org.jaudiotagger.audio.mp3
Class MPEGFrameHeader

java.lang.Object
  org.jaudiotagger.audio.mp3.MPEGFrameHeader

public class MPEGFrameHeader
extends java.lang.Object

Represents a MPEGFrameHeader, an MP3 is made up of a number of frames each frame starts with a four byte frame header.

Field Summary

private java.lang.Integer	bitRate Bitrate of this frame
private static java.util.Map<java.lang.Integer,java.lang.Integer>	bitrateMap Bit Rates, the setBitrate varies for different Version and Layer
private static int	BYTE_1 Constants for MP3 Frame header, each frame has a basic header of 4 bytes
private static int	BYTE_2
private static int	BYTE_3
private static int	BYTE_4
private int	channelMode Channel Mode of this Frame (see constants)
private java.lang.String	channelModeAsString Channel Mode of this Frame As English String
private int	emphasis Emphasis of this frame
static int	EMPHASIS_5015MS
static int	EMPHASIS_CCITT
static int	EMPHASIS_NONE
static int	EMPHASIS_RESERVED
private java.lang.String	emphasisAsString Emphasis mode string
private static java.util.Map<java.lang.Integer,java.lang.String>	emphasisMap Constants for Emphasis
private static byte[]	header
static int	HEADER_SIZE
private boolean	isCopyrighted Flag indicating if this frame contains copyrighted material
private boolean	isOriginal Flag indicating if this frame contains original material
private boolean	isPadding Flag indicating if this frame has padding byte
private boolean	isPrivate Flag indicating if this frame is private
private boolean	isProtected Flag indicating if this frame is protected
private int	layer Contains the mpeg layer of this frame (see constants)
static int	LAYER_I
private static int	LAYER_I_FRAME_SIZE_COEFFICIENT
static int	LAYER_I_SLOT_SIZE Slot Size is dependent on Layer
static int	LAYER_II
private static int	LAYER_II_FRAME_SIZE_COEFFICIENT
static int	LAYER_II_SLOT_SIZE
static int	LAYER_III
private static int	LAYER_III_FRAME_SIZE_COEFFICIENT
static int	LAYER_III_SLOT_SIZE
private java.lang.String	layerAsString
private static int	MASK_MP3_BITRATE The setBitrate of this MP3
private static int	MASK_MP3_COPY MP3 Frame Header bit mask
private static int	MASK_MP3_EMPHASIS MP3 Frame Header bit mask
private static int	MASK_MP3_FREQUENCY The sampling/frequency rate
private static int	MASK_MP3_HOME MP3 Frame Header bit mask
private static int	MASK_MP3_ID MP3 Frame Header bit mask
private static int	MASK_MP3_LAYER MP3 Layer, for MP3s the Layer is 3
private static int	MASK_MP3_MODE Channel Mode, Stero/Mono/Dual Channel
private static int	MASK_MP3_MODE_EXTENSION MP3 Frame Header bit mask
private static int	MASK_MP3_PADDING An extra padding bit is sometimes used to make sure frames are exactly the right length
private static int	MASK_MP3_PRIVACY Private bit set, for application specific
private static int	MASK_MP3_PROTECTION Does it include a CRC Checksum at end of header, this can be used to check the header.
private static int	MASK_MP3_VERSION MP3 version, confusingly for MP3s the version is 1.
static int	MODE_DUAL_CHANNEL
private static int	MODE_EXTENSION_NONE
private static int	MODE_EXTENSION_OFF_OFF
private static int	MODE_EXTENSION_OFF_ON
private static int	MODE_EXTENSION_ON_OFF
private static int	MODE_EXTENSION_ON_ON
private static int	MODE_EXTENSION_ONE
private static int	MODE_EXTENSION_THREE
private static int	MODE_EXTENSION_TWO
static int	MODE_JOINT_STEREO
static int	MODE_MONO
static int	MODE_STEREO
private java.lang.String	modeExtension Mode Extension
private static java.util.Map<java.lang.Integer,java.lang.String>	modeExtensionLayerIIIMap
private static java.util.Map<java.lang.Integer,java.lang.String>	modeExtensionMap
protected static java.util.Map<java.lang.Integer,java.lang.String>	modeMap Constants for Channel mode
private byte[]	mpegBytes
static java.util.Map<java.lang.Integer,java.lang.String>	mpegLayerMap Constants for MPEG Layer
static java.util.Map<java.lang.Integer,java.lang.String>	mpegVersionMap Constants for MPEG Version
private static java.util.Map<java.lang.Integer,java.util.Map<java.lang.Integer,java.lang.Integer>>	samplesPerFrameMap
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplesPerFrameV1Map
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplesPerFrameV25Map
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplesPerFrameV2Map
private java.lang.Integer	samplingRate
private static java.util.Map<java.lang.Integer,java.util.Map<java.lang.Integer,java.lang.Integer>>	samplingRateMap Sampling Rate in Hz
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplingV1Map
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplingV25Map
private static java.util.Map<java.lang.Integer,java.lang.Integer>	samplingV2Map
private static int	SCALE_BY_THOUSAND
static int	SYNC_BYTE1
static int	SYNC_BYTE2
static int	SYNC_SIZE Sync Value to identify the start of an MPEGFrame
private int	version The version of this MPEG frame (see the constants)
static int	VERSION_1
static int	VERSION_2
static int	VERSION_2_5
private java.lang.String	versionAsString

