/*
* Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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*/
package com.sun.media.sound;
/**
* A simple look-ahead volume limiter with very fast attack and fast release.
* This filter is used for preventing clipping.
*
* @author Karl Helgason
*/
public class SoftLimiter implements SoftAudioProcessor {
float lastmax = 0;
float gain = 1;
float[] temp_bufferL;
float[] temp_bufferR;
boolean mix = false;
SoftAudioBuffer bufferL;
SoftAudioBuffer bufferR;
SoftAudioBuffer bufferLout;
SoftAudioBuffer bufferRout;
float controlrate;
public void init(float samplerate, float controlrate) {
this.controlrate = controlrate;
}
public void setInput(int pin, SoftAudioBuffer input) {
if (pin == 0)
bufferL = input;
if (pin == 1)
bufferR = input;
}
public void setOutput(int pin, SoftAudioBuffer output) {
if (pin == 0)
bufferLout = output;
if (pin == 1)
bufferRout = output;
}
public void setMixMode(boolean mix) {
this.mix = mix;
}
public void globalParameterControlChange(int[] slothpath, long param,
long value) {
}
double silentcounter = 0;
public void processAudio() {
if (this.bufferL.isSilent()
&& (this.bufferR == null || this.bufferR.isSilent())) {
silentcounter += 1 / controlrate;
if (silentcounter > 60) {
if (!mix) {
bufferLout.clear();
if(bufferRout != null) bufferRout.clear();
}
return;
}
} else
silentcounter = 0;
float[] bufferL = this.bufferL.array();
float[] bufferR = this.bufferR == null ? null : this.bufferR.array();
float[] bufferLout = this.bufferLout.array();
float[] bufferRout = this.bufferRout == null
? null : this.bufferRout.array();
if (temp_bufferL == null || temp_bufferL.length < bufferL.length)
temp_bufferL = new float[bufferL.length];
if (bufferR != null)
if (temp_bufferR == null || temp_bufferR.length < bufferR.length)
temp_bufferR = new float[bufferR.length];
float max = 0;
int len = bufferL.length;
if (bufferR == null) {
for (int i = 0; i < len; i++) {
if (bufferL[i] > max)
max = bufferL[i];
if (-bufferL[i] > max)
max = -bufferL[i];
}
} else {
for (int i = 0; i < len; i++) {
if (bufferL[i] > max)
max = bufferL[i];
if (bufferR[i] > max)
max = bufferR[i];
if (-bufferL[i] > max)
max = -bufferL[i];
if (-bufferR[i] > max)
max = -bufferR[i];
}
}
float lmax = lastmax;
lastmax = max;
if (lmax > max)
max = lmax;
float newgain = 1;
if (max > 0.99f)
newgain = 0.99f / max;
else
newgain = 1;
if (newgain > gain)
newgain = (newgain + gain * 9) / 10f;
float gaindelta = (newgain - gain) / len;
if (mix) {
if (bufferR == null) {
for (int i = 0; i < len; i++) {
gain += gaindelta;
float bL = bufferL[i];
float tL = temp_bufferL[i];
temp_bufferL[i] = bL;
bufferLout[i] += tL * gain;
}
} else {
for (int i = 0; i < len; i++) {
gain += gaindelta;
float bL = bufferL[i];
float bR = bufferR[i];
float tL = temp_bufferL[i];
float tR = temp_bufferR[i];
temp_bufferL[i] = bL;
temp_bufferR[i] = bR;
bufferLout[i] += tL * gain;
bufferRout[i] += tR * gain;
}
}
} else {
if (bufferR == null) {
for (int i = 0; i < len; i++) {
gain += gaindelta;
float bL = bufferL[i];
float tL = temp_bufferL[i];
temp_bufferL[i] = bL;
bufferLout[i] = tL * gain;
}
} else {
for (int i = 0; i < len; i++) {
gain += gaindelta;
float bL = bufferL[i];
float bR = bufferR[i];
float tL = temp_bufferL[i];
float tR = temp_bufferR[i];
temp_bufferL[i] = bL;
temp_bufferR[i] = bR;
bufferLout[i] = tL * gain;
bufferRout[i] = tR * gain;
}
}
}
gain = newgain;
}
public void processControlLogic() {
}
}