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Java example source code file (AudioFormat.java)
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The AudioFormat.java Java example source code
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.sound.sampled;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* <code>AudioFormat is the class that specifies a particular arrangement of data in a sound stream.
* By examining the information stored in the audio format, you can discover how to interpret the bits in the
* binary sound data.
* <p>
* 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 <code>{@link AudioFileFormat}
* class encapsulates an <code>AudioFormat in addition to other,
* file-specific information. Similarly, an <code>{@link AudioInputStream} has an
* <code>AudioFormat.
* <p>
* The <code>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 <code>encoding field.
*<p>
* 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.
*
* <p>An AudioFormat object can include a set of
* properties. A property is a pair of key and value: the key
* is of type <code>String, the associated property
* value is an arbitrary object. Properties specify
* additional format specifications, like the bit rate for
* compressed formats. Properties are mainly used as a means
* to transport additional information of the audio format
* to and from the service providers. Therefore, properties
* are ignored in the {@link #matches(AudioFormat)} method.
* However, methods which rely on the installed service
* providers, like {@link AudioSystem#isConversionSupported
* (AudioFormat, AudioFormat) isConversionSupported} may consider
* properties, depending on the respective service provider
* implementation.
*
* <p>The following table lists some common properties which
* service providers should use, if applicable:
*
* <table border=0>
* <caption>Audio Format Properties
* <tr>
* <th>Property key
* <th>Value type
* <th>Description
* </tr>
* <tr>
* <td>"bitrate" |
* <td>{@link java.lang.Integer Integer}
* <td>average bit rate in bits per second
* </tr>
* <tr>
* <td>"vbr"
* <td>{@link java.lang.Boolean Boolean}
* <td>true, if the file is encoded in variable bit
* rate (VBR)</td>
* </tr>
* <tr>
* <td>"quality"
* <td>{@link java.lang.Integer Integer}
* <td>encoding/conversion quality, 1..100
* </tr>
* </table>
*
* <p>Vendors of service providers (plugins) are encouraged
* to seek information about other already established
* properties in third party plugins, and follow the same
* conventions.
*
* @author Kara Kytle
* @author Florian Bomers
* @see DataLine#getFormat
* @see AudioInputStream#getFormat
* @see AudioFileFormat
* @see javax.sound.sampled.spi.FormatConversionProvider
* @since 1.3
*/
public class AudioFormat {
// INSTANCE VARIABLES
/**
* The audio encoding technique used by this format.
*/
protected Encoding encoding;
/**
* The number of samples played or recorded per second, for sounds that have this format.
*/
protected float sampleRate;
/**
* The number of bits in each sample of a sound that has this format.
*/
protected int sampleSizeInBits;
/**
* The number of audio channels in this format (1 for mono, 2 for stereo).
*/
protected int channels;
/**
* The number of bytes in each frame of a sound that has this format.
*/
protected int frameSize;
/**
* The number of frames played or recorded per second, for sounds that have this format.
*/
protected float frameRate;
/**
* Indicates whether the audio data is stored in big-endian or little-endian order.
*/
protected boolean bigEndian;
/** The set of properties */
private HashMap<String, Object> properties;
/**
* Constructs an <code>AudioFormat with the given parameters.
* The encoding specifies the convention used to represent the data.
* The other parameters are further explained in the {@link AudioFormat
* class description}.
* @param encoding the audio encoding technique
* @param sampleRate the number of samples per second
* @param sampleSizeInBits the number of bits in each sample
* @param channels the number of channels (1 for mono, 2 for stereo, and so on)
* @param frameSize the number of bytes in each frame
* @param frameRate the number of frames per second
* @param bigEndian indicates whether the data for a single sample
* is stored in big-endian byte order (<code>false
* means little-endian)
*/
public AudioFormat(Encoding encoding, float sampleRate, int sampleSizeInBits,
int channels, int frameSize, float frameRate, boolean bigEndian) {
this.encoding = encoding;
this.sampleRate = sampleRate;
this.sampleSizeInBits = sampleSizeInBits;
this.channels = channels;
this.frameSize = frameSize;
this.frameRate = frameRate;
this.bigEndian = bigEndian;
this.properties = null;
}
/**
* Constructs an <code>AudioFormat with the given parameters.
* The encoding specifies the convention used to represent the data.
* The other parameters are further explained in the {@link AudioFormat
* class description}.