Constructor Summary

private	MPEGFrameHeader() Hide Constructor
private	MPEGFrameHeader(byte[] b) Try and create a new MPEG frame with the given byte array and decodes its contents If decoding header causes a problem it is not a valid header

Method Summary

java.lang.Integer	getBitRate()
int	getChannelMode()
java.lang.String	getChannelModeAsString()
int	getEmphasis()
java.lang.String	getEmphasisAsString()
int	getFrameLength()
int	getLayer() Gets the layerVersion attribute of the MPEGFrame object
java.lang.String	getLayerAsString()
java.lang.String	getModeExtension()
int	getNoOfSamples() Get the number of samples in a frame, all frames in a file have a set number of samples as defined by their MPEG Versiona and Layer
int	getNumberOfChannels() Gets the number of channels
int	getPaddingLength() Gets the paddingLength attribute of the MPEGFrame object
java.lang.Integer	getSamplingRate()
int	getVersion() Gets the mPEGVersion attribute of the MPEGFrame object
java.lang.String	getVersionAsString()
boolean	isCopyrighted()
static boolean	isMPEGFrame(java.nio.ByteBuffer bb) Gets the MPEGFrame attribute of the MPEGFrame object
boolean	isOriginal()
boolean	isPadding()
boolean	isPrivate()
boolean	isProtected()
boolean	isVariableBitRate()
static MPEGFrameHeader	parseMPEGHeader(java.nio.ByteBuffer bb) Parse the MPEGFrameHeader of an MP3File, file pointer returns at end of the frame header
private void	setBitrate() Get the setBitrate of this frame
private void	setChannelMode() Set the Mpeg channel mode of this frame as a constant (see constants)
private void	setCopyrighted() Gets the copyrighted attribute of the MPEGFrame object
private void	setEmphasis() Get the setEmphasis mode of this frame in a string representation
private void	setLayer() Get the layer version of this frame as a constant int value (see constants)
private void	setModeExtension() Sets the string representation of the mode extension of this frame
private void	setOriginal() Sets the original attribute of the MPEGFrame object
private void	setPadding() Set whether this frame uses padding bytes
private void	setPrivate() Sets the private attribute of the MPEGFrame object
private void	setProtected() Sets the protected attribute of the MPEGFrame object
private void	setSamplingRate() set the sampling rate in Hz of this frame
private void	setVersion() Set the version of this frame as an int value (see constants)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

