writing about things, sometimes.


Written by Omar Polo on 20 September 2020 while listening to Kaerimichi.

2020/10/07 edit: I finally started to understand how interpolation in hydra works, so I’ve updated the code. (also converted to gemtext and some minor text changes)

Without a specific motivation, I wanted to try some Emacs music players. I briefly tried bongo, to finally set on EMMS, the Emacs Multi Media System.

One thing that I really appreciate about EMMS is how minimal it is: there is only one interface, the playlist buffer, and nothing else.

As emacs itself, emms is also very flexible, and thanks to this I believe I've found/build the “best music player ever” with it. If you use Emacs, I really encourage you to try EMMS out. The rest of this post is just bits of my configuration and some screenshots.


I'm not doing some fancy stuff to set it up. I'm just doing what suggested in the documentation:

(require 'emms-setup)

;; fancy
(setq emms-mode-line-format "「%s」")

Select a song

While you can easily select a song off a playlist in the “*EMMS Playlist*” buffer, I prefer to use selectrum to do it. The following code is what I ended up with.

(defun my/selectrum-emms ()
  "select and play a song from the current emms playlist."
    (let* ((selectrum-should-sort-p nil)
           (current-line-number (line-number-at-pos (point)))
           (lines (cl-loop
                   with min-line-number = (line-number-at-pos (point-min))
                   with buffer-text-lines = (split-string (buffer-string) "\n")
                   with lines = nil
                   for l in buffer-text-lines
                   for n = min-line-number then (1+ n)
                   do (push (propertize l' line-num n)
                   finally return (nreverse lines)))
           (selected-line (selectrum-read "song: " lines
                                          :default-candidate (nth (1- current-line-number) lines)
                                          :require-match t
                                          :no-move-default-candidate t)))
      (when selected-line
        (let ((line (get-text-property 0 'line-num selected-line)))
          (goto-line line)

Selecting a song from the current playlist with selectrum

Should be pretty easy to adapt it to use the standard completing-read.


I usually listen to music while doing various things, and I don't like the context switch from/to what I'm working on and the playlist buffer.

An hydra seems the best approach: you get “bindings that stick around” with just the little UI you need to manage your player. It's basically a mini-popup-ui for music controls. (In addition, I've recently discovered the hydra package, and I couldn't find an excuse not to build a hydra for EMMS).

An hydra for EMMS

I'm still pretty new to hydra, and I'm not 100% happy about how I'm doing the interpolation, but anyway, here's the code.

First, some helper functions

(defun my/tick-symbol (x)
  "Return a tick if X is true-ish."
  (if x "x" " "))

(defun my/emms-player-status ()
  "Return the state of the EMMS player: `not-active', `playing', `paused' or `dunno'.

Modeled after `emms-player-pause'."
  (cond ((not emms-player-playing-p)
         ;; here we should return 'not-active.  The fact is that
         ;; when i change song, there is a short amount of time
         ;; where we are ``not active'', and the hydra is rendered
         ;; always during that short amount of time.  So we cheat a
         ;; little.
         (let ((resume (emms-player-get emms-player-playing-p 'resume))
               (pause (emms-player-get emms-player-playing-p 'pause)))
           (cond (resume 'paused)
                 (pause  'playing)
                 (t      'dunno))))
        (t (let ((pause (emms-player-get emms-player-playing-p 'pause)))
             (if pause 'playing 'dunno)))))

(defun my/emms-toggle-time-display ()
  "Toggle the display of time information in the modeline"
  (interactive "")
  (if emms-playing-time-display-p

and then the full hydra

(defhydra hydra-emms (:hint nil)
%(my/emms-player-status) %(emms-track-description (emms-playlist-current-selected-track))

^Volume^     ^Controls^       ^Playback^              ^Misc^
_+_: inc     _n_: next        _r_: repeat one [% s(my/tick-symbol emms-repeat-track)]     _t_oggle modeline
_-_: dec     _p_: prev        _R_: repeat all [% s(my/tick-symbol emms-repeat-playlist)]     _T_oggle only time
^ ^          _<_: seek bw     _#_: shuffle            _s_elect
^ ^          _>_: seek fw     _%_: sort               _g_oto EMMS buffer
^ ^        _SPC_: play/pause
^ ^        _DEL_: restart
  ("+" emms-volume-raise)
  ("-" emms-volume-lower)
  ("n" emms-next)
  ("p" emms-previous)
  ("<" emms-seek-backward)
  (">" emms-seek-forward)
  ("SPC" emms-pause)
  ("DEL" (emms-player-seek-to 0))
  ("<backspace>" (emms-player-seek-to 0))
  ("r" emms-toggle-repeat-track)
  ("R" emms-toggle-repeat-playlist)
  ("#" emms-shuffle)
  ("%" emms-sort)
  ("t" (progn (my/emms-toggle-time-display)
  ("T" my/emms-toggle-time-display)
  ("s" my/selectrum-emms)
  ("g" (progn (emms)

  ("q" nil :exit t))

Tag support

I compiled the companion program “emms-print-metadata” to have tag support. Tags are read from a cache or using the helper program, so don't get frustrated if your tags aren't updated: clear the cache and re-import the music.

To use the helper program one needs to

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


EMMS should use mixerctl(1) to adjust the volume on OpenBSD. While it should work out of the box, mixerctl is considered too low level for normal user, and should be available only for root from 6.8 onward.

So, here's a emms-volume-sndioctl.el that works. It's basic, and should be probably polished a little bit more.

;;; emms-volume-sndioctl.el --- a mode for changing volume using sndioctl

;; This file is NOT part of EMMS.

(defun emms-volume-sndioctl-change (amount)
  "Change sndioctl output.level by AMOUNT."
  (message "Playback channels: %s"
             (when (zerop
                    (call-process "sndioctl" nil (current-buffer) nil
                                  (format "output.level=%s%f"
                                          (if (> amount 0) "+" "")
                                          (/ (float amount) 100))))
               (replace-regexp-in-string "\n" "" (buffer-string))))))

(provide 'emms-volume-sndioctl)

Leave it somewhere in your load-path, ~/.emacs.d/lisp/ is a good place, and then add to your configuration

(require 'emms-volume-sndioctl)
(setq-default emms-volume-change-function 'emms-volume-sndioctl-change)