* @param encoding the audio encoding technique
* @param sampleRate the number of samples per second
* @param sampleSizeInBits the number of bits in each sample
* @param channels the number of channels (1 for mono, 2 for
* stereo, and so on)
* @param frameSize the number of bytes in each frame
* @param frameRate the number of frames per second
* @param bigEndian indicates whether the data for a single sample
* is stored in big-endian byte order
* (<code>false means little-endian)
* @param properties a <code>Map<String,Object> object
* containing format properties
*
* @since 1.5
*/
public AudioFormat(Encoding encoding, float sampleRate,
int sampleSizeInBits, int channels,
int frameSize, float frameRate,
boolean bigEndian, Map<String, Object> properties) {
this(encoding, sampleRate, sampleSizeInBits, channels,
frameSize, frameRate, bigEndian);
this.properties = new HashMap<String, Object>(properties);
}
/**
* Constructs an <code>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.
*
* @param sampleRate the number of samples per second
* @param sampleSizeInBits the number of bits in each sample
* @param channels the number of channels (1 for mono, 2 for stereo, and so on)
* @param signed indicates whether the data is signed or unsigned
* @param bigEndian indicates whether the data for a single sample
* is stored in big-endian byte order (<code>false
* means little-endian)
*/
public AudioFormat(float sampleRate, int sampleSizeInBits,
int channels, boolean signed, boolean bigEndian) {
this((signed == true ? Encoding.PCM_SIGNED : Encoding.PCM_UNSIGNED),
sampleRate,
sampleSizeInBits,
channels,
(channels == AudioSystem.NOT_SPECIFIED || sampleSizeInBits == AudioSystem.NOT_SPECIFIED)?
AudioSystem.NOT_SPECIFIED:
((sampleSizeInBits + 7) / 8) * channels,
sampleRate,
bigEndian);
}
/**
* Obtains the type of encoding for sounds in this format.
*
* @return the encoding type
* @see Encoding#PCM_SIGNED
* @see Encoding#PCM_UNSIGNED
* @see Encoding#ULAW
* @see Encoding#ALAW
*/
public Encoding getEncoding() {
return encoding;
}
/**
* 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. {@link
* AudioSystem#isConversionSupported(AudioFormat, AudioFormat)
* AudioSystem.isConversionSupported}) or capabilities (e.g. {@link
* DataLine.Info#getFormats() DataLine.Info.getFormats}), a sample rate of
* <code>AudioSystem.NOT_SPECIFIED means that any sample rate is
* acceptable. <code>AudioSystem.NOT_SPECIFIED is also returned when
* the sample rate is not defined for this audio format.
* @return the number of samples per second,
* or <code>AudioSystem.NOT_SPECIFIED
*
* @see #getFrameRate()
* @see AudioSystem#NOT_SPECIFIED
*/
public float getSampleRate() {
return sampleRate;
}
/**
* 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. {@link
* AudioSystem#isConversionSupported(AudioFormat, AudioFormat)
* AudioSystem.isConversionSupported}) or capabilities (e.g. {@link
* DataLine.Info#getFormats() DataLine.Info.getFormats}), a sample size of
* <code>AudioSystem.NOT_SPECIFIED means that any sample size is
* acceptable. <code>AudioSystem.NOT_SPECIFIED is also returned when
* the sample size is not defined for this audio format.
* @return the number of bits in each sample,
* or <code>AudioSystem.NOT_SPECIFIED
*
* @see #getFrameSize()
* @see AudioSystem#NOT_SPECIFIED
*/
public int getSampleSizeInBits() {
return sampleSizeInBits;
}
/**
* Obtains the number of channels.
* When this AudioFormat is used for queries (e.g. {@link
* AudioSystem#isConversionSupported(AudioFormat, AudioFormat)
* AudioSystem.isConversionSupported}) or capabilities (e.g. {@link
* DataLine.Info#getFormats() DataLine.Info.getFormats}), a return value of
* <code>AudioSystem.NOT_SPECIFIED means that any (positive) number of channels is
* acceptable.
* @return The number of channels (1 for mono, 2 for stereo, etc.),
* or <code>AudioSystem.NOT_SPECIFIED
*
* @see AudioSystem#NOT_SPECIFIED
*/
public int getChannels() {
return channels;
}
/**
* Obtains the frame size in bytes.
* When this AudioFormat is used for queries (e.g. {@link
* AudioSystem#isConversionSupported(AudioFormat, AudioFormat)
* AudioSystem.isConversionSupported}) or capabilities (e.g. {@link
* DataLine.Info#getFormats() DataLine.Info.getFormats}), a frame size of
* <code>AudioSystem.NOT_SPECIFIED means that any frame size is
* acceptable. <code>AudioSystem.NOT_SPECIFIED is also returned when
* the frame size is not defined for this audio format.