BYTE_1

private static final int BYTE_1

Constants for MP3 Frame header, each frame has a basic header of 4 bytes

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Constant Field Values

BYTE_2

private static final int BYTE_2

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Constant Field Values

BYTE_3

private static final int BYTE_3

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Constant Field Values

BYTE_4

private static final int BYTE_4

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Constant Field Values

HEADER_SIZE

public static final int HEADER_SIZE

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Constant Field Values

SYNC_SIZE

public static final int SYNC_SIZE

Sync Value to identify the start of an MPEGFrame

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Constant Field Values

SYNC_BYTE1

public static final int SYNC_BYTE1

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Constant Field Values

SYNC_BYTE2

public static final int SYNC_BYTE2

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Constant Field Values

header

private static final byte[] header

mpegVersionMap

public static final java.util.Map<java.lang.Integer,java.lang.String> mpegVersionMap

Constants for MPEG Version

VERSION_2_5

public static final int VERSION_2_5

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Constant Field Values

VERSION_2

public static final int VERSION_2

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Constant Field Values

VERSION_1

public static final int VERSION_1

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mpegLayerMap

public static final java.util.Map<java.lang.Integer,java.lang.String> mpegLayerMap

Constants for MPEG Layer

LAYER_I

public static final int LAYER_I

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Constant Field Values

LAYER_II

public static final int LAYER_II

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LAYER_III

public static final int LAYER_III

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LAYER_I_SLOT_SIZE

public static final int LAYER_I_SLOT_SIZE

Slot Size is dependent on Layer

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Constant Field Values

LAYER_II_SLOT_SIZE

public static final int LAYER_II_SLOT_SIZE

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LAYER_III_SLOT_SIZE

public static final int LAYER_III_SLOT_SIZE

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Constant Field Values

bitrateMap

private static final java.util.Map<java.lang.Integer,java.lang.Integer> bitrateMap

Bit Rates, the setBitrate varies for different Version and Layer

modeMap

protected static final java.util.Map<java.lang.Integer,java.lang.String> modeMap

Constants for Channel mode

MODE_STEREO

public static final int MODE_STEREO

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Constant Field Values

MODE_JOINT_STEREO

public static final int MODE_JOINT_STEREO

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MODE_DUAL_CHANNEL

public static final int MODE_DUAL_CHANNEL

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Constant Field Values

MODE_MONO

public static final int MODE_MONO

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Constant Field Values

emphasisMap

private static final java.util.Map<java.lang.Integer,java.lang.String> emphasisMap

Constants for Emphasis

EMPHASIS_NONE

public static final int EMPHASIS_NONE

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Constant Field Values

EMPHASIS_5015MS

public static final int EMPHASIS_5015MS

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Constant Field Values

EMPHASIS_RESERVED

public static final int EMPHASIS_RESERVED

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Constant Field Values

EMPHASIS_CCITT

public static final int EMPHASIS_CCITT

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Constant Field Values

modeExtensionMap

private static final java.util.Map<java.lang.Integer,java.lang.String> modeExtensionMap

MODE_EXTENSION_NONE

private static final int MODE_EXTENSION_NONE

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Constant Field Values

MODE_EXTENSION_ONE

private static final int MODE_EXTENSION_ONE

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MODE_EXTENSION_TWO

private static final int MODE_EXTENSION_TWO

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MODE_EXTENSION_THREE

private static final int MODE_EXTENSION_THREE

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Constant Field Values

modeExtensionLayerIIIMap

private static final java.util.Map<java.lang.Integer,java.lang.String> modeExtensionLayerIIIMap

MODE_EXTENSION_OFF_OFF

private static final int MODE_EXTENSION_OFF_OFF

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Constant Field Values

MODE_EXTENSION_ON_OFF

private static final int MODE_EXTENSION_ON_OFF

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MODE_EXTENSION_OFF_ON

private static final int MODE_EXTENSION_OFF_ON

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MODE_EXTENSION_ON_ON

private static final int MODE_EXTENSION_ON_ON

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Constant Field Values

samplingRateMap

private static final java.util.Map<java.lang.Integer,java.util.Map<java.lang.Integer,java.lang.Integer>> samplingRateMap

