mediaframe.mpeg1.audio.player
Class BigPipedInputStream

java.lang.Object
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  +--java.io.InputStream
        |
        +--mediaframe.mpeg1.audio.player.BigPipedInputStream

public class BigPipedInputStream

extends java.io.InputStream

The BigPipedInputStream represents the Piped Input Stream. It receives the input data from a BigPipedOutputStream, puts them into the circle data buffer and returns when a client requests for the next portion of the data.
This class responds for convertion the audio samples into the uLaw representation for eight-bit eight khz ulaw decoder (browser).
This class implements volume and mute features (multiplies the digital sound data word by a volume value or returns uLaw zero if the mute equals true).

Version:

1.0 26.07.2002

Author:

Konstantin Belous

Field Summary

private short[]	buffer The circle buffer of audio samples.
(package private) boolean	bufferFilled True, if the decoding of the audio stream has been finished and the circle buffer has been filled with the audio samples.
private boolean	firstPause True for the first pause in the movie playback (normally if the player doesn't played any frames).
private int	inp The pointer for read in the circle buffer.
private boolean	isClosedByReader True, if the pipe has been already closed by BigPipedInputStream.
(package private) boolean	isClosedByWriter True, if the pipe has been already closed by BigPipedOutputStream.
private int	lastOutp The value of the pointer for write in the circle buffer during last read from the stream.
static boolean	mute The mute state of the audio player.
private int	outp The pointer for write in the circle buffer.
(package private) BigPipedOutputStream	outputPipe The reference to the output stream in the pipe.
boolean	playing True if the audio player is playing the sound, false if the playback is paused.
static int	ULAW_BIAS Constanta used in the linear -> uLaw computation.
static int	ULAW_CLIP Constanta used in the linear -> uLaw computation.
static int[]	ULAW_LUT Table of (roughly) logarithms base 2, used in the linear -> uLaw computation.
static byte	ULAW_ZERO uLaw representation of zero.
static int	Volume The volume of the audio signal.
private int	waiting_reader The amount of threads which waits the reader side.
private int	waiting_writer The amount of threads which waits the writer side.

Fields inherited from class java.io.InputStream

Constructor Summary

BigPipedInputStream(int nBufferSize)
Constructs a BigPipedInputStream class with the specified buffer size.

Method Summary

void	close() Closes the BigPipedInputStream
private static int[]	computeUlawLut() Compute logarithm (roughly) table used in the linear -> uLaw mapping.
void	connect(BigPipedOutputStream src) Connects this object with the specified BigPipedOutputStream object in the pipe.
int	freeInBuffer() Returns the amount of audio samples that could be placed into the circle buffer.
void	notify_reader() Notifies the reader side for about the next portion of data.
void	notify_writer() Notifies the writer side that the circle buffer is ready for receiving samples.
int	read() Reads uLaw representation of the next sample of sound data from the circle buffer.
int	read(byte[] b, int off, int len) Reads uLaw representations of len samples of sound data from the circle buffer into the array b starting from the offset off.
(package private) void	receive(short b) Places the next auduo sample into the circle buffer.
void	wait_for_reader() Waits the reader until the circle buffer will be ready for receiving samples.
void	wait_for_writer() Waits the writer for the next portion of data.

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Field Detail

inp

private int inp

The pointer for read in the circle buffer.

outp

private int outp

The pointer for write in the circle buffer.

lastOutp

private int lastOutp

The value of the pointer for write in the circle buffer during last read from the stream.

buffer

private short[] buffer

The circle buffer of audio samples.

isClosedByWriter

boolean isClosedByWriter

True, if the pipe has been already closed by BigPipedOutputStream.

isClosedByReader

private boolean isClosedByReader

True, if the pipe has been already closed by BigPipedInputStream.

outputPipe

BigPipedOutputStream outputPipe

The reference to the output stream in the pipe.

playing

public boolean playing

True if the audio player is playing the sound, false if the playback is paused.

Volume

public static int Volume

The volume of the audio signal.

mute

public static boolean mute

The mute state of the audio player.

bufferFilled

boolean bufferFilled

True, if the decoding of the audio stream has been finished and the circle buffer has been filled with the audio samples.

firstPause

private boolean firstPause

True for the first pause in the movie playback (normally if the player doesn't played any frames).

waiting_reader

private int waiting_reader

The amount of threads which waits the reader side.

waiting_writer

private int waiting_writer

The amount of threads which waits the writer side.

ULAW_ZERO

public static final byte ULAW_ZERO

uLaw representation of zero. (Both 127 or 255 map to zero.)

See Also:

Constant Field Values

ULAW_BIAS

public static final int ULAW_BIAS

Constanta used in the linear -> uLaw computation.

See Also:

Constant Field Values

ULAW_CLIP

public static final int ULAW_CLIP

Constanta used in the linear -> uLaw computation.

See Also:

Constant Field Values

ULAW_LUT

public static final int[] ULAW_LUT

Table of (roughly) logarithms base 2, used in the linear -> uLaw computation.

Constructor Detail

BigPipedInputStream

public BigPipedInputStream(int nBufferSize)

Constructs a BigPipedInputStream class with the specified buffer size.

Parameters:

nBufferSize - the size of a circle buffer.

Method Detail

read

public int read()
         throws java.io.IOException

Reads uLaw representation of the next sample of sound data from the circle buffer. Implements the volume feature (multiplies the sample value by a volume value) or returns uLaw zero value if the mute equals true.

Specified by:

read in class java.io.InputStream

Returns:

one byte from the circle buffer.

Throws:

java.io.IOException - raises if a error occurs.

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException

Reads uLaw representations of len samples of sound data from the circle buffer into the array b starting from the offset off. Implements the volume feature (multiplies the sample value by a volume value) or returns uLaw zero value if the mute equals true.

Overrides:

read in class java.io.InputStream

Parameters:

b - the array into which the data is read.

off - the start offset in the array b into which the data is written.

len - the maximum amount of bytes to read.

Returns:

the total amount of bytes read into the array, or -1 if there is no more data because the end of the file has been reached.

Throws:

java.io.IOException - raises if a error occurs.

freeInBuffer

public int freeInBuffer()

Returns the amount of audio samples that could be placed into the circle buffer.

connect

public void connect(BigPipedOutputStream src)

Connects this object with the specified BigPipedOutputStream object in the pipe.

Parameters:

src - the BigPipedOutputStream object.

close

public void close()

Closes the BigPipedInputStream

Overrides:

close in class java.io.InputStream

receive

void receive(short b)
       throws java.io.IOException

Places the next auduo sample into the circle buffer.

Parameters:

b - the next audio sample.

Throws:

java.io.IOException - raises if a error occurs.

notify_writer

public void notify_writer()

Notifies the writer side that the circle buffer is ready for receiving samples.

wait_for_reader

public void wait_for_reader()
                     throws java.io.InterruptedIOException

Waits the reader until the circle buffer will be ready for receiving samples.

Throws:

java.io.InterruptedIOException - when the current process has been interrupted by the another process.

notify_reader

public void notify_reader()

Notifies the reader side for about the next portion of data.

wait_for_writer

public void wait_for_writer()
                     throws java.io.InterruptedIOException

Waits the writer for the next portion of data.

Throws:

java.io.InterruptedIOException - when the current process has been interrupted by the another process.

computeUlawLut

private static int[] computeUlawLut()

Compute logarithm (roughly) table used in the linear -> uLaw mapping.

We compute this table (rather than store it) mostly to make the .class file a bit smaller, (and also to help avoid typos.)