org.jaudiotagger.audio.mp3
Class XingFrame

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

public class XingFrame
extends java.lang.Object

Xing Frame

In some MP3s which variable bit rate the first frame in the file contains a special frame called a Xing Frame, instead of audio data. This is used to store additional information about the file. The most important aspect for this library is details allowing us to determine the bitrate of a Variable Bit Rate VBR file without having to process the whole file.

Xing VBR Tag data format is 120 bytes long 4 bytes for Header Tag 4 bytes for Header Flags 4 bytes for FRAME SIZE 4 bytes for AUDIO_SIZE 100 bytes for entry (NUMTOCENTRIES) 4 bytes for VBR SCALE. a VBR quality indicator: 0=best 100=worst

It my then contain a Lame Frame ( a Lame frame is in essence an extended Xing Frame

Field Summary

private int	audioSize
private static int	BYTE_1
private static int	BYTE_2
private static int	BYTE_3
private static int	BYTE_4
private int	frameCount
private static java.nio.ByteBuffer	header
private boolean	isAudioSizeEnabled
private boolean	isFrameCountEnabled
private LameFrame	lameFrame
static int	MAX_BUFFER_SIZE_NEEDED_TO_READ_XING
private static int	MPEG_VERSION_1_MODE_MONO_OFFSET
private static int	MPEG_VERSION_1_MODE_STEREO_OFFSET
private static int	MPEG_VERSION_2_MODE_MONO_OFFSET
private static int	MPEG_VERSION_2_MODE_STEREO_OFFSET
private boolean	vbr
private static int	XING_AUDIOSIZE_BUFFER_SIZE
private static byte[]	XING_CBR_ID Use when it is a CBR (Constant Bitrate) file
private static int	XING_FLAG_BUFFER_SIZE
private static int	XING_FRAMECOUNT_BUFFER_SIZE
private static int	XING_HEADER_BUFFER_SIZE
private static int	XING_IDENTIFIER_BUFFER_SIZE
private static byte[]	XING_VBR_ID Use when it is a VBR (Variable Bitrate) file

Constructor Summary

private

XingFrame() Read the Xing Properties from the buffer

Method Summary

int	getAudioSize()
int	getFrameCount()
LameFrame	getLameFrame()
boolean	isAudioSizeEnabled()
boolean	isFrameCountEnabled()
boolean	isVbr() Is this XingFrame detailing a varaible bit rate MPEG
static boolean	isXingFrame(java.nio.ByteBuffer bb, MPEGFrameHeader mpegFrameHeader) IS this a Xing frame
static XingFrame	parseXingFrame() Parse the XingFrame of an MP3File, cannot be called until we have validated that this is a XingFrame
private void	setAudioSize() Set size of AudioData
private void	setFrameCount() Set count of frames
private void	setVbr() Set whether or not VBR, (Xing can also be used for CBR though this is less useful)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

MPEG_VERSION_1_MODE_MONO_OFFSET

private static final int MPEG_VERSION_1_MODE_MONO_OFFSET

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Constant Field Values

MPEG_VERSION_1_MODE_STEREO_OFFSET

private static final int MPEG_VERSION_1_MODE_STEREO_OFFSET

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Constant Field Values

MPEG_VERSION_2_MODE_MONO_OFFSET

private static final int MPEG_VERSION_2_MODE_MONO_OFFSET

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Constant Field Values

MPEG_VERSION_2_MODE_STEREO_OFFSET

private static final int MPEG_VERSION_2_MODE_STEREO_OFFSET

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Constant Field Values

XING_HEADER_BUFFER_SIZE

private static final int XING_HEADER_BUFFER_SIZE

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Constant Field Values

XING_IDENTIFIER_BUFFER_SIZE

private static final int XING_IDENTIFIER_BUFFER_SIZE

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Constant Field Values

XING_FLAG_BUFFER_SIZE

private static final int XING_FLAG_BUFFER_SIZE

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Constant Field Values

XING_FRAMECOUNT_BUFFER_SIZE

private static final int XING_FRAMECOUNT_BUFFER_SIZE

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Constant Field Values

XING_AUDIOSIZE_BUFFER_SIZE

private static final int XING_AUDIOSIZE_BUFFER_SIZE

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Constant Field Values

MAX_BUFFER_SIZE_NEEDED_TO_READ_XING

public static final int MAX_BUFFER_SIZE_NEEDED_TO_READ_XING

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Constant Field Values

BYTE_1

private static final int BYTE_1

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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

XING_VBR_ID

private static final byte[] XING_VBR_ID

Use when it is a VBR (Variable Bitrate) file

XING_CBR_ID

private static final byte[] XING_CBR_ID

Use when it is a CBR (Constant Bitrate) file

header

private static java.nio.ByteBuffer header

vbr

private boolean vbr

isFrameCountEnabled

private boolean isFrameCountEnabled

frameCount

private int frameCount

isAudioSizeEnabled

private boolean isAudioSizeEnabled

audioSize

private int audioSize

lameFrame

private LameFrame lameFrame

Constructor Detail

XingFrame

private XingFrame()

Read the Xing Properties from the buffer

Method Detail

getLameFrame

public LameFrame getLameFrame()

setVbr

private void setVbr()

Set whether or not VBR, (Xing can also be used for CBR though this is less useful)

setFrameCount

private void setFrameCount()

Set count of frames

isFrameCountEnabled

public final boolean isFrameCountEnabled()

Returns:

true if frameCount has been specified in header

getFrameCount

public final int getFrameCount()

Returns:

count of frames

setAudioSize

private void setAudioSize()

Set size of AudioData

isAudioSizeEnabled

public final boolean isAudioSizeEnabled()

Returns:

true if audioSize has been specified in header

getAudioSize

public final int getAudioSize()

Returns:

size of audio data in bytes

parseXingFrame

public static XingFrame parseXingFrame()
                                throws InvalidAudioFrameException

Parse the XingFrame of an MP3File, cannot be called until we have validated that this is a XingFrame

Returns:

Throws:

InvalidAudioFrameException

isXingFrame

public static boolean isXingFrame(java.nio.ByteBuffer bb,
                                  MPEGFrameHeader mpegFrameHeader)

IS this a Xing frame

Parameters:

bb -

mpegFrameHeader -

Returns:

true if this is a Xing frame

isVbr

public final boolean isVbr()

Is this XingFrame detailing a varaible bit rate MPEG

Returns:

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

a string represntation