Sampling Rate in Hz

samplingV1Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplingV1Map

samplingV2Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplingV2Map

samplingV25Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplingV25Map

samplesPerFrameMap

private static final java.util.Map<java.lang.Integer,java.util.Map<java.lang.Integer,java.lang.Integer>> samplesPerFrameMap

samplesPerFrameV1Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplesPerFrameV1Map

samplesPerFrameV2Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplesPerFrameV2Map

samplesPerFrameV25Map

private static final java.util.Map<java.lang.Integer,java.lang.Integer> samplesPerFrameV25Map

SCALE_BY_THOUSAND

private static final int SCALE_BY_THOUSAND

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Constant Field Values

LAYER_I_FRAME_SIZE_COEFFICIENT

private static final int LAYER_I_FRAME_SIZE_COEFFICIENT

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LAYER_II_FRAME_SIZE_COEFFICIENT

private static final int LAYER_II_FRAME_SIZE_COEFFICIENT

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LAYER_III_FRAME_SIZE_COEFFICIENT

private static final int LAYER_III_FRAME_SIZE_COEFFICIENT

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Constant Field Values

MASK_MP3_ID

private static final int MASK_MP3_ID

MP3 Frame Header bit mask

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Constant Field Values

MASK_MP3_VERSION

private static final int MASK_MP3_VERSION

MP3 version, confusingly for MP3s the version is 1.

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Constant Field Values

MASK_MP3_LAYER

private static final int MASK_MP3_LAYER

MP3 Layer, for MP3s the Layer is 3

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Constant Field Values

MASK_MP3_PROTECTION

private static final int MASK_MP3_PROTECTION

Does it include a CRC Checksum at end of header, this can be used to check the header.

See Also:

Constant Field Values

MASK_MP3_BITRATE

private static final int MASK_MP3_BITRATE

The setBitrate of this MP3

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Constant Field Values

MASK_MP3_FREQUENCY

private static final int MASK_MP3_FREQUENCY

The sampling/frequency rate

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Constant Field Values

MASK_MP3_PADDING

private static final int MASK_MP3_PADDING

An extra padding bit is sometimes used to make sure frames are exactly the right length

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Constant Field Values

MASK_MP3_PRIVACY

private static final int MASK_MP3_PRIVACY

Private bit set, for application specific

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Constant Field Values

MASK_MP3_MODE

private static final int MASK_MP3_MODE

Channel Mode, Stero/Mono/Dual Channel

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MASK_MP3_MODE_EXTENSION

private static final int MASK_MP3_MODE_EXTENSION

MP3 Frame Header bit mask

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MASK_MP3_COPY

private static final int MASK_MP3_COPY

MP3 Frame Header bit mask

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MASK_MP3_HOME

private static final int MASK_MP3_HOME

MP3 Frame Header bit mask

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MASK_MP3_EMPHASIS

private static final int MASK_MP3_EMPHASIS

MP3 Frame Header bit mask

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Constant Field Values

mpegBytes

private byte[] mpegBytes

version

private int version

The version of this MPEG frame (see the constants)

versionAsString

private java.lang.String versionAsString

layer

private int layer

Contains the mpeg layer of this frame (see constants)

layerAsString

private java.lang.String layerAsString

bitRate

private java.lang.Integer bitRate

Bitrate of this frame

channelMode

private int channelMode

Channel Mode of this Frame (see constants)

channelModeAsString

private java.lang.String channelModeAsString

Channel Mode of this Frame As English String

emphasis

private int emphasis

Emphasis of this frame

emphasisAsString

private java.lang.String emphasisAsString

Emphasis mode string

modeExtension

private java.lang.String modeExtension

Mode Extension

isPadding

private boolean isPadding

Flag indicating if this frame has padding byte

isCopyrighted

private boolean isCopyrighted

Flag indicating if this frame contains copyrighted material

isOriginal

private boolean isOriginal

Flag indicating if this frame contains original material

isProtected

private boolean isProtected

Flag indicating if this frame is protected

isPrivate

private boolean isPrivate

Flag indicating if this frame is private

samplingRate

private java.lang.Integer samplingRate

Constructor Detail

MPEGFrameHeader

private MPEGFrameHeader()
                 throws InvalidAudioFrameException

Hide Constructor

Throws:

InvalidAudioFrameException

MPEGFrameHeader

private MPEGFrameHeader(byte[] b)
                 throws InvalidAudioFrameException

