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/*
* Copyright (C) 2016 "IoT.bzh"
* Author Fulup Ar Foll <fulup@iot.bzh>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* references:
* alsa-util/amixer.c + alsa-lib/simple.c
*/
#define _GNU_SOURCE // needed for vasprintf
#include <math.h>
#include "hal-interface.h"
typedef enum {
DB_NORMALIZE_LINEAR,
DB_NORMALIZE_MATH,
} enumRandeModeDB_T;
// Return Value express from 0-100%
STATIC int dbNormalizeVal (enumRandeModeDB_T normaliseMode, const alsaHalDBscaleT *dbscale, int value) {
double normalized, min_norm;
// To get real DB from TLV DB values should be divided by 100
switch (normaliseMode) {
case DB_NORMALIZE_LINEAR:
normalized = ((double)(value-dbscale->min)/(double)(dbscale->max-dbscale->min))*100;
break;
case DB_NORMALIZE_MATH:
normalized = exp10((double)(value - dbscale->max) / 6000.0);
if (dbscale->min != SND_CTL_TLV_DB_GAIN_MUTE) {
min_norm = exp10((double)(dbscale->min - dbscale->max) / 6000.0);
normalized = (normalized - min_norm) / (1 - min_norm);
}
break;
default:
normalized=0;
}
return (int)round(normalized*100);
}
// HAL normalise volume values to 0-100%
PUBLIC struct json_object *GetNormaliseVolume(const alsaHalCtlMapT *halCtls, struct json_object *valuesJ) {
int useNormalizeDB;
// If not valid db_scale let's use raw_scale
if (!halCtls->dbscale || (halCtls->dbscale->min >= halCtls->dbscale->max)) {
// dbscale is invalid let's try raw range
if (halCtls->minval >= halCtls->maxval) goto ExitOnError;
// Use Raw Scale Model
useNormalizeDB= 0;
} else { // db_scale looks OK let's use it
if ((halCtls->dbscale->max - halCtls->dbscale->min) <= MAX_LINEAR_DB_SCALE * 100) useNormalizeDB= DB_NORMALIZE_LINEAR;
else useNormalizeDB = DB_NORMALIZE_MATH;
}
// loop on values to normalise
int length = json_object_array_length(valuesJ);
json_object *normalisedJ= json_object_new_array();
for (int idx=0; idx <length; idx++) {
json_object *valueJ = json_object_array_get_idx (valuesJ, idx);
int value = json_object_get_int(valueJ);
// If Integer scale to 0/100
if (halCtls->type == SND_CTL_ELEM_TYPE_INTEGER) {
if (useNormalizeDB) value = dbNormalizeVal (useNormalizeDB, halCtls->dbscale, value);
else value = 100* (value - halCtls->minval) / (halCtls->maxval - halCtls->minval);
}
json_object_array_add(normalisedJ, json_object_new_int(value));
}
return (normalisedJ);
ExitOnError:
return NULL;
}
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