Class StdAudio

Object

StdAudio

public final class StdAudio
extends Object

Standard audio. This class provides a basic capability for creating, reading, and saving audio.

The audio format uses a sampling rate of 44,100 Hz, 16-bit, monaural.

For additional documentation, see Section 1.5 of Computer Science: An Interdisciplinary Approach by Robert Sedgewick and Kevin Wayne.

Author:

Robert Sedgewick, Kevin Wayne

Field Summary

Fields

Modifier and Type	Field and Description
static int	SAMPLE_RATE The sample rate: 44,100 Hz for CD quality audio.

Method Summary

Methods

Modifier and Type	Method and Description
static void	close() Closes standard audio.
static void	loop(String filename) Loops an audio file (in .wav, .mid, or .au format) in a background thread.
static void	main(String[] args) Test client - play an A major scale to standard audio.
static void	play(double sample) Writes one sample (between -1.0 and +1.0) to standard audio.
static void	play(double[] samples) Writes the array of samples (between -1.0 and +1.0) to standard audio.
static void	play(String filename) Plays an audio file (in .wav, .mid, or .au format) in a background thread.
static double[]	read(String filename) Reads audio samples from a file (in .wav or .au format) and returns them as a double array with values between -1.0 and +1.0.
static void	save(String filename, double[] samples) Saves the double array as an audio file (using .wav or .au format).

Methods inherited from class Object

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

Field Detail

SAMPLE_RATE

public static final int SAMPLE_RATE

The sample rate: 44,100 Hz for CD quality audio.

See Also:

Constant Field Values

Method Detail

close

public static void close()

Closes standard audio.

play

public static void play(double sample)

Writes one sample (between -1.0 and +1.0) to standard audio. If the sample is outside the range, it will be clipped.

Parameters:

sample - the sample to play

Throws:

IllegalArgumentException - if the sample is Double.NaN

play

public static void play(double[] samples)

Writes the array of samples (between -1.0 and +1.0) to standard audio. If a sample is outside the range, it will be clipped.

Parameters:

samples - the array of samples to play

Throws:

IllegalArgumentException - if any sample is Double.NaN

IllegalArgumentException - if samples is null

read

public static double[] read(String filename)

Reads audio samples from a file (in .wav or .au format) and returns them as a double array with values between -1.0 and +1.0. The audio file must be 16-bit with a sampling rate of 44,100. It can be mono or stereo.

Parameters:

filename - the name of the audio file

Returns:

the array of samples

save

public static void save(String filename,
        double[] samples)

Saves the double array as an audio file (using .wav or .au format).

Parameters:

filename - the name of the audio file

samples - the array of samples

Throws:

IllegalArgumentException - if unable to save filename

IllegalArgumentException - if samples is null

IllegalArgumentException - if filename is null

IllegalArgumentException - if filename extension is not .wav or .au

play

public static void play(String filename)

Plays an audio file (in .wav, .mid, or .au format) in a background thread.

Parameters:

filename - the name of the audio file

Throws:

IllegalArgumentException - if unable to play filename

IllegalArgumentException - if filename is null

loop

public static void loop(String filename)

Loops an audio file (in .wav, .mid, or .au format) in a background thread.

Parameters:

filename - the name of the audio file

Throws:

IllegalArgumentException - if filename is null

main

public static void main(String[] args)

Test client - play an A major scale to standard audio.

Parameters:

args - the command-line arguments