* @return the number of bytes per frame,
* or <code>AudioSystem.NOT_SPECIFIED
*
* @see #getSampleSizeInBits()
* @see AudioSystem#NOT_SPECIFIED
*/
public int getFrameSize() {
return frameSize;
}
/**
* Obtains the frame rate in frames per second.
* When this AudioFormat is used for queries (e.g. {@link
* AudioSystem#isConversionSupported(AudioFormat, AudioFormat)
* AudioSystem.isConversionSupported}) or capabilities (e.g. {@link
* DataLine.Info#getFormats() DataLine.Info.getFormats}), a frame rate of
* <code>AudioSystem.NOT_SPECIFIED means that any frame rate is
* acceptable. <code>AudioSystem.NOT_SPECIFIED is also returned when
* the frame rate is not defined for this audio format.
* @return the number of frames per second,
* or <code>AudioSystem.NOT_SPECIFIED
*
* @see #getSampleRate()
* @see AudioSystem#NOT_SPECIFIED
*/
public float getFrameRate() {
return frameRate;
}
/**
* 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.
* @return <code>true if the data is stored in big-endian byte order,
* <code>false if little-endian
*/
public boolean isBigEndian() {
return bigEndian;
}
/**
* Obtain an unmodifiable map of properties.
* The concept of properties is further explained in
* the {@link AudioFileFormat class description}.
*
* @return a <code>Map<String,Object> object containing
* all properties. If no properties are recognized, an empty map is
* returned.
*
* @see #getProperty(String)
* @since 1.5
*/
public Map<String,Object> properties() {
Map<String,Object> ret;
if (properties == null) {
ret = new HashMap<String,Object>(0);
} else {
ret = (Map<String,Object>) (properties.clone());
}
return (Map<String,Object>) Collections.unmodifiableMap(ret);
}
/**
* Obtain the property value specified by the key.
* The concept of properties is further explained in
* the {@link AudioFileFormat class description}.
*
* <p>If the specified property is not defined for a
* particular file format, this method returns
* <code>null.
*
* @param key the key of the desired property
* @return the value of the property with the specified key,
* or <code>null if the property does not exist.
*
* @see #properties()
* @since 1.5
*/
public Object getProperty(String key) {
if (properties == null) {
return null;
}
return properties.get(key);
}
/**
* Indicates whether this format matches the one specified.
* To match, two formats must have the same encoding,
* and consistent values of the number of channels, sample rate, sample size,
* frame rate, and frame size.
* The values of the property are consistent if they are equal
* or the specified format has the property value
* {@code AudioSystem.NOT_SPECIFIED}.
* The byte order (big-endian or little-endian) must be the same
* if the sample size is greater than one byte.
*
* @param format format to test for match
* @return {@code true} if this format matches the one specified,
* {@code false} otherwise.
*/
public boolean matches(AudioFormat format) {
if (format.getEncoding().equals(getEncoding())
&& (format.getChannels() == AudioSystem.NOT_SPECIFIED
|| format.getChannels() == getChannels())
&& (format.getSampleRate() == (float)AudioSystem.NOT_SPECIFIED
|| format.getSampleRate() == getSampleRate())
&& (format.getSampleSizeInBits() == AudioSystem.NOT_SPECIFIED
|| format.getSampleSizeInBits() == getSampleSizeInBits())
&& (format.getFrameRate() == (float)AudioSystem.NOT_SPECIFIED
|| format.getFrameRate() == getFrameRate())
&& (format.getFrameSize() == AudioSystem.NOT_SPECIFIED
|| format.getFrameSize() == getFrameSize())
&& (getSampleSizeInBits() <= 8
|| format.isBigEndian() == isBigEndian())) {
return true;
}
return false;
}
/**
* Returns a string that describes the format, such as:
* "PCM SIGNED 22050 Hz 16 bit mono big-endian". The contents of the string
* may vary between implementations of Java Sound.
