com.sun.speech.freetts.audio
Class JavaStreamingAudioPlayer

java.lang.Object
  com.sun.speech.freetts.audio.JavaStreamingAudioPlayer

All Implemented Interfaces:

AudioPlayer

public class JavaStreamingAudioPlayer

extends java.lang.Object

implements AudioPlayer

Streams audio to java audio. This class provides a low latency method of sending audio output through the javax.sound audio API. Audio data is sent in small sets to the audio system allowing it to be played soon after it is generated. Unfortunately, the current release of the JDK (JDK 1.4 beta 2) has a bug or two in the implementation of 'SourceDataLine.drain'. A workaround solution that sleep/waits on SourceDataLine.isActive is used here instead. To disable the work around (i.e use the real 'drain') set the property:

com.sun.speech.freetts.audio.AudioPlayer.drainWorksProperly; to true. If the workaround is enabled, the line.isActive method will be performed periodically. The period of the test can be controlled with:

com.sun.speech.freetts.audio.AudioPlayer.drainDelay"

The default if 5ms.

The property com.sun.speech.freetts.audio.AudioPlayer.bufferSize"

Controls the audio buffer size, it defaults to 8192

Even with this drain work around, there are some issues with this class. The workaround drain is not completely reliable. A resume following a pause does not always continue at the proper position in the audio. On a rare occasion, sound output will be repeated a number of times. This may be related to bug 4421330 in the Bug Parade database.

Constructor Summary

JavaStreamingAudioPlayer()
Constructs a default JavaStreamingAudioPlayer

Method Summary

void	begin(int size) Starts the output of a set of data.
void	cancel() Cancels currently playing audio.
void	close() Closes this audio player
boolean	drain() Waits for all queued audio to be played
boolean	end() Marks the end of a set of data.
javax.sound.sampled.AudioFormat	getAudioFormat() Gets the audio format for this player
long	getTime() Gets the amount of played since the last mark
float	getVolume() Returns the current volume.
void	pause() Pauses audio output
void	reset() Prepares for another batch of output.
void	resetTime() Resets the audio clock
void	resume() Resumes audio output
void	setAudioFormat(javax.sound.sampled.AudioFormat format) Sets the audio format for this player
void	setVolume(float volume) Sets the current volume.
void	showMetrics() Shows metrics for this audio player
void	startFirstSampleTimer() Starts the first sample timer
java.lang.String	toString() Returns the name of this audioplayer
boolean	write(byte[] audioData) Writes the given bytes to the audio stream
boolean	write(byte[] bytes, int offset, int size) Writes the given bytes to the audio stream

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaStreamingAudioPlayer

public JavaStreamingAudioPlayer()

Constructs a default JavaStreamingAudioPlayer

Method Detail

setAudioFormat

public void setAudioFormat(javax.sound.sampled.AudioFormat format)

Sets the audio format for this player

Specified by:

setAudioFormat in interface AudioPlayer

Parameters:

format - the audio format

Throws:

java.lang.UnsupportedOperationException - if the line cannot be opened with the given format

getAudioFormat

public javax.sound.sampled.AudioFormat getAudioFormat()

Gets the audio format for this player

Specified by:

getAudioFormat in interface AudioPlayer

Returns:

format the audio format

startFirstSampleTimer

public void startFirstSampleTimer()

Starts the first sample timer

Specified by:

startFirstSampleTimer in interface AudioPlayer

pause

public void pause()

Pauses audio output

Specified by:

pause in interface AudioPlayer

resume

public void resume()

Resumes audio output

Specified by:

resume in interface AudioPlayer

cancel

public void cancel()

Cancels currently playing audio.

Specified by:

cancel in interface AudioPlayer

reset

public void reset()

Prepares for another batch of output. Larger groups of output (such as all output associated with a single FreeTTSSpeakable) should be grouped between a reset/drain pair.

Specified by:

reset in interface AudioPlayer

close

public void close()

Closes this audio player

Specified by:

close in interface AudioPlayer

getVolume

public float getVolume()

Returns the current volume.

Specified by:

getVolume in interface AudioPlayer

Returns:

the current volume (between 0 and 1)

setVolume

public void setVolume(float volume)

Sets the current volume.

Specified by:

setVolume in interface AudioPlayer

Parameters:

volume - the current volume (between 0 and 1)

begin

public void begin(int size)

Starts the output of a set of data. For this JavaStreamingAudioPlayer, it actually opens the audio line. Since this is a streaming audio player, the size parameter has no meaning and effect at all, so any value can be used. Audio data for a single utterance should be grouped between begin/end pairs.

Specified by:

begin in interface AudioPlayer

Parameters:

size - supposedly the size of data between now and the end, but since this is a streaming audio player, this parameter has no meaning and effect at all

end

public boolean end()

Marks the end of a set of data. Audio data for a single utterance should be groupd between begin/end pairs.

Specified by:

end in interface AudioPlayer

Returns:

true if the audio was output properly, false if the output was cancelled or interrupted.

drain

public boolean drain()

Waits for all queued audio to be played

Specified by:

drain in interface AudioPlayer

Returns:

true if the audio played to completion, false if the audio was stopped [[[ WORKAROUND TODO The javax.sound.sampled drain is almost working properly. On linux, there is still a little bit of sound that needs to go out, even after drain is called. Thus, the drainDelay. We wait for a few hundred milliseconds while the data is really drained out of the system ]]]

getTime

public long getTime()

Gets the amount of played since the last mark

Specified by:

getTime in interface AudioPlayer

Returns:

the amount of audio in milliseconds

resetTime

public void resetTime()

Resets the audio clock

Specified by:

resetTime in interface AudioPlayer

write

public boolean write(byte[] audioData)

Writes the given bytes to the audio stream

Specified by:

write in interface AudioPlayer

Parameters:

audioData - audio data to write to the device

Returns:

true of the write completed successfully, false if the write was cancelled.

write

public boolean write(byte[] bytes,
                     int offset,
                     int size)

Writes the given bytes to the audio stream

Specified by:

write in interface AudioPlayer

Parameters:

bytes - audio data to write to the device

offset - the offset into the buffer

size - the size into the buffer

Returns:

true of the write completed successfully, false if the write was cancelled.

toString

public java.lang.String toString()

Returns the name of this audioplayer

Returns:

the name of the audio player

showMetrics

public void showMetrics()

Shows metrics for this audio player

Specified by:

showMetrics in interface AudioPlayer