AudioFormat (Java 2 Platform SE v1.4.1)

javax.sound.sampled
Class AudioFormat
java.lang.Object
  |
  +--javax.sound.sampled.AudioFormat
public class AudioFormat
extends Object

AudioFormat is the class that specifies a particular arrangement of data in a sound stream. By examing the information stored in the audio format, you can discover how to interpret the bits in the binary sound data.
Every data line has an audio format associated with its data stream. The audio format of a source (playback) data line indicates what kind of data the data line expects to receive for output. For a target (capture) data line, the audio format specifies the kind of the data that can be read from the line. Sound files also have audio formats, of course. The AudioFileFormat class encapsulates an AudioFormat in addition to other, file-specific information. Similarly, an AudioInputStream has an AudioFormat.
The AudioFormat class accommodates a number of common sound-file encoding techniques, including pulse-code modulation (PCM), mu-law encoding, and a-law encoding. These encoding techniques are predefined, but service providers can create new encoding types. The encoding that a specific format uses is named by its encoding field.
In addition to the encoding, the audio format includes other properties that further specify the exact arrangement of the data. These include the number of channels, sample rate, sample size, byte order, frame rate, and frame size. Sounds may have different numbers of audio channels: one for mono, two for stereo. The sample rate measures how many "snapshots" (samples) of the sound pressure are taken per second, per channel. (If the sound is stereo rather than mono, two samples are actually measured at each instant of time: one for the left channel, and another for the right channel; however, the sample rate still measures the number per channel, so the rate is the same regardless of the number of channels. This is the standard use of the term.) The sample size indicates how many bits are used to store each snapshot; 8 and 16 are typical values. For 16-bit samples (or any other sample size larger than a byte), byte order is important; the bytes in each sample are arranged in either the "little-endian" or "big-endian" style. For encodings like PCM, a frame consists of the set of samples for all channels at a given point in time, and so the size of a frame (in bytes) is always equal to the size of a sample (in bytes) times the number of channels. However, with some other sorts of encodings a frame can contain a bundle of compressed data for a whole series of samples, as well as additional, non-sample data. For such encodings, the sample rate and sample size refer to the data after it is decoded into PCM, and so they are completely different from the frame rate and frame size.

Since:

1.3

See Also:
DataLine.getFormat(), AudioInputStream.getFormat(), AudioFileFormat, FormatConversionProvider

Nested Class Summary
static class AudioFormat.Encoding
    The Encoding class names the specific type of data representation used for an audio stream.

Field Summary
protected boolean bigEndian
    Indicates whether the audio data is stored in big-endian or little-endian order.
protected int channels
    The number of audio channels in this format (1 for mono, 2 for stereo).
protected AudioFormat.Encoding encoding
    The audio encoding technique used by this format.
protected float frameRate
    The number of frames played or recorded per second, for sounds that have this format.
protected int frameSize
    The number of bytes in each frame of a sound that has this format.
protected float sampleRate
    The number of samples played or recorded per second, for sounds that have this format.
protected int sampleSizeInBits
    The number of bits in each sample of a sound that has this format.

Constructor Summary
AudioFormat(AudioFormat.Encoding encoding, float sampleRate, int sampleSizeInBits, int channels, int frameSize, float frameRate, boolean bigEndian)
    Constructs an AudioFormat with the given parameters.
AudioFormat(float sampleRate, int sampleSizeInBits, int channels, boolean signed, boolean bigEndian)
    Constructs an AudioFormat with a linear PCM encoding and the given parameters.

Method Summary
int getChannels()
    Obtains the number of channels.
AudioFormat.Encoding getEncoding()
    Obtains the type of encoding for sounds in this format.
float getFrameRate()
    Obtains the frame rate in frames per second.
int getFrameSize()
    Obtains the frame size in bytes.
float getSampleRate()
    Obtains the sample rate.
int getSampleSizeInBits()
    Obtains the size of a sample.
boolean isBigEndian()
    Indicates whether the audio data is stored in big-endian or little-endian byte order.
boolean matches(AudioFormat format)
    Indicates whether this format matches the one specified.
String toString()
    Returns a string that describes the format, such as: "PCM SIGNED 22050 Hz 16 bit mono big-endian audio data".

