How to programmatically change volume in Ubuntu
alsa, audio, gnome, python, ubuntu
Solution
Ubuntu uses pulseaudio as sounderver. It can be controlled from the command line using the `pactl` and `pacmd` utilities, for example:
pactl set-sink-volume 0 20%
would set the volume of the sink #0 to 20%.
see: `man pactl` and `pacmd help`
edit:
to avoid `-xx` being interpreted as command line option you must prefix it with `--`. That stops option parsing from that point:
pactl set-sink-volume 0 -- -20% # or:
pactl -- set-sink-volume 0 -20% # doesn't matter where the `--` goes
Problem
How do you programmatically change volume in Gnome on Ubuntu, either from the command line or an API (Python preferrably)? The only answers I found to similar questions use `amixer`, which seems to have no effect on Ubuntu 12.04. Running: ``` amixer set Headphone 10- ``` shows: ``` Simple mixer control 'Headphone',0 Capabilities: pvolume pswitch penum Playback channels: Front Left - Front Right Limits: Playback 0 - 115 Mono: Front Left: Playback 0 [57%] [-57.50dB] [on] Front Right: Playback 0 [57%] [-57.50dB] [on] ``` The x% changes each time I run it. Unfortunately, it has no effect on the actual volume. Eventually it says 0%, but volume is still at full blast. The other downside is I have to specify the exact active output device, which I might not know if there are multiple devices. For example, if I have a "Master" and "Headphone", how do I determine which one is the active device?