AudioFormat (Java 2 Platform SE v1.4.1_"07")

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JavaTM 2 Platform
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## 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

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JavaTM 2 Platform
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2002 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.