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

encoding
protected AudioFormat.Encoding encoding
The audio encoding technique used by this format.

sampleRate
protected float sampleRate
The number of samples played or recorded per second, for sounds that have this format.

sampleSizeInBits
protected int sampleSizeInBits
The number of bits in each sample of a sound that has this format.

channels
protected int channels
The number of audio channels in this format (1 for mono, 2 for stereo).

frameSize
protected int frameSize
The number of bytes in each frame of a sound that has this format.

frameRate
protected float frameRate
The number of frames played or recorded per second, for sounds that have this format.

bigEndian
protected boolean bigEndian
Indicates whether the audio data is stored in big-endian or little-endian order.

Constructor Detail

AudioFormat
public AudioFormat(AudioFormat.Encoding encoding,
                   float sampleRate,
                   int sampleSizeInBits,
                   int channels,
                   int frameSize,
                   float frameRate,
                   boolean bigEndian)
Constructs an AudioFormat with the given parameters. The encoding specifies the convention used to represent the data. The other parameters are further explained in the class description.

Parameters:
encoding - the audio encoding technique
sampleRate - the number of samples per second
sampleSizeInBits - the number of bits in each sample
channels - the number of channels (1 for mono, 2 for stereo, and so on)
frameSize - the number of bytes in each frame
frameRate - the number of frames per second
bigEndian - indicates whether the data for a single sample is stored in big-endian byte order (false means little-endian)

AudioFormat
public AudioFormat(float sampleRate,
                   int sampleSizeInBits,
                   int channels,
                   boolean signed,
                   boolean bigEndian)
Constructs an AudioFormat with a linear PCM encoding and the given parameters. The frame size is set to the number of bytes required to contain one sample from each channel, and the frame rate is set to the sample rate.

Parameters:
sampleRate - the number of samples per second
sampleSizeInBits - the number of bits in each sample
channels - the number of channels (1 for mono, 2 for stereo, and so on)
signed - indicates whether the data is signed or unsigned
bigEndian - indicates whether the data for a single sample is stored in big-endian byte order (false means little-endian)

Method Detail

getEncoding
public AudioFormat.Encoding getEncoding()
Obtains the type of encoding for sounds in this format.

Returns:
the encoding type
See Also:
AudioFormat.Encoding.PCM_SIGNED, AudioFormat.Encoding.PCM_UNSIGNED, AudioFormat.Encoding.ULAW, AudioFormat.Encoding.ALAW

getSampleRate
public float getSampleRate()
Obtains the sample rate. For compressed formats, the return value is the sample rate of the uncompressed audio data. When this AudioFormat is used for queries (e.g. AudioSystem.isConversionSupported) or capabilities (e.g. DataLine.Info.getFormats), a sample rate of AudioSystem.NOT_SPECIFIED means that any sample rate is acceptable. AudioSystem.NOT_SPECIFIED is also returned when the sample rate is not defined for this audio format.

Returns:
the number of samples per second, or AudioSystem.NOT_SPECIFIED
See Also:
getFrameRate(), AudioSystem.NOT_SPECIFIED

getSampleSizeInBits
public int getSampleSizeInBits()
Obtains the size of a sample. For compressed formats, the return value is the sample size of the uncompressed audio data. When this AudioFormat is used for queries (e.g. AudioSystem.isConversionSupported) or capabilities (e.g. DataLine.Info.getFormats), a sample size of AudioSystem.NOT_SPECIFIED means that any sample size is acceptable. AudioSystem.NOT_SPECIFIED is also returned when the sample size is not defined for this audio format.

Returns:
the number of bits in each sample, or AudioSystem.NOT_SPECIFIED
See Also:
getFrameSize(), AudioSystem.NOT_SPECIFIED

getChannels
public int getChannels()
Obtains the number of channels. When this AudioFormat is used for queries (e.g. AudioSystem.isConversionSupported) or capabilities (e.g. DataLine.Info.getFormats), a return value of AudioSystem.NOT_SPECIFIED means that any (positive) number of channels is acceptable.

