com.neoworks.mpeg
Class XingVBRHeader

java.lang.Object
  |
  +--com.neoworks.mpeg.XingVBRHeader

public class XingVBRHeader

extends java.lang.Object

Reads information from a Xing variable bitrate info header. Thanks to the Scilla project (http://www.xs4all.nl/~rwvtveer/scilla/) for code ideas.

Version:

$Id: XingVBRHeader.java,v 1.4 2002/06/24 17:21:27 nigel Exp $

Author:

Nigel Atkinson (nigel@neoworks.com)

, Jonathan Hilliker

Constructor Summary

XingVBRHeader(byte[] data, long offset, int layer, int mpegVersion, int sampleRate, int channelMode)
Looks for a Xing VBR header in the file.

Method Summary

int	getAvgBitrate() Returns the average bit rate of the mpeg file if a Xing header exists and -1 otherwise.
int	getHeaderOffset() Get the offset from the end of the MPEG header to the beginning of the VBR header in bytes
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.
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

Constructor Detail

XingVBRHeader

public XingVBRHeader(byte[] data,
                     long offset,
                     int layer,
                     int mpegVersion,
                     int sampleRate,
                     int channelMode)

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:

data - The MPEG frame data to extract the header 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

Method Detail

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)

getHeaderOffset

public int getHeaderOffset()

Get the offset from the end of the MPEG header to the beginning of the VBR header in bytes

Returns:

The offset in bytes

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.

Overrides:

toString in class java.lang.Object

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