libobs: Add obs_volmeter_get_cur_db function

libobs/obs-audio-controls.c

@@ -804,3 +804,27 @@ void obs_volmeter_remove_callback(obs_volmeter_t *volmeter,
 	da_erase_item(volmeter->callbacks, &cb);
 	pthread_mutex_unlock(&volmeter->callback_mutex);
 }
+
+float obs_volmeter_get_cur_db(enum obs_fader_type type, const float def)
+{
+	float db;
+
+	switch(type) {
+	case OBS_FADER_CUBIC:
+		db = cubic_def_to_db(def);
+		break;
+	case OBS_FADER_IEC:
+		db = iec_def_to_db(def);
+		break;
+	case OBS_FADER_LOG:
+		db = log_def_to_db(def);
+		break;
+	default:
+		goto fail;
+		break;
+	}
+
+	return db;
+fail:
+	return -INFINITY;
+}

libobs/obs-audio-controls.h

@@ -251,6 +251,8 @@ EXPORT void obs_volmeter_add_callback(obs_volmeter_t *volmeter,
 EXPORT void obs_volmeter_remove_callback(obs_volmeter_t *volmeter,
 		obs_volmeter_updated_t callback, void *param);
 
+EXPORT float obs_volmeter_get_cur_db(enum obs_fader_type type, const float def);
+
 #ifdef __cplusplus
 }
 #endif