audio
Class AudioCodecAlaw

java.lang.Object
  audio.AbstractCODEC
      audio.AudioCodecAlaw

All Implemented Interfaces:

AudioInterface

public class AudioCodecAlaw
extends AbstractCODEC

Converts a 16-bit linear PCM stream from and to 8-bit A-law.

Author:

Mikica B Kocic, based on Sun Microsystem's C source code.

Nested Class Summary

Nested classes/interfaces inherited from interface audio.AudioInterface

AudioInterface.Packetizer

Field Summary

private static int	QUANT_MASK
private int	sampleSize
private static int[]	seg_end
private static int	SEG_MASK
private static int	SEG_SHIFT
private static int	SIGN_BIT

Fields inherited from class audio.AbstractCODEC

audio, inputPcmBuf, outputPcmBuf

Constructor Summary

AudioCodecAlaw(AudioInterfacePCM audio)
Constructs A-Law CODEC above existing PCM audio interface

Method Summary

private static short	alaw2linear(byte alaw_value) Converts an 8-bit A-law value to 16-bit linear PCM
void	convertFromPCM(byte[] in, byte[] out) Decodes data from PCM, i.e. converts samples from CODEC to A-Law format.
void	convertToPCM(byte[] in, byte[] out) Encodes data to PCM, i.e. converts samples from A-Law to CODEC format.
int	getSampleSize() Returns the minimum sample size for use in creating buffers etc.
int	getVoicePduSubclass() Gets the VoicePDU subclass attribute of the AbstractAudio object
private static byte	linear2alaw(short pcm_value) Converts a 16-bit linear PCM value to 8-bit A-law

Methods inherited from class audio.AbstractCODEC

cleanUp, getByFormat, readWithTimestamp, setAudioSender, startPlay, startRecording, startRinging, stopPlay, stopRecording, stopRinging, writeBuffered, writeDirectly

Methods inherited from class java.lang.Object

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

Field Detail

sampleSize

private int sampleSize

SIGN_BIT

private static final int SIGN_BIT

See Also:

Constant Field Values

QUANT_MASK

private static final int QUANT_MASK

See Also:

Constant Field Values

SEG_SHIFT

private static final int SEG_SHIFT

See Also:

Constant Field Values

SEG_MASK

private static final int SEG_MASK

See Also:

Constant Field Values

seg_end

private static final int[] seg_end

Constructor Detail

AudioCodecAlaw

public AudioCodecAlaw(AudioInterfacePCM audio)

Constructs A-Law CODEC above existing PCM audio interface

Method Detail

getVoicePduSubclass

public int getVoicePduSubclass()

Gets the VoicePDU subclass attribute of the AbstractAudio object

Specified by:

getVoicePduSubclass in interface AudioInterface

Specified by:

getVoicePduSubclass in class AbstractCODEC

getSampleSize

public int getSampleSize()

Returns the minimum sample size for use in creating buffers etc.

convertToPCM

public void convertToPCM(byte[] in,
                         byte[] out)

Encodes data to PCM, i.e. converts samples from A-Law to CODEC format.

Specified by:

convertToPCM in class AbstractCODEC

convertFromPCM

public void convertFromPCM(byte[] in,
                           byte[] out)

Decodes data from PCM, i.e. converts samples from CODEC to A-Law format.

Specified by:

convertFromPCM in class AbstractCODEC

linear2alaw

private static byte linear2alaw(short pcm_value)

Converts a 16-bit linear PCM value to 8-bit A-law

alaw2linear

private static short alaw2linear(byte alaw_value)

Converts an 8-bit A-law value to 16-bit linear PCM