*
* @return a string that describes the format parameters
*/
public String toString() {
String sEncoding = "";
if (getEncoding() != null) {
sEncoding = getEncoding().toString() + " ";
}
String sSampleRate;
if (getSampleRate() == (float) AudioSystem.NOT_SPECIFIED) {
sSampleRate = "unknown sample rate, ";
} else {
sSampleRate = "" + getSampleRate() + " Hz, ";
}
String sSampleSizeInBits;
if (getSampleSizeInBits() == (float) AudioSystem.NOT_SPECIFIED) {
sSampleSizeInBits = "unknown bits per sample, ";
} else {
sSampleSizeInBits = "" + getSampleSizeInBits() + " bit, ";
}
String sChannels;
if (getChannels() == 1) {
sChannels = "mono, ";
} else
if (getChannels() == 2) {
sChannels = "stereo, ";
} else {
if (getChannels() == AudioSystem.NOT_SPECIFIED) {
sChannels = " unknown number of channels, ";
} else {
sChannels = ""+getChannels()+" channels, ";
}
}
String sFrameSize;
if (getFrameSize() == (float) AudioSystem.NOT_SPECIFIED) {
sFrameSize = "unknown frame size, ";
} else {
sFrameSize = "" + getFrameSize()+ " bytes/frame, ";
}
String sFrameRate = "";
if (Math.abs(getSampleRate() - getFrameRate()) > 0.00001) {
if (getFrameRate() == (float) AudioSystem.NOT_SPECIFIED) {
sFrameRate = "unknown frame rate, ";
} else {
sFrameRate = getFrameRate() + " frames/second, ";
}
}
String sEndian = "";
if ((getEncoding().equals(Encoding.PCM_SIGNED)
|| getEncoding().equals(Encoding.PCM_UNSIGNED))
&& ((getSampleSizeInBits() > 8)
|| (getSampleSizeInBits() == AudioSystem.NOT_SPECIFIED))) {
if (isBigEndian()) {
sEndian = "big-endian";
} else {
sEndian = "little-endian";
}
}
return sEncoding
+ sSampleRate
+ sSampleSizeInBits
+ sChannels
+ sFrameSize
+ sFrameRate
+ sEndian;
}
/**
* The <code>Encoding class names the specific type of data representation
* used for an audio stream. The encoding includes aspects of the
* sound format other than the number of channels, sample rate, sample size,
* frame rate, frame size, and byte order.
* <p>
* One ubiquitous type of audio encoding is pulse-code modulation (PCM),
* which is simply a linear (proportional) representation of the sound
* waveform. With PCM, the number stored in each sample is proportional
* to the instantaneous amplitude of the sound pressure at that point in
* time. The numbers may be signed or unsigned integers or floats.
* Besides PCM, other encodings include mu-law and a-law, which are nonlinear
* mappings of the sound amplitude that are often used for recording speech.
* <p>
* You can use a predefined encoding by referring to one of the static
* objects created by this class, such as PCM_SIGNED or
* PCM_UNSIGNED. Service providers can create new encodings, such as
* compressed audio formats, and make
* these available through the <code>{@link AudioSystem} class.
* <p>
* The <code>Encoding class is static, so that all
* <code>AudioFormat objects that have the same encoding will refer
* to the same object (rather than different instances of the same class).
* This allows matches to be made by checking that two format's encodings
* are equal.
*
* @see AudioFormat
* @see javax.sound.sampled.spi.FormatConversionProvider
*
* @author Kara Kytle
* @since 1.3
*/
public static class Encoding {
// ENCODING DEFINES
/**
* Specifies signed, linear PCM data.
*/
public static final Encoding PCM_SIGNED = new Encoding("PCM_SIGNED");
/**
* Specifies unsigned, linear PCM data.
*/
public static final Encoding PCM_UNSIGNED = new Encoding("PCM_UNSIGNED");
/**
* Specifies floating-point PCM data.
*
* @since 1.7
*/
public static final Encoding PCM_FLOAT = new Encoding("PCM_FLOAT");
/**
* Specifies u-law encoded data.
*/
public static final Encoding ULAW = new Encoding("ULAW");
/**
* Specifies a-law encoded data.
*/
public static final Encoding ALAW = new Encoding("ALAW");
// INSTANCE VARIABLES
/**
* Encoding name.
*/
private String name;
// CONSTRUCTOR
/**
* Constructs a new encoding.
* @param name the name of the new type of encoding
*/
public Encoding(String name) {
this.name = name;
}
// METHODS
/**
* Finalizes the equals method
*/
public final boolean equals(Object obj) {
if (toString() == null) {
return (obj != null) && (obj.toString() == null);
}
if (obj instanceof Encoding) {
return toString().equals(obj.toString());
}
return false;
}
/**
* Finalizes the hashCode method
*/
public final int hashCode() {
if (toString() == null) {
return 0;
}
return toString().hashCode();
}
/**
* Provides the <code>String representation of the encoding. This String is
* the same name that was passed to the constructor. For the predefined encodings, the name
* is similar to the encoding's variable (field) name. For example, <code>PCM_SIGNED.toString() returns
* the name "pcm_signed".
*
* @return the encoding name
*/
public final String toString() {
return name;
}
} // class Encoding
}
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