Returns:
The number of channels (1 for mono, 2 for stereo, etc.), or AudioSystem.NOT_SPECIFIED
See Also:
AudioSystem.NOT_SPECIFIED

getFrameSize
public int getFrameSize()
Obtains the frame size in bytes. When this AudioFormat is used for queries (e.g. AudioSystem.isConversionSupported) or capabilities (e.g. DataLine.Info.getFormats), a frame size of AudioSystem.NOT_SPECIFIED means that any frame size is acceptable. AudioSystem.NOT_SPECIFIED is also returned when the frame size is not defined for this audio format.

Returns:
the number of bytes per frame, or AudioSystem.NOT_SPECIFIED
See Also:
getSampleSizeInBits(), AudioSystem.NOT_SPECIFIED

getFrameRate
public float getFrameRate()
Obtains the frame rate in frames per second. When this AudioFormat is used for queries (e.g. AudioSystem.isConversionSupported) or capabilities (e.g. DataLine.Info.getFormats), a frame rate of AudioSystem.NOT_SPECIFIED means that any frame rate is acceptable. AudioSystem.NOT_SPECIFIED is also returned when the frame rate is not defined for this audio format.

Returns:
the number of frames per second, or AudioSystem.NOT_SPECIFIED
See Also:
getSampleRate(), AudioSystem.NOT_SPECIFIED

isBigEndian
public boolean isBigEndian()
Indicates whether the audio data is stored in big-endian or little-endian byte order. If the sample size is not more than one byte, the return value is irrelevant.

Returns:
true if the data is stored in big-endian byte order, false if little-endian

matches
public boolean matches(AudioFormat format)
Indicates whether this format matches the one specified. To match, two formats must have the same encoding, the same number of channels, and the same number of bits per sample and bytes per frame. The two formats must also have the same sample rate, unless the specified format has the sample rate value AudioSystem.NOT_SPECIFIED, which any sample rate will match. The frame rates must similarly be equal, unless the specified format has the frame rate value AudioSystem.NOT_SPECIFIED. The byte order (big-endian or little-endian) must match if the sample size is greater than one byte.

Parameters:
format - format to test for match
Returns:
true if this format matches the one specified, false otherwise.

toString
public String toString()
Returns a string that describes the format, such as: "PCM SIGNED 22050 Hz 16 bit mono big-endian audio data". The contents of the string may vary between implementations of Java Sound.

Overrides:
toString in class Object

Returns:
a string that describes the format parameters

Field Summary
protected boolean	bigEndian Indicates whether the audio data is stored in big-endian or little-endian order.
protected int	channels The number of audio channels in this format (1 for mono, 2 for stereo).
protected AudioFormat.Encoding	encoding The audio encoding technique used by this format.
protected float	frameRate The number of frames played or recorded per second, for sounds that have this format.
protected int	frameSize The number of bytes in each frame of a sound that has this format.
protected float	sampleRate The number of samples played or recorded per second, for sounds that have this format.
protected int	sampleSizeInBits The number of bits in each sample of a sound that has this format.

Method Summary
int	getChannels() Obtains the number of channels.
AudioFormat.Encoding	getEncoding() Obtains the type of encoding for sounds in this format.
float	getFrameRate() Obtains the frame rate in frames per second.
int	getFrameSize() Obtains the frame size in bytes.
float	getSampleRate() Obtains the sample rate.
int	getSampleSizeInBits() Obtains the size of a sample.
boolean	isBigEndian() Indicates whether the audio data is stored in big-endian or little-endian byte order.
boolean	matches(AudioFormat format) Indicates whether this format matches the one specified.
String	toString() Returns a string that describes the format, such as: "PCM SIGNED 22050 Hz 16 bit mono big-endian audio data".

javax.sound.sampled Class AudioFormat

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

encoding

sampleRate

sampleSizeInBits

channels

frameSize

frameRate

bigEndian

Constructor Detail

AudioFormat

AudioFormat

Method Detail

getEncoding

getSampleRate

getSampleSizeInBits

getChannels

getFrameSize

getFrameRate

isBigEndian

matches

toString

javax.sound.sampled
Class AudioFormat