I want to get access to the ALSA Simple Mixer interface, but rather than the 'default' sound device I want to target a specific USB sound device.
I'm at a loss how to refer to it... I am using a modified version of the code below but I have no idea what to replace the "card" and "selem_name" strings with. The device name? The 'hwX.Y' string?
And do I need to change the index#?
Too many variables to solve this by trial and error. Any hints appreciated!
void SetAlsaMasterVolume(long volume){ long min, max; snd_mixer_t *handle; snd_mixer_selem_id_t *sid; const char *card = "default"; const char *selem_name = "Master";
snd_mixer_open(&handle, 0); snd_mixer_attach(handle, card); snd_mixer_selem_register(handle, NULL, NULL); snd_mixer_load(handle);
snd_mixer_selem_id_alloca(&sid); snd_mixer_selem_id_set_index(sid, 0); snd_mixer_selem_id_set_name(sid, selem_name); snd_mixer_elem_t* elem = snd_mixer_find_selem(handle, sid);
snd_mixer_selem_get_playback_volume_range(elem, &min, &max); snd_mixer_selem_set_playback_volume_all(elem, volume * max / 100);
snd_mixer_close(handle);}