Change name of Application in Pipewire/Pulseaudio - c

Question

I am currently trying to build a very simple Audio-Tool, which needs to change its name in pavucontrol and qjackctl on runtime. When an Application produces Audio, its name is shown in pavucontrol. E.g. if I use firefox it is shown as "Firefox". I tried the most commonly suggested solutions: Editing argv and using prctl both did not succeed.
I also searched the pipewire documentation but I didn't find anything useful (but maybe I am just blind).
Is it even possible? From where does pipewire get the name of the Application?
Here is a little test-script in C with SDL2:
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <SDL2/SDL.h>
Uint8* audio_buffer = NULL;
Uint32 audio_length = 0;
void audio_callback(void* userdata, Uint8* stream, int n) {
memset(stream, 0, n);
}
int main(int argc, char** argv) {
SDL_Event evt;
SDL_AudioSpec desired;
SDL_Init(SDL_INIT_AUDIO|SDL_INIT_EVENTS);
SDL_LoadWAV("suil.wav", &desired, &audio_buffer, &audio_length);
desired.callback = audio_callback;
SDL_OpenAudio(&desired, NULL);
SDL_PauseAudio(0);
while (1) {
while (SDL_PollEvent(&evt)) {
switch (evt.type) {
case SDL_QUIT:
exit(EXIT_SUCCESS);
}
}
}
}
And a picture of what I would like to have changed on runtime:
(Note: The "test" would be the name in question.)
Disclaimer:
I'm not sure if this would maybe sdl-2 specific, so I added the SDL tag.

Answer 1

SDL's Pipewire backend grabs the application name in this block:
/* Get the hints for the application name, stream name and role */
app_name = SDL_GetHint(SDL_HINT_AUDIO_DEVICE_APP_NAME);
if (!app_name || *app_name == '\0') {
app_name = SDL_GetHint(SDL_HINT_APP_NAME);
if (!app_name || *app_name == '\0') {
app_name = "SDL Application";
}
}
...via the hint system:
SDL_HINT_APP_NAME:
/**
* \brief Specify an application name.
*
* This hint lets you specify the application name sent to the OS when
* required. For example, this will often appear in volume control applets for
* audio streams, and in lists of applications which are inhibiting the
* screensaver. You should use a string that describes your program ("My Game
* 2: The Revenge")
*
* Setting this to "" or leaving it unset will have SDL use a reasonable
* default: probably the application's name or "SDL Application" if SDL
* doesn't have any better information.
*
* Note that, for audio streams, this can be overridden with
* SDL_HINT_AUDIO_DEVICE_APP_NAME.
*
* On targets where this is not supported, this hint does nothing.
*/
#define SDL_HINT_APP_NAME "SDL_APP_NAME"
SDL_HINT_AUDIO_DEVICE_APP_NAME:
/**
* \brief Specify an application name for an audio device.
*
* Some audio backends (such as PulseAudio) allow you to describe your audio
* stream. Among other things, this description might show up in a system
* control panel that lets the user adjust the volume on specific audio
* streams instead of using one giant master volume slider.
*
* This hints lets you transmit that information to the OS. The contents of
* this hint are used while opening an audio device. You should use a string
* that describes your program ("My Game 2: The Revenge")
*
* Setting this to "" or leaving it unset will have SDL use a reasonable
* default: this will be the name set with SDL_HINT_APP_NAME, if that hint is
* set. Otherwise, it'll probably the application's name or "SDL Application"
* if SDL doesn't have any better information.
*
* On targets where this is not supported, this hint does nothing.
*/
#define SDL_HINT_AUDIO_DEVICE_APP_NAME "SDL_AUDIO_DEVICE_APP_NAME"
...and then passes the app name into Pipewire using PW_KEY_APP_NAME, here:
PIPEWIRE_pw_properties_set(props, PW_KEY_APP_NAME, app_name);
...where SDL's PIPEWIRE_pw_properties_set() is just a pointer to Pipewire's pw_properties_set().