¶

The file to save playlists in. It defaults to "~/.emacs.d/emms-history".

After you started up emacs again, you can restore all saved playlists with this function.

Function: emms-history-load ¶

Restore all playlists in ‘emms-history-file’.

If that should be done automatically on each startup, put these lines into your ~/.emacs.

(require 'emms-history)
(emms-history-load)

Normally emms-history only restores playlists. If you want it to start playback afterwards, you can tweak this variable.

User Option: emms-history-start-playing ¶

If non-nil emms starts playing the current track after ‘emms-history-load’ was invoked. The default value is nil.

20 Editing Tracks

Using emms-tag-editor.el, emms can set tag informations of tracks and write them back to the file with the help of external programs, such as ‘mid3v2’ and ‘vorbiscomment’.

Use the keybinding E to edit the tags of track under point in the playlist or all marked tracks (see Markable Playlists for how to mark tracks). The track’s tag informations are listed in a special buffer ‘*Emms-TAGS*’ in text format. Field names are marked in bold face and are not editable. Any tag information is placed behind an equal sign and is changable. A special field ‘name’ is the track’s file name. If any change is made in this field, the track’s file will be renamed to the new name. When you finished editing the tag infos use C-c C-c (which calls emms-tag-editor-submit-and-exit) to submit the changes and close the ‘*Emms-TAGS*’ buffer.

There are a few commands to perform changes on all tracks.

Function: emms-tag-editor-set-all tag value ¶

Set TAG to VALUE in all tracks.

If transient-mark-mode is turned on, you can apply the command to a selected region.

If ‘transient-mark-mode’ is on and the mark is active, the changes will only take effect on the tracks in the region.

Function: emms-tag-editor-replace-in-tag tag from to ¶

Query and replace text in selected TAG.

For example, if the info-title tag is selected, then only perform replacement in title tags.

If ‘transient-mark-mode’ is on and the mark is active, the changes will only take effect on the tracks in the region.

Function: emms-tag-editor-transpose-tag tag1 tag2 ¶

Transpose value of TAG1 and TAG2.

If ‘transient-mark-mode’ is on and the mark is active, the changes will only take effect on the tracks in the region.

Function: emms-tag-editor-submit arg ¶

Make modified tags take affect.

With prefix argument, bury the tag edit buffer.

If you want to extend the tag editor to work with file formats other than ‘mp3’ and ‘ogg’, have a look at these variables.

Variable: emms-tag-editor-formats ¶

This variable determine how to insert track fields to ‘emms-tag-editor-edit-buffer’. Emms tag info editable fields is usually determined by the extension of track name. The variable ‘emms-tag-editor-tags’ contains all tags that emms track may have. A single charactar is assigned to the tag to make the ‘emms-tag-editor-formats’ easier to generate.

Variable: emms-tag-editor-tagfile-functions ¶

To write tags to track file, an extern program should specified in this variable.

Renaming Files

The tag editor is also capable to rename the file of the track at point or all files of the marked tracks according to the value this variable.

User Option: emms-tag-editor-rename-format ¶

When ‘emms-tag-editor-rename’ is invoked the track’s file will be renamed according this format specification. The file extension will be added automatically.

It uses the format specs defined in emms-tag-editor-tags.

The default value is "%a - %l - %n - %t", so that files are named

<Artist> - <Album> - <Tracknumber> - <Title>.<extension>

after renaming.

To perform the renaming put point on the track you want to rename or mark some tracks. Then hit R which calls this function:

Function: emms-tag-editor-rename ¶

Rename the file corresponding to track at point or all marked tracks according to the value of emms-tag-editor-rename-format.

21 Emms Mode Line

We can display information about the currenty playing track on the Emacs mode line using the package ‘emms-mode-line’ which is provided by the file emms-mode-line.el.

To activate this feature invoke:

(require 'emms-mode-line)
(emms-mode-line 1)

It is also possible to display the amount of time a track has been playing. This feature is defined in the ‘emms-playing-time’ package which is provided by the file emms-playing-time.el.

