pipewire-stream-volume-on-connect.c

// Our global variable
static int gotfirstvolumeupdate;

static void
set_volume(int dolock) {
    if (data.stream) {
        float plvol;
        float vol[SPA_AUDIO_MAX_CHANNELS];
        int i;

        if (plugin.has_volume) {
            plvol = get_player_volume_as_float();
        } else {
            plvol = 1.0f;
        }
        for (i = 0; i < get_player_channels(); i++) {
            vol[i] = plvol;
        }
        if (dolock) pw_thread_loop_lock(data.loop);
        pw_stream_set_control(data.stream, SPA_PROP_channelVolumes, get_player_channels(), vol, 0);
        if (dolock) pw_thread_loop_unlock(data.loop);
    }
}


static int _apply_volume(struct spa_loop *loop,
				  bool async,
				  uint32_t seq,
				  const void *_data,
				  size_t size,
				  void *user_data)
{
    set_volume(0);
    gotfirstvolumeupdate=1;
    trace("_apply_volume\n");
    return 0;
}

static void on_control_info(void *_data, uint32_t id, const struct pw_stream_control *control) {
    // We need to ignore the first volume update which is sent by pipewire to restore volume
    // This conflicts with the saved volume in the player
    // This is because the volume isn't updated when user adjusts volume while playback is stopped,
    // for this to work we would need to connect a dummy stream just to do this.
    if (!strcmp(control->name, "Channel Volumes")) {
        if (gotfirstvolumeupdate && plugin.has_volume) {
            deadbeef->volume_set_amp(control->values[0]);
        } else {
            trace("PipeWire: ignored volume update\n");
            // Instead we set our own volume here
            // Apparently we cannot call pw_stream_set_control() directly here or it may crash
            pw_loop_invoke(pw_thread_loop_get_loop(data.loop), _apply_volume, 1, NULL, 0, false, NULL);
        }
    }
}