Make a new notification with sound icon and bar

Probably this question has already been answered somewhere, but I could not find it.

The situation: I am on Ubuntu 15.10, on a laptop.
I have a secondary bluetooth speakers system, on which I redirect some output (mainly the music).

I can control the volume with pactl with

pactl -- set-sink-volume bluez_sink.00_18_91_65_D8_6D +5%
pactl -- set-sink-volume bluez_sink.00_18_91_65_D8_6D -5%

and having associated this to some keyboard shortcuts I can increase and decrease it like if it'd be local.

This works fine but, unlike for the main output (the internal audio card), using this command does not produce a notification with the actual volume level.

So, how can I produce the notification with the changing icon and the bar for the volume, like Ubuntu does?

Should I use notify-send? With which parameters?
It should not be a "normal" notification, because it has to "stick" there when the volume changes and just adapt the bar...

Solution 1:

Yep, it should be special notification:

gdbus call --session --dest org.freedesktop.Notifications \
  --object-path /org/freedesktop/Notifications \
  --method org.freedesktop.Notifications.Notify \
    'gnome-settings-daemon' \
    0 \
    'notification-audio-volume-medium' \
    ' ' \
    '' \
    [] \
    "{'x-canonical-private-synchronous': <'volume'>, 'value': <24>}" \
    1

1. Found by watching dbus-monitor:

   method call time=1447796042.858910 sender=:1.11 -> destination=:1.96 serial=216 path=/org/freedesktop/Notifications; interface=org.freedesktop.Notifications; member=Notify
      string "gnome-settings-daemon"
      uint32 0
      string "notification-audio-volume-medium"
      string " "
      string ""
      array [
      ]
      array [
         dict entry(
            string "x-canonical-private-synchronous"
            variant             string "volume"
         )
         dict entry(
            string "value"
            variant             int32 48
         )
      ]
      int32 -1
   

2. Then write my own call using:

   • gdbus following this post How to pass a{sv} arguments to gdbus?
   • Or if you want python, this well explained post: How to read dbus-monitor output?. Even it has same sound notification as a showcase.

3. Icons available are:

   find /usr/share/notify-osd/icons/hicolor/scalable/status/ -name "notification-audio-volume-*" -exec basename {} .svg \;

   notification-audio-volume-low
   notification-audio-volume-off
   notification-audio-volume-medium
   notification-audio-volume-muted
   notification-audio-volume-high