[pulseaudio-discuss] Changing Volume on Streams ( not Sinks )

[Georg Chini]

On 28.07.19 19:44, Brian Bulkowski wrote:
> I posted yesterday, twice, about how the "stream get sink id" was 
> going to solve my problems.
>
> In 10.0 ( the distro version on Debian Stretch on the Raspberry PI ), 
> the "sink ID" returned from that call is not a valid sink ID and 
> doesn't do anything good.
>
> I am hoping this call is more functional ( does anything functional ) 
> in later revs, so I'm onward to upgrading to 12.2 or similar, before 
> embarking on creating lots of extra Sinks in the configuration system.
>
> -brian

Hi Brian,

first, let me clarify the terminology pulseaudio is using:

- The term "sink" is used for for an audio output, for example your
speakers connected to your internal sound card or an USB or
Bluetooth device.

- The term "sink input" refers to an individual stream. A sink input
can be connected to a sink. Then the stream will play on your
output device.

To list sink inputs, the function pa_context_get_sink_input_info_list()
can be used. Then the volume can be changed with
pa_context_set_sink_input_volume().

For complete documentation see
https://freedesktop.org/software/pulseaudio/doxygen/

The functions I referenced above can be found at
https://freedesktop.org/software/pulseaudio/doxygen/introspect_8h.html

Regards
              Georg