Try and create a new MPEG frame with the given byte array and decodes its contents If decoding header causes a problem it is not a valid header

Parameters:

b - the array of bytes representing this mpeg frame

Throws:

InvalidAudioFrameException - if does not match expected format

Method Detail

getLayer

public int getLayer()

Gets the layerVersion attribute of the MPEGFrame object

Returns:

The layerVersion value

getLayerAsString

public java.lang.String getLayerAsString()

setCopyrighted

private void setCopyrighted()

Gets the copyrighted attribute of the MPEGFrame object

setVersion

private void setVersion()
                 throws InvalidAudioFrameException

Set the version of this frame as an int value (see constants)

Throws:

InvalidAudioFrameException

setOriginal

private void setOriginal()

Sets the original attribute of the MPEGFrame object

setProtected

private void setProtected()

Sets the protected attribute of the MPEGFrame object

setPrivate

private void setPrivate()

Sets the private attribute of the MPEGFrame object

setBitrate

private void setBitrate()
                 throws InvalidAudioFrameException

Get the setBitrate of this frame

Throws:

InvalidAudioFrameException

setChannelMode

private void setChannelMode()
                     throws InvalidAudioFrameException

Set the Mpeg channel mode of this frame as a constant (see constants)

Throws:

InvalidAudioFrameException

setEmphasis

private void setEmphasis()
                  throws InvalidAudioFrameException

Get the setEmphasis mode of this frame in a string representation

Throws:

InvalidAudioFrameException

setPadding

private void setPadding()

Set whether this frame uses padding bytes

setLayer

private void setLayer()
               throws InvalidAudioFrameException

Get the layer version of this frame as a constant int value (see constants)

Throws:

InvalidAudioFrameException

setModeExtension

private void setModeExtension()
                       throws InvalidAudioFrameException

Sets the string representation of the mode extension of this frame

Throws:

InvalidAudioFrameException

setSamplingRate

private void setSamplingRate()
                      throws InvalidAudioFrameException

set the sampling rate in Hz of this frame

Throws:

InvalidAudioFrameException

getNumberOfChannels

public int getNumberOfChannels()

Gets the number of channels

Returns:

The setChannelMode value

getChannelMode

public int getChannelMode()

getChannelModeAsString

public java.lang.String getChannelModeAsString()

getVersion

public int getVersion()

Gets the mPEGVersion attribute of the MPEGFrame object

Returns:

The mPEGVersion value

getVersionAsString

public java.lang.String getVersionAsString()

getPaddingLength

public int getPaddingLength()

Gets the paddingLength attribute of the MPEGFrame object

Returns:

The paddingLength value

getBitRate

public java.lang.Integer getBitRate()

getSamplingRate

public java.lang.Integer getSamplingRate()

getFrameLength

public int getFrameLength()

getNoOfSamples

public int getNoOfSamples()

Get the number of samples in a frame, all frames in a file have a set number of samples as defined by their MPEG Versiona and Layer

Returns:

isPadding

public boolean isPadding()

isCopyrighted

public boolean isCopyrighted()

isOriginal

public boolean isOriginal()

isProtected

public boolean isProtected()

isPrivate

public boolean isPrivate()

isVariableBitRate

public boolean isVariableBitRate()

getEmphasis

public int getEmphasis()

getEmphasisAsString

public java.lang.String getEmphasisAsString()

getModeExtension

public java.lang.String getModeExtension()

parseMPEGHeader

public static MPEGFrameHeader parseMPEGHeader(java.nio.ByteBuffer bb)
                                       throws InvalidAudioFrameException

Parse the MPEGFrameHeader of an MP3File, file pointer returns at end of the frame header

Parameters:

bb - the byte buffer containing the header

Returns:

Throws:

InvalidAudioFrameException - if there is no header at this point

isMPEGFrame

public static boolean isMPEGFrame(java.nio.ByteBuffer bb)

Gets the MPEGFrame attribute of the MPEGFrame object

Parameters:

bb -

Returns:

The mPEGFrame value

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

a string represntation