To use this feature invoke:

(require 'emms-playing-time)
(emms-playing-time 1)

A graphical icon can be displayed in the modeline when Emms is playing. This feature is provided by emms-mode-line-icon.el. To enable invoke the following and make sure that emms-mode-line-icon-enabled-p is set to a non-nil value:

(require emms-mode-line-icon)

Note: ‘(emms-playing-time -1)’ will disable emms-playing-time module completely, and is not recommended. (since some other emms modules may rely on it)

Instead, to toggle displaying playing time on mode line, one could call ‘emms-playing-time-enable-display’ and ‘emms-playing-time-disable-display’."

Function: emms-playing-time-enable-display ¶

Display playing time on mode line.

Function: emms-playing-time-disable-display ¶

Remove playing time from mode line.

22 Limiting

The package ‘emms-playlist-limit’, provided by emms-playlist-limit.el, allows creating a new playlist derived from the playlist in the current buffer. For instance, it is possible to create a new playlist containing only a certain artist or genre from the playlist in the current buffer.

If the playlist in the current buffer is the emms current playlist then the derived playlist becomes current.

/ a ¶

Create a new playlist buffer and populate it with tracks whose artist info field matches the given regular expression (default: the artist info field of the track at point).

/ A ¶

Create a new playlist buffer and populate it with tracks whose album artist info field matches the given regular expression (default: the album artist info field of the track at point).

/ b ¶

Create a new playlist buffer and populate it with tracks whose album info field matches the given regular expression (default: the album info field of the track at point).

/ c ¶

Create a new playlist buffer and populate it with tracks whose composer info field matches the given regular expression (default: the composer info field of the track at point).

/ d ¶

Create a new playlist buffer and populate it with tracks whose track description matches the given regular expression (default: the track description of the track at point).

/ g ¶

Create a new playlist buffer and populate it with tracks whose genre info field matches the given regular expression (default: the genre info field of the track at point).

/ n ¶

Create a new playlist buffer and populate it with tracks whose name matches the given regular expression (default: the name of the track at point).

/ p ¶

Create a new playlist buffer and populate it with tracks whose performer info field matches the given regular expression (default: the performer info field of the track at point).

/ t ¶

Create a new playlist buffer and populate it with tracks whose title info field matches the given regular expression (default: the title info field of the track at point).

/ y ¶

Create a new playlist buffer and populate it with tracks whose year info field matches the given regular expression (default: the year info field of the track at point).

/ / ¶

Switch to the original playlist buffer (if it still exists).

23 Music Player Daemon

Emms provides an interface to the Music Player Daemon(MusicPD) software. The package is called ‘emms-player-mpd’ and is provided by the file emms-player-mpd.el.

The advantages of using MusicPD as an Emms backend include the following.

• minimal CPU usage
• fast access of track information
• optional crossfade

Setup

To load ‘emms-player-mpd’ invoke:

(require 'emms-player-mpd)

Set the variables emms-player-mpd-server-name and emms-player-mpd-server-port to the location and port (respectively) of your MusicPD server. For example:

(setq emms-player-mpd-server-name "localhost")
(setq emms-player-mpd-server-port "6600")

If your MusicPD setup requires a password, you will to set emms-player-mpd-server-password as follows.

(setq emms-player-mpd-server-password "mypassword")

To get track information from MusicPD, invoke the following:

(add-to-list 'emms-info-functions 'emms-info-mpd)

Adding ‘emms-player-mpd’ to your Emms player list is accomplished by invoking:

(add-to-list 'emms-player-list 'emms-player-mpd)

Unless your MusicPD is configured to use absolute file names, you must set the emms-player-mpd-music-directory variable to the value of ’music_directory’ in your MusicPD configuration. There are additional options available as well, but the defaults should be sufficient for most uses.

Once you’ve done the above, run the M-x emms-cache-set-from-mpd-all command to fill the Emms cache with the contents of your MusicPD database. The music in your MusicPD database should then be accessible via the Emms browser.

