edu.cmu.sphinx.tools.audio

Class Utils

java.lang.Object

edu.cmu.sphinx.tools.audio.Utils

public class Utils
extends java.lang.Object

Method Summary

Modifier and Type	Method and Description
static short	bytesToShort(javax.sound.sampled.AudioFormat format, byte[] byteArray) Convert the bytes starting at the given offset to a signed short based upon the AudioFormat.
static AudioData	readAudioFile(java.lang.String filename) Attempts to read an audio file using the Java Sound APIs.
static AudioData	readRawFile(java.lang.String filename) Reads the given stream in as 8kHz 16-bit signed PCM little endian audio data and returns an audio clip.
static void	toBytes(short sVal, byte[] bytes, boolean bigEndian) Converts a short into a byte array.
static short	toShort(byte[] bytes, boolean bigEndian) Converts a byte array to a signed short value.
static short[]	toSignedPCM(javax.sound.sampled.AudioInputStream ais) Turns the AudioInputStream into a 16bit, SIGNED_PCM, little endian audio stream that preserves the original sample rate of the AudioInputStream.
static int	toUnsignedShort(byte[] bytes, boolean bigEndian) Converts a byte array into an unsigned short.
static void	writeRawFile(AudioData audio, java.lang.String filename) Writes the given 8kHz 16-bit signed PCM audio clip to the given file as raw little endian data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

toShort

public static short toShort(byte[] bytes,
                            boolean bigEndian)

Converts a byte array to a signed short value.

Parameters:

bytes - array to convert

bigEndian - is big endian

Returns:

converted value

toUnsignedShort

public static int toUnsignedShort(byte[] bytes,
                                  boolean bigEndian)

Converts a byte array into an unsigned short.

Parameters:

bytes - array to convert

bigEndian - is big endian

Returns:

converted value

toBytes

public static void toBytes(short sVal,
                           byte[] bytes,
                           boolean bigEndian)

Converts a short into a byte array.

Parameters:

sVal - source value

bytes - array to convert

bigEndian - is big endian

bytesToShort

public static short bytesToShort(javax.sound.sampled.AudioFormat format,
                                 byte[] byteArray)

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.

Parameters:

format - the audio format

byteArray - the byte array

Returns:

a short

toSignedPCM

public static short[] toSignedPCM(javax.sound.sampled.AudioInputStream ais)
                           throws java.io.IOException

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.

Parameters:

ais - stream to convert

Returns:

result array

Throws:

java.io.IOException - if error occurred

readAudioFile

public static AudioData readAudioFile(java.lang.String filename)
                               throws java.io.IOException

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.

Parameters:

filename - the file containing audio data

Returns:

the audio data or null if the audio cannot be parsed

Throws:

java.io.IOException - if error occured

readRawFile

public static AudioData readRawFile(java.lang.String filename)
                             throws java.io.IOException

Reads the given stream in as 8kHz 16-bit signed PCM little endian audio data and returns an audio clip.

Parameters:

filename - the file containing audio data

Returns:

the audio data or null if the audio cannot be parsed

Throws:

java.io.IOException - if exception occurred

writeRawFile

public static void writeRawFile(AudioData audio,
                                java.lang.String filename)
                         throws java.io.IOException

Writes the given 8kHz 16-bit signed PCM audio clip to the given file as raw little endian data.

Parameters:

audio - data

filename - filename to write to

Throws:

java.io.IOException - if IO went wrong