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package org.glassfish.jersey.examples.tonegen;
import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.LineUnavailableException;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
/**
* Generate DTMF tone waves and create a wave file.
*
* @author Adam Lindenthal (adam.lindenthal at oracle.com)
*/
public class ToneGenerator {
private static final float SAMPLE_RATE = 44100;
private static final int MAX_AMPLITUDE = 60;
/**
* Create a temporary file containing a DTMF tone in a .wav format.
*
* @param toneSequence {@link String} representing a desired DTMF sequence. Valid characters are digits (0-9),
* the hash sign (#) and star (*). Invalid characters are ignored.
* @param toneDuration duration of a single generated DTMF tone (represented by one character in toneSequence) in
* milliseconds
* @param silenceDuration duration of silence between two generated tones in milliseconds
* @return name of the generated temporary file on the server-side
* @throws LineUnavailableException
* @throws IOException
*/
public static String generate(String toneSequence, int toneDuration, int silenceDuration) throws LineUnavailableException,
IOException {
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
for (char toneValue : toneSequence.toCharArray()) {
DTMFTone tone = DTMFTone.forValue(toneValue);
if (tone == null) {
continue;
}
int loFreq = tone.getLoFreq();
int hiFreq = tone.getHiFreq();
byte[] bufLo = generateWaveForm(loFreq, MAX_AMPLITUDE, toneDuration);
byte[] bufHi = generateWaveForm(hiFreq, MAX_AMPLITUDE, toneDuration);
for (int i = 0; i < bufLo.length; i++) {
bufLo[i] = Integer.valueOf(bufLo[i] + bufHi[i]).byteValue();
}
outStream.write(bufLo);
outStream.write(generateSilence(silenceDuration));
}
outStream.flush();
byte[] output = outStream.toByteArray();
InputStream b_in = new ByteArrayInputStream(output);
return writeWav(b_in, output.length);
}
/**
* Generate the actual sinus wave of one simple tone.
*
* @param frequency frequency in Herz [Hz]
* @param volume maximum amplitude (note, that clipping/overflow may occur during mixing, if amplitude is too high)
* @param duration duration of the tone in milliseconds
* @return byte array representing the tone waveform
*/
private static byte[] generateWaveForm(int frequency, int volume, int duration) {
byte[] buffer = new byte[Float.valueOf(duration * (SAMPLE_RATE / 1000) + 1).intValue()];
for (int i = 0; i < duration * SAMPLE_RATE / 1000; i++) {
double alpha = i / (SAMPLE_RATE / frequency) * 2.0 * Math.PI;
buffer[i] = (byte) (Math.sin(alpha) * volume);
}
return buffer;
}
/**
* Generates a "waveform" for silence.
*
* @param duration duration of the silence
* @return byte array representing silence "waveform"
*/
private static byte[] generateSilence(int duration) {
byte buffer[] = new byte[Float.valueOf(duration * (SAMPLE_RATE / 1000) + 1).intValue()];
// all the bytes are initialized with zeros
return buffer;
}
/**
* Writes the temporary file with the generated audio.
*
* @param inputStream input stream with the waveform
* @param length length of the waveform
* @return name of the generated temporary file
* @throws IOException
*/
private static String writeWav(InputStream inputStream, int length) throws IOException {
AudioFormat format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED, SAMPLE_RATE, 8, 1, 1, SAMPLE_RATE, false);
File file = File.createTempFile("wav", ".");
AudioSystem.write(new AudioInputStream(inputStream, format, length), AudioFileFormat.Type.WAVE, file);
return file.getAbsolutePath();
}
}