You can set emms-player-mpd-sync-playlist to nil if your master Emms playlist contains only stored playlists.

In order for Emms to synchronize track information correctly with MusicPD, you must set the MusicPD server runtime ’consume’ option to ’off’. This can be accomplished with the mpc command line MusicPD client using the command mpc consume off.

Commands provided

Function: emms-player-mpd-connect ¶

Connect to MusicPD and retrieve its current playlist. Afterward, the status of MusicPD will be tracked.

Function: emms-player-mpd-disconnect ¶

Terminate the MusicPD client process and disconnect from MusicPD.

Function: emms-player-mpd-show &optional insertp ¶

Describe the current Emms track in the minibuffer. If INSERTP is non-nil, insert the description into the current buffer instead. This function uses emms-show-format to format the current track. It differs from emms-show in that it asks MusicPD for the current track, rather than Emms.

Updating the MusicPD database

Function: emms-player-mpd-update-directory dir ¶

Cause the tracks in DIR to be updated in the MusicPD database.

Function: emms-player-mpd-update-all ¶

Cause all tracks in the MusicPD music directory to be updated in the MusicPD database.

emms-cache.el integration

Function: emms-cache-set-from-mpd-directory dir ¶

Dump all MusicPD data from DIR into the Emms cache. This is useful to do when you have recently acquired new music.

Function: emms-cache-set-from-mpd-all ¶

Dump all MusicPD data into the Emms cache. This is useful to do once, just before using emms-browser.el, in order to prime the cache.

emms-volume.el integration

To activate this, add the following to your .emacs.

(require 'emms-volume)
(setq emms-volume-change-function 'emms-volume-mpd-change)

24 Lyrics

We can display the lyrics of a song in time with the music using the ‘emms-lyrics’ package provided by the file emms-lyrics.el.

The lyrics files should have the extention “.lrc”, and can be placed under either the same directory as the music files or emms-lyrics-dir.

To add this feature we invoke:

(require 'emms-lyrics)
(emms-lyrics 1)

Synchronized lyrics files can be obtained manually from various sources, or fetched automatically for new tracks from an LRCLIB server (https://lrclib.net) by adding the following function to emms-track-initialize-functions:

Function: emms-lyrics-lrclib-get &optional track force interactive ¶

Search for synchronized lyrics for track through LRCLIB’s API. If track is omitted or nil, use the selected track in the current playlist. When used as a track initialization function, track is set to the track being initialized. The lyrics are saved in an “.lrc” file alongside the track, unless the file already exists (in which case the search isn’t performed). When called interactively (non-nil interactive), display informative messages, and with prefix argument force, ask to overwrite existing “.lrc” files.

There are a number of variables we can set to define the way that ‘emms-lyrics’ behaves, we can set these directly or by using the Customize feature in Emacs.

User Option: emms-lyrics-display-on-minibuffer ¶

If non-nil, display lyrics on minibuffer.

User Option: emms-lyrics-display-on-modeline ¶

If non-nil, display lyrics on modeline.

User Option: emms-lyrics-dir ¶

Local lyrics repository. emms-lyrics-find-lyric will look for lyrics in current directory(i.e., same as the music file) and this directory.

User Option: emms-lyrics-display-format ¶

Format for displaying lyrics. "%s" will be replaced by the lyrics string.

User Option: emms-lyrics-coding-system ¶

Coding system used in the output of lyrics.

User Option: emms-lyrics-scroll-p ¶

Non-nil value will enable lyrics scrolling.

User Option: emms-lyrics-scroll-timer-interval ¶

Interval between scroller timers. The shorter, the faster.

User Option: emms-lyrics-lrclib-url ¶

Base URL for LRCLIB API requests.

We can control ‘emms-lyrics’ with the help of the following functions:

Function: emms-lyrics-start ¶

Start displaying lyrics.

Function: emms-lyrics-stop ¶

Stop displaying lyrics.

Function: emms-lyrics-toggle-display-on-minibuffer ¶

Toggle display lyrics on minibufer.

