org.xiph.speex.spi
Class Speex2PcmAudioInputStream

java.lang.Object
  java.io.InputStream
      javax.sound.sampled.AudioInputStream
          org.xiph.speex.spi.FilteredAudioInputStream
              org.xiph.speex.spi.Speex2PcmAudioInputStream

public class Speex2PcmAudioInputStream

extends FilteredAudioInputStream

Converts an Ogg Speex bitstream into a PCM 16bits/sample audio stream.

Version:

$Revision: 1.9 $

Author:

Marc Gimpel, Wimba S.A. (marc@wimba.com)

Nested Class Summary

Nested classes inherited from class javax.sound.sampled.AudioInputStream

Field Summary

private Bits	bits Speex bit packing and unpacking class.
private int	channelCount The number of audio channels (1=mono, 2=stereo).
private float[]	decodedData Array containing the decoded audio samples.
private Decoder	decoder Speex Decoder.
private boolean	first Flag to indicate if this is the first time a decode method is called.
private int	frameSize The frame size, in samples.
private int	framesPerPacket The number of Speex frames that will be put in each Ogg packet.
private byte[]	outputData Array containing the decoded audio samples converted into bytes.
private int	packetCount The number of Ogg packets that have been decoded in the current page.
private byte[]	packetSizes Array containing the sizes of Ogg packets in the current page.
private int	packetsPerOggPage The number of Ogg packets that are in each Ogg page.
private int	sampleRate The sample rate of the audio, in samples per seconds (Hz).
private int	streamSerialNumber A unique serial number that identifies the Ogg stream.

Fields inherited from class org.xiph.speex.spi.FilteredAudioInputStream

buf, count, DEFAULT_BUFFER_SIZE, in, marklimit, markpos, pos, prebuf, precount, prepos

Fields inherited from class javax.sound.sampled.AudioInputStream

format, frameLength, framePos

Fields inherited from class java.io.InputStream

Constructor Summary

Speex2PcmAudioInputStream(java.io.InputStream in, javax.sound.sampled.AudioFormat format, long length)
Constructor

Speex2PcmAudioInputStream(java.io.InputStream in, javax.sound.sampled.AudioFormat format, long length, int size)
Constructor

Method Summary

int	available() Returns the number of bytes that can be read from this inputstream without blocking.
protected void	decode(byte[] data, int offset, int len) This is where the actual decoding takes place.
protected void	fill() Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks.
protected void	initDecoder() Initialise the Speex Decoder after reading the Ogg Header.
private static int	readInt(byte[] data, int offset) Converts Little Endian (Windows) bytes to an int (Java uses Big Endian).
private void	readOggPageHeader() Read the Ogg Page header and extract the speex packet sizes.

Methods inherited from class org.xiph.speex.spi.FilteredAudioInputStream

close, makeSpace, mark, markSupported, read, read, reset, skip

Methods inherited from class javax.sound.sampled.AudioInputStream

getFormat, getFrameLength, read

Methods inherited from class java.lang.Object

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

Field Detail

sampleRate

private int sampleRate

The sample rate of the audio, in samples per seconds (Hz).

channelCount

private int channelCount

The number of audio channels (1=mono, 2=stereo).

decodedData

private float[] decodedData

Array containing the decoded audio samples.

outputData

private byte[] outputData

Array containing the decoded audio samples converted into bytes.

bits

private Bits bits

Speex bit packing and unpacking class.

decoder

private Decoder decoder

Speex Decoder.

frameSize

private int frameSize

The frame size, in samples.

framesPerPacket

private int framesPerPacket

The number of Speex frames that will be put in each Ogg packet.

streamSerialNumber

private int streamSerialNumber

A unique serial number that identifies the Ogg stream.

packetsPerOggPage

private int packetsPerOggPage

The number of Ogg packets that are in each Ogg page.

packetCount

private int packetCount

The number of Ogg packets that have been decoded in the current page.

packetSizes

private byte[] packetSizes

Array containing the sizes of Ogg packets in the current page.

first

private boolean first

Flag to indicate if this is the first time a decode method is called.

Constructor Detail

Speex2PcmAudioInputStream

public Speex2PcmAudioInputStream(java.io.InputStream in,
                                 javax.sound.sampled.AudioFormat format,
                                 long length)

Constructor

Parameters:

in - the underlying input stream.

format - the target format of this stream's audio data.

length - the length in sample frames of the data in this stream.

Speex2PcmAudioInputStream

public Speex2PcmAudioInputStream(java.io.InputStream in,
                                 javax.sound.sampled.AudioFormat format,
                                 long length,
                                 int size)

Constructor

Parameters:

in - the underlying input stream.

format - the target format of this stream's audio data.

length - the length in sample frames of the data in this stream.

size - the buffer size.

Throws:

java.lang.IllegalArgumentException - if size <= 0.

Method Detail

initDecoder

protected void initDecoder()
                    throws java.io.IOException

Initialise the Speex Decoder after reading the Ogg Header.

 Ogg Header description
  0 -  3: capture_pattern
       4: stream_structure_version
       5: header_type_flag (2=bos: beginning of sream)
  6 - 13: absolute granule position
 14 - 17: stream serial number
 18 - 21: page sequence no
 22 - 25: page checksum
      26: page_segments
 27 -...: segment_table
 Speex Header description
  0 -  7: speex_string
  8 - 27: speex_version
 28 - 31: speex_version_id
 32 - 35: header_size
 36 - 39: rate
 40 - 43: mode (0=narrowband, 1=wb, 2=uwb)
 44 - 47: mode_bitstream_version
 48 - 51: nb_channels
 52 - 55: bitrate
 56 - 59: frame_size
 60 - 63: vbr
 64 - 67: frames_per_packet
 68 - 71: extra_headers
 72 - 75: reserved1
 76 - 79: reserved2
 

Throws:

java.io.IOException

fill

protected void fill()
             throws java.io.IOException

Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks. Assumes that it is being called by a synchronized method. This method also assumes that all data has already been read in, hence pos > count.

Overrides:

fill in class FilteredAudioInputStream

Throws:

java.io.IOException

decode

protected void decode(byte[] data,
                      int offset,
                      int len)
               throws java.io.StreamCorruptedException

This is where the actual decoding takes place.

Parameters:

data - the array of data to decode.

offset - the offset from which to start reading the data.

len - the length of data to read from the array.

Throws:

java.io.StreamCorruptedException - If the input stream not valid Ogg Speex data.

available

public int available()
              throws java.io.IOException

Returns the number of bytes that can be read from this inputstream without blocking.

The available method of FilteredAudioInputStream returns the sum of the the number of bytes remaining to be read in the buffer (count - pos). The result of calling the available method of the underlying inputstream is not used, as this data will have to be filtered, and thus may not be the same size after processing (although subclasses that do the filtering should override this method and use the amount of data available in the underlying inputstream).

Overrides:

available in class FilteredAudioInputStream

Returns:

the number of bytes that can be read from this inputstream without blocking.

Throws:

java.io.IOException - if an I/O error occurs.

See Also:

FilteredAudioInputStream.in

readOggPageHeader

private void readOggPageHeader()
                        throws java.io.IOException

Read the Ogg Page header and extract the speex packet sizes. Note: the checksum is ignores.

Throws:

java.io.IOException

readInt

private static int readInt(byte[] data,
                           int offset)

Converts Little Endian (Windows) bytes to an int (Java uses Big Endian).

Parameters:

data - the data to read.

offset - the offset from which to start reading.

Returns:

the integer value of the reassembled bytes.