helliker.id3
Class XingVBRHeader

java.lang.Object
  helliker.id3.XingVBRHeader

public class XingVBRHeader

extends java.lang.Object

Field Summary

private int	avgBitrate
private boolean	exists
private int	FLAGS_SIZE
private int	HEAD_SIZE
private java.lang.String	HEAD_START
private int	length
private int	numBytes
private int	numFrames
private int	playingTime
private double[]	TIMEPERFRAME_TABLE
private byte[]	toc
private int	TOC_SIZE
private int	vbrScale

Constructor Summary

XingVBRHeader(java.io.RandomAccessFile raf, long offset, int layer, int mpegVersion, int sampleRate, int channelMode)
Looks for a Xing VBR header in the file.

Method Summary

private void	calcValues(int layer, int mpegVersion, int sampleRate) Calculates the playing time and the average bitrate.
private boolean	checkHeader(java.io.RandomAccessFile raf, long offset, int channelMode, int mpegVersion) Checks to see if a xing header is in this file
int	getAvgBitrate() Returns the average bit rate of the mpeg file if a Xing header exists and -1 otherwise.
int	getLength() Returns the length (in bytes) of this Xing VBR header.
int	getNumBytes() Returns the number of data bytes in the mpeg frames.
int	getNumFrames() Returns the number of MPEG frames in the file passed to the constructor.
int	getPlayingTime() Returns the calculated playing time of the mpeg file if a Xing header exists and -1 otherwise.
byte[]	getTOC() Returns the toc used to seek to an area of this VBR file.
int	getVBRScale() Returns the VBR scale used to generate this VBR file.
boolean	headerExists() Returns true if a Xing VBR header was found in the file passed to the constructor.
private void	readHeader(java.io.RandomAccessFile raf) Parses the header data.
java.lang.String	toString() Return a string representation of this object.

Methods inherited from class java.lang.Object

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

Field Detail

HEAD_START

private final java.lang.String HEAD_START

See Also:

Constant Field Values

HEAD_SIZE

private final int HEAD_SIZE

See Also:

Constant Field Values

FLAGS_SIZE

private final int FLAGS_SIZE

See Also:

Constant Field Values

TOC_SIZE

private final int TOC_SIZE

See Also:

Constant Field Values

TIMEPERFRAME_TABLE

private final double[] TIMEPERFRAME_TABLE

numFrames

private int numFrames

numBytes

private int numBytes

vbrScale

private int vbrScale

toc

private byte[] toc

avgBitrate

private int avgBitrate

playingTime

private int playingTime

length

private int length

exists

private boolean exists

Constructor Detail

XingVBRHeader

public XingVBRHeader(java.io.RandomAccessFile raf,
                     long offset,
                     int layer,
                     int mpegVersion,
                     int sampleRate,
                     int channelMode)
              throws java.io.IOException,
                     CorruptHeaderException

Looks for a Xing VBR header in the file. If it is found then that means this is a variable bit rate file and all the data in the header will be parsed.

Parameters:

raf - the file to read from

offset - the location of the first mpeg frame

layer - the layer value read by the MPEGAudioFrameHeader

mpegVersion - the version value read by the MPEGAudioFrameHeader

sampleRate - the sample rate read by the MPEGAudioFrameHeader

channelMode - the channel mode read by the MPEGAudioFrameHeader

Throws:

java.io.IOException - if an error occurs

CorruptHeaderException - if an error occurs

Method Detail

checkHeader

private boolean checkHeader(java.io.RandomAccessFile raf,
                            long offset,
                            int channelMode,
                            int mpegVersion)
                     throws java.io.IOException

Checks to see if a xing header is in this file

Parameters:

raf - the file to read from

offset - the location of the first mpeg frame

mpegVersion - the version value read by the MPEGAudioFrameHeader

channelMode - the channel mode read by the MPEGAudioFrameHeader

Returns:

true if a xing header exists

Throws:

java.io.IOException - if an error occurs

readHeader

private void readHeader(java.io.RandomAccessFile raf)
                 throws java.io.IOException,
                        CorruptHeaderException

Parses the header data.

Parameters:

raf - the file to read from (pointing after the "Xing")

Throws:

java.io.IOException - if an error occurs

CorruptHeaderException - if an error occurs

calcValues

private void calcValues(int layer,
                        int mpegVersion,
                        int sampleRate)

Calculates the playing time and the average bitrate.

Parameters:

layer - the layer value read by the MPEGAudioFrameHeader

mpegVersion - the version value read by the MPEGAudioFrameHeader

sampleRate - the sample rate read by the MPEGAudioFrameHeader

headerExists

public boolean headerExists()

Returns true if a Xing VBR header was found in the file passed to the constructor.

Returns:

true if a Xinb VBR header was found

getNumFrames

public int getNumFrames()

Returns the number of MPEG frames in the file passed to the constructor. If a header is not found, -1 is returned.

Returns:

the number of MPEG frames

getNumBytes

public int getNumBytes()

Returns the number of data bytes in the mpeg frames. If a header is not found, -1 is returned.

Returns:

the number of data bytes in the mpeg frames

getVBRScale

public int getVBRScale()

Returns the VBR scale used to generate this VBR file. If a header is not found, -1 is returned.

Returns:

the VBR scale used to generate this VBR file

getTOC

public byte[] getTOC()

Returns the toc used to seek to an area of this VBR file. If a header is not found an empty array is returned.

Returns:

the toc used to seek to an area of this VBR file

getAvgBitrate

public int getAvgBitrate()

Returns the average bit rate of the mpeg file if a Xing header exists and -1 otherwise.

Returns:

the average bit rate (in kbps)

getPlayingTime

public int getPlayingTime()

Returns the calculated playing time of the mpeg file if a Xing header exists and -1 otherwise.

Returns:

the playing time (in seconds) of the mpeg file

toString

public java.lang.String toString()

Return a string representation of this object. Includes all information read in and computed.

Returns:

a string representation of this object

getLength

public int getLength()

Returns the length (in bytes) of this Xing VBR header.

Returns:

the length of this Xing VBR header