Function: emms-lyrics-toggle-display-on-modeline ¶

Toggle display lyrics on mode line.

Function: emms-lyrics-enable ¶

Enable displaying Emms lyrics.

Function: emms-lyrics-disable ¶

Disable displaying Emms lyrics.

Function: emms-lyrics-toggle ¶

Toggle displaying Emms lyrics.

25 Volume

We can use the ‘emms-volume’ package, as provided by the emms-volume.el file, to manipulate the volume.

User Option: emms-volume-change-amount ¶

The amount to use when raising or lowering the volume using the emms-volume interface.

This should be a positive integer.

Function: emms-volume-raise ¶

Increase the volume.

Function: emms-volume-lower ¶

Decrease the volume.

If you feel like binding those two functions to global keys — don’t do it or you’ll miss the convenience of ‘emms-volume-minor-mode’. Instead, bind the following two commands to some keys that you like.

Function: emms-volume-mode-plus ¶

Raise volume and enable or extend the ‘emms-volume-minor-mode’ timeout.

Function: emms-volume-mode-minus ¶

Lower volume and enable or extend the ‘emms-volume-minor-mode’ timeout.

Example:

(global-set-key (kbd "C-c +") 'emms-volume-mode-plus)
(global-set-key (kbd "C-c -") 'emms-volume-mode-minus)

Whenever you use one of these keys or call these functions with M-x, Emms will be put into ‘emms-volume-minor-mode’ for a short period defined by ‘emms-volume-mode-timeout’.

User Option: emms-volume-mode-timeout ¶

The timeout in amount of seconds used by ‘emms-volume-minor-mode’.

In this interval you can raise/lower the volume simply by pressing + or -, which will also reset the timer to its initial value. So instead of pressing C-c + six times to increase volume by six steps of emms-volume-change-amount, you would simply type C-c + + + + + +.

Emms can change volume with amixer, mpd, PulseAudio and mixerctl out of the box, see emms-volume-change-function.

26 Streaming Audio

Emms is a great way to play streaming audio and internet radio. It is possible to add streaming playlists and URLs to any playlist, but Emms also comes with a built-in, eclectic list of streaming audio stations. ¹

The emms-streams.el package provides the command emms-streams.

Invoking emms-streams will pull up an Emms playlist buffer and populate it with the built-in list of streaming audio sources.

If you are using the mpv player, defined by emms-player-mpv.el, then you can display the currently streaming track title (if the station provides that information) by configuring:

  (customize-set-variable 'emms-player-mpv-update-metadata t)

27 APE / FLAC Commands

Often, a single APE or FLAC file contains a complete album. We can still play next or previous track in the album with the help of emms-cue.el package, provided there is a corresponding cue sheet file. This package also defines emms-info-cueinfo for retreiving the track information for APE / FLAC itself.

To load emms-cue.el:

(require 'emms-cue)
(add-to-list 'emms-info-functions 'emms-info-cueinfo)

Function: emms-cue-next ¶

Play next track from .cue file

Function: emms-cue-previous ¶

Play previous track from .cue file

28 Bookmarks

Emms can save a “temporal bookmark” in a media file via emms-bookmarks. The file emms-bookmarks.el provides the package emms-bookmarks.

While some media is playing, invoking M-x emms-bookmarks-add will first pause the playback and then prompt for a name describing the bookmark. Tracks can have multiple bookmarks associated with them.

To jump to the next and previous bookmarks in the current track invoke M-x emms-bookmarks-next and M-x emms-bookmarks-prev respectively.

To clear all of the bookmarks for the current track invoke M-x emms-bookmarks-clear.

29 Managing Playlists

Emms can have multiple playlists, since a playlist is just another buffer with a list of tracks. You can manage multiple playlists using ‘emms-metaplaylist-mode’, provided by the file emms-metaplaylist-mode.

Start the playlist manager with M-x emms-metaplaylist-mode-go. The playlist manager will list the playlists and mark the current one. The following commands are available:

RET ¶

Make the buffer at point the Emms playlist buffer and switch to it.

+

V ¶

Visit the playlist at point.

