javazoom.jl.decoder

Class Bitstream

java.lang.Object

javazoom.jl.decoder.Bitstream

public final class Bitstream
extends Object

The Bistream class is responsible for parsing an MPEG audio bitstream. REVIEW: much of the parsing currently occurs in the various decoders. This should be moved into this class and associated inner classes.

Field Summary

Fields

Modifier and Type	Field and Description
static int	BITSTREAM_ERROR The first bitstream error code.
static int	BITSTREAM_LAST
static int	INVALIDFRAME Frame data are missing.
static int	STREAM_EOF The end of the stream was reached.
static int	STREAM_ERROR A problem occurred reading from the stream.
static int	UNEXPECTED_EOF The end of the stream was reached prematurely.
static int	UNKNOWN_ERROR An undeterminable error occurred.
static int	UNKNOWN_SAMPLE_RATE The header describes an unknown sample rate.

Constructor Summary

Constructors

Constructor and Description
Bitstream(InputStream in) Construct a IBitstream that reads data from a given InputStream.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the Bitstream.
void	closeFrame() Close MP3 frame.
int	get_bits(int number_of_bits) Read bits from buffer into the lower bits of an unsigned int.
InputStream	getRawID3v2() Return raw ID3v2 frames + header.
Float	getReplayGainScale()
int	header_pos() Return position of the first audio header.
boolean	isSyncCurrentPosition(int syncmode) Determines if the next 4 bytes of the stream represent a frame header.
boolean	isSyncMark(int headerstring, int syncmode, int word)
protected BitstreamException	newBitstreamException(int errorcode)
protected BitstreamException	newBitstreamException(int errorcode, Throwable throwable)
int	readBits(int n)
int	readCheckedBits(int n)
Header	readFrame() Reads and parses the next frame from the input source.
void	unreadFrame() Unreads the bytes read from the frame.

Methods inherited from class java.lang.Object

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

Field Detail

BITSTREAM_ERROR

public static final int BITSTREAM_ERROR

The first bitstream error code. See the DecoderErrors interface for other bitstream error codes.

See Also:

Constant Field Values

UNKNOWN_ERROR

public static final int UNKNOWN_ERROR

An undeterminable error occurred.

See Also:

Constant Field Values

UNKNOWN_SAMPLE_RATE

public static final int UNKNOWN_SAMPLE_RATE

The header describes an unknown sample rate.

See Also:

Constant Field Values

STREAM_ERROR

public static final int STREAM_ERROR

A problem occurred reading from the stream.

See Also:

Constant Field Values

UNEXPECTED_EOF

public static final int UNEXPECTED_EOF

The end of the stream was reached prematurely.

See Also:

Constant Field Values

STREAM_EOF

public static final int STREAM_EOF

The end of the stream was reached.

See Also:

Constant Field Values

INVALIDFRAME

public static final int INVALIDFRAME

Frame data are missing.

See Also:

Constant Field Values

BITSTREAM_LAST

public static final int BITSTREAM_LAST

See Also:

Constant Field Values

Constructor Detail

Bitstream

public Bitstream(InputStream in)

Construct a IBitstream that reads data from a given InputStream.

Parameters:

in - The InputStream to read from.

Method Detail

header_pos

public int header_pos()

Return position of the first audio header.

Returns:

size of ID3v2 tag frames.

getRawID3v2

public InputStream getRawID3v2()

Return raw ID3v2 frames + header.

Returns:

ID3v2 InputStream or null if ID3v2 frames are not available.

getReplayGainScale

public Float getReplayGainScale()

close

public void close()
           throws BitstreamException

Close the Bitstream.

Throws:

BitstreamException

readFrame

public Header readFrame()
                 throws BitstreamException

Reads and parses the next frame from the input source.

Returns:

the Header describing details of the frame read, or null if the end of the stream has been reached.

Throws:

BitstreamException

unreadFrame

public void unreadFrame()
                 throws BitstreamException

Unreads the bytes read from the frame.

Throws:

BitstreamException

closeFrame

public void closeFrame()

Close MP3 frame.

isSyncCurrentPosition

public boolean isSyncCurrentPosition(int syncmode)
                              throws BitstreamException

Determines if the next 4 bytes of the stream represent a frame header.

Throws:

BitstreamException

readBits

public int readBits(int n)

readCheckedBits

public int readCheckedBits(int n)

newBitstreamException

protected BitstreamException newBitstreamException(int errorcode)

newBitstreamException

protected BitstreamException newBitstreamException(int errorcode,
                                       Throwable throwable)

isSyncMark

public boolean isSyncMark(int headerstring,
                 int syncmode,
                 int word)

get_bits

public int get_bits(int number_of_bits)

Read bits from buffer into the lower bits of an unsigned int. The LSB contains the latest read bit of the stream. (1 <= number_of_bits <= 16)