de.sciss.jump3r.mp3

Class VBRTag

java.lang.Object

de.sciss.jump3r.mp3.VBRTag

public class VBRTag
extends java.lang.Object

A Vbr header may be present in the ancillary data field of the first frame of an mp3 bitstream
The Vbr header (optionally) contains

• frames total number of audio frames in the bitstream
• bytes total number of bytes in the bitstream
• toc table of contents

toc (table of contents) gives seek points for random access.
The ith entry determines the seek point for i-percent duration.
seek point in bytes = (toc[i]/256.0) * total_bitstream_bytes
e.g. half duration seek point = (toc[50]/256.0) * total_bitstream_bytes

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAXFRAMESIZE (0xB40) the max freeformat 640 32kHz framesize.
static int	NUMTOCENTRIES

Constructor Summary

Constructors

Constructor and Description
VBRTag()

Method Summary

Modifier and Type	Method and Description
void	addVbrFrame(LameGlobalFlags gfp) Add VBR entry, used to fill the VBR TOC entries.
int	getLameTagFrame(LameGlobalFlags gfp, byte[] buffer)
VBRTagData	getVbrTag(byte[] buf) Get VBR tag information
void	InitVbrTag(LameGlobalFlags gfp) Initializes the header
int	putVbrTag(LameGlobalFlags gfp, java.io.RandomAccessFile stream) Write final VBR tag to the file.
void	setModules(Lame lame, BitStream bs, Version v)
void	updateMusicCRC(int[] crc, byte[] buffer, int bufferPos, int size)

Methods inherited from class java.lang.Object

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

Field Detail

NUMTOCENTRIES

public static final int NUMTOCENTRIES

See Also:

Constant Field Values

MAXFRAMESIZE

public static final int MAXFRAMESIZE

(0xB40) the max freeformat 640 32kHz framesize.

See Also:

Constant Field Values

Constructor Detail

VBRTag

public VBRTag()

Method Detail

setModules

public final void setModules(Lame lame,
                             BitStream bs,
                             Version v)

addVbrFrame

public final void addVbrFrame(LameGlobalFlags gfp)

Add VBR entry, used to fill the VBR TOC entries.

Parameters:

gfp - global flags

getVbrTag

public final VBRTagData getVbrTag(byte[] buf)

Get VBR tag information

Parameters:

buf - header to analyze

bufPos - offset into the header

Returns:

VBR tag data

InitVbrTag

public final void InitVbrTag(LameGlobalFlags gfp)

Initializes the header

Parameters:

gfp - global flags

updateMusicCRC

public final void updateMusicCRC(int[] crc,
                                 byte[] buffer,
                                 int bufferPos,
                                 int size)

getLameTagFrame

public final int getLameTagFrame(LameGlobalFlags gfp,
                                 byte[] buffer)

putVbrTag

public final int putVbrTag(LameGlobalFlags gfp,
                           java.io.RandomAccessFile stream)
                    throws java.io.IOException

Write final VBR tag to the file.

Parameters:

gfp - global flags

stream - stream to add the VBR tag to

Returns:

0 (OK), -1 else

Throws:

java.io.IOException - I/O error