SPC ¶

Make the buffer at point the Emms playlist buffer (but do not switch to it).

n ¶

Move point to the next playlist.

p ¶

Move point to the previous playlist.

g ¶

Update the playlist manager buffer.

C ¶

Create a new Emms playlist buffer.

C-k ¶

Kill the Emms playlist buffer at point.

c ¶

Move point to the current playlist buffer.

q ¶

Kill the playlist manager.

30 GNU FM

GNU FM is free software for running music community websites. It was created for the music community site, Libre.fm.

Emms can send track information, and stream music from GNU FM servers using emms-librefm-scrobbler.el and emms-librefm-stream.el, respectively.

Emms is configured by default to use Libre.fm, but can work with any GNU FM server by configuring the variable emms-librefm-scrobbler-handshake-url to the URL of the GNU FM server.

The recommended way of providing your credentials to the GNU FM server is by using an authinfo file. Add authentication to your auth-info file, typically ~/.authinfo.gpg, as:

machine libre.fm login USERNAME password PASSWORD

If you are using some other server than libre.fm, change “‘libre.fm’” to match emms-librefm-scrobbler-handshake-url.

Alternatively, you can save the password in plaintext in your init-file by setting these variables:

(setq emms-librefm-scrobbler-username "USERNAME"
      emms-librefm-scrobbler-password "PASSWORD")

• Uploading Track Information
• GNU FM Streaming

(require 'emms-librefm-scrobbler)

(require 'emms-librefm-stream)

31 Listenbrainz

Listenbrainz offers an alternative store of listening habits using information sent by the Emms.

To use this service, you will need to obtain a user token from https://listenbrainz.org/settings/. You should store this token in ~/.authinfo.gpg or an equivalent file understood by auth-source with a line like this:

machine api.listenbrainz.org password 0abc1de2-245-67fa-8906b-bc123d4dbdaa

Alternatively, you can store the token in plain-text in your init file by setting the variable emms-listenbrainz-scrobbler-token:

(setq emms-listenbrainz-scrobbler-token "0abc1de2-245-67fa-8906b-bc123d4dbdaa")

Once this is done, you can load the feature with

(require 'emms-listenbrainz-scrobbler)

Enable uploading the details of the tracks Emms plays to the listenbrainz server with emms-listenbrainz-scrobbler-enable. The track’s details will be uploaded to the server when the track’s playback ends. You can disable this behavior with emms-listenbrainz-scrobbler-disable.

32 D-Bus

Emms can provide an MPRIS interface which allows it to be controlled over D-Bus.

To enable this, first load the feature:

(require 'emms-mpris)

and then turn it on with emms-mpris-enable. You can turn it off with emms-mpris-disable.

At present, the Emms implementation of the MPRIS specification is not complete: changing the volume is not currently supported.

33 GNU Free Documentation License

Copyright © 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.

0. PREAMBLE

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   This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

   We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

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   Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

   The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work’s title, preceding the beginning of the body of the text.

   A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

   The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

2. VERBATIM COPYING

   You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

   You may also lend copies, under the same conditions stated above, and you may publicly display copies.

3. COPYING IN QUANTITY

   If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

   If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

   If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

   It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

4. MODIFICATIONS

   You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

   1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
   2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
   3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
   4. Preserve all the copyright notices of the Document.
   5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
   6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
   7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document’s license notice.
   8. Include an unaltered copy of this License.
   9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
   10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
   11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
   12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
   13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
   14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
   15. Preserve any Warranty Disclaimers.

   If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

   You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

   You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

   The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

5. COMBINING DOCUMENTS

   You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

   The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

   In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”

6. COLLECTIONS OF DOCUMENTS

   You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

   You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

   A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

   If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

8. TRANSLATION

   Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

   If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

9. TERMINATION

   You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

10. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

• ADDENDUM: How to use this License for your documents

  Copyright (C)  year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.2
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.

    with the Invariant Sections being list their titles, with
    the Front-Cover Texts being list, and with the Back-Cover Texts
    being list.