[pulseaudio-discuss] How to control the right and left channel for a specific application using CLI ?

[Arun Raghavan]

On Tue, 3 Nov 2020, at 5:28 PM, 01ivier at labomedia.org wrote:
> Hello again,
> 
> I want to know if there is a way, still in command line, to control the 
> right and left volumes of an application.
> With Pulseaudio Volume Control, you can click on the lock icon related 
> to a launched application, and two sliders appear to do so.
> Is it possible in CLI ?
> 
> My goal is to run two applications on the same card, but to assign right 
> channel for one and left for the other.
> 
> Possible complication : the output of my application is in mono and with 
> Pulseaudio Volume Control I don't get the two sliders if I click on the 
> lock icon.

You can use pactl to do this:

  pactl set-sink-input <sink input index> <volume for channel 1> <volume for channel 2> ...

You can look up the sink input index and channel map for channel order with:

  pactl list sink-inputs

-- Arun