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package javax.sound.sampled;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
/**
* {@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.
* <p>
* Sound files also have audio formats, of course. The {@link AudioFileFormat}
* class encapsulates an {@code AudioFormat} in addition to other, file-specific
* information. Similarly, an {@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 {@code 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 class="striped">
* <caption>Audio Format Properties</caption>
* <thead>
* <tr>
* <th scope="col">Property key
* <th scope="col">Value type
* <th scope="col">Description
* </thead>
* <tbody>
* <tr>
* <th scope="row">"bitrate"
* <td>{@link java.lang.Integer Integer}
* <td>average bit rate in bits per second
* <tr>
* <th scope="row">"vbr"
* <td>{@link java.lang.Boolean Boolean}
* <td>{@code true}, if the file is encoded in variable bit rate (VBR)
* <tr>
* <th scope="row">"quality"
* <td>{@link java.lang.Integer Integer}
* <td>encoding/conversion quality, 1..100
* </tbody>
* </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 {
/**
* 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<>(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 {@code 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
* {@code 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 {@code 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 {@code 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
* {@code 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
*/
@SuppressWarnings("unchecked") // Cast of result of clone.
public Map<String,Object> properties() {
Map<String,Object> ret;
if (properties == null) {
ret = new HashMap<>(0);
} else {
ret = (Map<String,Object>) (properties.clone());
}
return 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
*/
@Override
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 {@code PCM_SIGNED} or
* {@code PCM_UNSIGNED}. Service providers can create new encodings, such as
* compressed audio formats, and make these available through the
* {@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.
*
* @author Kara Kytle
* @see AudioFormat
* @see javax.sound.sampled.spi.FormatConversionProvider
* @since 1.3
*/
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