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/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/audio_processing/agc/utility.h"
#include <math.h>
namespace webrtc {
static const double kLog10 = 2.30258509299;
static const double kLinear2DbScale = 20.0 / kLog10;
static const double kLinear2LoudnessScale = 13.4 / kLog10;
double Loudness2Db(double loudness) {
return loudness * kLinear2DbScale / kLinear2LoudnessScale;
}
double Linear2Loudness(double rms) {
if (rms == 0)
return -15;
return kLinear2LoudnessScale * log(rms);
}
double Db2Loudness(double db) {
return db * kLinear2LoudnessScale / kLinear2DbScale;
}
double Dbfs2Loudness(double dbfs) {
return Db2Loudness(90 + dbfs);
}
} // namespace webrtc