/*
* Copyright 1999-2004 Carnegie Mellon University.
* Portions Copyright 2002-2004 Sun Microsystems, Inc.
* Portions Copyright 2002-2004 Mitsubishi Electric Research Laboratories.
* All Rights Reserved. Use is subject to license terms.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
*
*/
package edu.cmu.sphinx.tools.audio;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioFormat.Encoding;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.UnsupportedAudioFileException;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class Utils {
/** Index = ulaw value, entry = signed 16 bit value. */
static final private short[] ulawTable = {
32760, 31608, 30584, 29560, 28536, 27512, 26488, 25464, 24440,
23416, 22392, 21368, 20344, 19320, 18296, 17272, 16248, 15736,
15224, 14712, 14200, 13688, 13176, 12664, 12152, 11640, 11128,
10616, 10104, 9592, 9080, 8568, 8056, 7800, 7544, 7288, 7032,
6776, 6520, 6264, 6008, 5752, 5496, 5240, 4984, 4728, 4472,
4216, 3960, 3832, 3704, 3576, 3448, 3320, 3192, 3064, 2936,
2808, 2680, 2552, 2424, 2296, 2168, 2040, 1912, 1848, 1784,
1720, 1656, 1592, 1528, 1464, 1400, 1336, 1272, 1208, 1144,
1080, 1016, 952, 888, 856, 824, 792, 760, 728, 696, 664, 632,
600, 568, 536, 504, 472, 440, 408, 376, 360, 344, 328, 312,
296, 280, 264, 248, 232, 216, 200, 184, 168, 152, 136, 120,
112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0,
-32760, -31608, -30584, -29560, -28536, -27512, -26488, -25464,
-24440, -23416, -22392, -21368, -20344, -19320, -18296, -17272,
-16248, -15736, -15224, -14712, -14200, -13688, -13176, -12664,
-12152, -11640, -11128, -10616, -10104, -9592, -9080, -8568,
-8056, -7800, -7544, -7288, -7032, -6776, -6520, -6264, -6008,
-5752, -5496, -5240, -4984, -4728, -4472, -4216, -3960, -3832,
-3704, -3576, -3448, -3320, -3192, -3064, -2936, -2808, -2680,
-2552, -2424, -2296, -2168, -2040, -1912, -1848, -1784, -1720,
-1656, -1592, -1528, -1464, -1400, -1336, -1272, -1208, -1144,
-1080, -1016, -952, -888, -856, -824, -792, -760, -728, -696,
-664, -632, -600, -568, -536, -504, -472, -440, -408, -376,
-360, -344, -328, -312, -296, -280, -264, -248, -232, -216,
-200, -184, -168, -152, -136, -120, -112, -104, -96, -88, -80,
-72, -64, -56, -48, -40, -32, -24, -16, -8, 0};
/** Uninstantiable class. */
private Utils() {
}
/** Converts a byte array to a signed short value. */
static public short toShort(byte[] bytes, boolean bigEndian) {
if (bytes.length == 1) {
return bytes[0];
} else if (bigEndian) {
return (short) ((bytes[0] << 8) | (0xff & bytes[1]));
} else {
return (short) ((bytes[1] << 8) | (0xff & bytes[0]));
}
}
/** Converts a byte array into an unsigned short. */
static public int toUnsignedShort(byte[] bytes, boolean bigEndian) {
if (bytes.length == 1) {
return 0xff & bytes[0];
} else if (bigEndian) {
return ((bytes[0] & 0xff) << 8) | (0xff & bytes[1]);
} else {
return ((bytes[1] & 0xff) << 8) | (0xff & bytes[0]);
}
}
/** Converts a short into a byte array. */
public static void toBytes(short sVal, byte[] bytes, boolean bigEndian) {
if (bigEndian) {
bytes[0] = (byte) (sVal >> 8);
bytes[1] = (byte) (sVal & 0xff);
} else {
bytes[0] = (byte) (sVal & 0xff);
bytes[1] = (byte) (sVal >> 8);
}
}
/**
* Convert the bytes starting at the given offset to a signed short based upon the AudioFormat. If the frame size
* is 1, then the value is doubled to make it match a frame size of 2.
*
* @param format the audio format
* @param byteArray the byte array
* @return a short
* @throws java.lang.ArrayIndexOutOfBoundsException
*
*/
public static short bytesToShort(AudioFormat format,
byte[] byteArray) {
short result = 0;
Encoding encoding = format.getEncoding();
int frameSize = format.getFrameSize();
if (encoding == Encoding.PCM_SIGNED) {
result = toShort(byteArray, format.isBigEndian());
if (frameSize == 1) {
result = (short) (result << 8);
}
} else if (encoding == Encoding.PCM_UNSIGNED) {
int tmp = toUnsignedShort(byteArray, format.isBigEndian());
if (frameSize == 1) {
tmp = tmp << 8;
}
result = (short) (tmp - (2 << 14));
} else if (encoding == Encoding.ULAW) {
result = ulawTable[byteArray[0] + 128];
} else {
System.out.println("Unknown encoding: " + encoding);
}
return result;
}
/**
* Turns the AudioInputStream into a 16bit, SIGNED_PCM, little endian audio stream that preserves the original sample
* rate of the AudioInputStream. NOTE: this assumes the frame size can be only 1 or 2 bytes. The AudioInputStream
* is left in a state of having all of its data being read.
*/
static public short[] toSignedPCM(AudioInputStream ais)
throws IOException {
AudioFormat aisFormat = ais.getFormat();
short[] shorts = new short[ais.available() / aisFormat.getFrameSize()];
byte[] frame = new byte[aisFormat.getFrameSize()];
int pos = 0;
while (ais.read(frame) != -1) {
shorts[pos++] = bytesToShort(aisFormat, frame);
}
return shorts;
}
/**
* Attempts to read an audio file using the Java Sound APIs. If this file isn't a typical audio file, then this
* returns a null. Otherwise, it converts the data into a 8kHz 16-bit signed PCM little endian clip.
*
* @param filename the file containing audio data
* @return the audio data or null if the audio cannot be parsed
*/
static public AudioData readAudioFile(String filename) throws IOException {
try {
BufferedInputStream stream = new BufferedInputStream(
new FileInputStream(filename));
AudioInputStream ais = AudioSystem.getAudioInputStream(stream);
AudioData audioData = new AudioData(ais);
stream.close();
return audioData;
} catch (UnsupportedAudioFileException e) {
return null;
}
}
/**
* Reads the given stream in as 8kHz 16-bit signed PCM little endian audio data and returns an audio clip.
*
* @param filename the file containing audio data
* @return the audio data or null if the audio cannot be parsed
*/
static public AudioData readRawFile(String filename)
throws IOException {
FileInputStream stream = new FileInputStream(filename);
AudioFormat format = new AudioFormat(8000.0f, // sample rate
16, // sample size
1, // channels (1 == mono)
true, // signed
false); // little endian
short[] audioData = RawReader.readAudioData(stream, format);
stream.close();
return new AudioData(audioData, 8000.0f);
}
/** Writes the given 8kHz 16-bit signed PCM audio clip to the given file as raw little endian data. */
static public void writeRawFile(AudioData audio, String filename)
throws IOException {
FileOutputStream outputStream = new FileOutputStream(filename);
AudioFormat format = new AudioFormat(
8000.0f, // sample rate
16, // sample size
1, // channels (1 == mono)
true, // signed
false); // little endian
RawWriter writer = new RawWriter(outputStream, format);
short[] samples = audio.getAudioData();
for (short sample : samples) {
writer.writeSample(sample);
}
outputStream.flush();
outputStream.close();
}
}