uk.org.toot.audio.server
Class TimedAudioServer

java.lang.Object
  uk.org.toot.audio.server.AbstractAudioServer
      uk.org.toot.audio.server.TimedAudioServer

All Implemented Interfaces:

java.lang.Runnable, uk.org.toot.audio.server.AudioServer, ExtendedAudioServer

Direct Known Subclasses:

PriorityAudioServer

public abstract class TimedAudioServer
extends AbstractAudioServer
implements java.lang.Runnable, ExtendedAudioServer

TimedAudioServer extends AbstractAudioServer to control the timing of an AudioClient. The buffer size, latency and timing strategy may be varied while running. Note that changing latency may cause inputs to glitch.

Field Summary

protected boolean	hasStopped
protected boolean	isRunning
protected float	maximumLatencyMilliseconds
protected int	stableCount
protected int	stableThreshold
protected boolean	started
protected AudioSyncLine	syncLine

Fields inherited from class uk.org.toot.audio.server.AbstractAudioServer

bufferFrames, endTimeNanos, startTimeNanos

Fields inherited from interface uk.org.toot.audio.server.AudioServer

THREAD_NAME

Constructor Summary

TimedAudioServer()

Method Summary

protected int	calculateBufferFrames()
protected boolean	canStart()
protected void	controlGained() Called when the control loop gains control.
float	getActualLatencyMilliseconds() Return the actual instantaneous software output latency in milliseconds.
float	getBufferMilliseconds() Return the duration of the buffers in milliseconds.
int	getBufferUnderRuns() Return the number of buffer underruns which may have resulted in an audio glitch.
float	getLatencyMilliseconds() Return the requested software output latency in milliseconds.
float	getLowestLatencyMilliseconds() Because latency is measured just after writing a buffer and represents the maximum latency, the lowest latency has to be compensated by the duration of the buffer.
float	getMaximumLatencyMilliseconds() Return the maximum software output latency which may be requested.
float	getMinimumLatencyMilliseconds() Return the minimum software output latency which may be requested.
int	getTotalLatencyFrames() Return the total latency from analogue input to analogue output.
boolean	isRunning()
protected void	reset()
void	resetMetrics(boolean resetUnderruns)
void	run()
void	setBufferMilliseconds(float ms) Set the duration of the buffers in milliseconds.
void	setLatencyMilliseconds(float ms) Set the software output latency request in milliseconds.
protected void	startImpl()
protected void	stopImpl()
protected void	sync() Called synchronously with the server to simplify concurrency issues.

Methods inherited from class uk.org.toot.audio.server.AbstractAudioServer

_createAudioBuffer, checkStart, createAudioBuffer, getBufferFrames, getLoad, removeAudioBuffer, resizeBuffers, setClient, start, stop, work

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.org.toot.audio.server.ExtendedAudioServer

getConfigKey, getInputs, getOutputs, getSampleSizeInBits

Methods inherited from interface uk.org.toot.audio.server.AudioServer

closeAudioInput, closeAudioOutput, createAudioBuffer, getAvailableInputNames, getAvailableOutputNames, getInputLatencyFrames, getLoad, getOutputLatencyFrames, getSampleRate, openAudioInput, openAudioOutput, setClient, start, stop

Field Detail

isRunning

protected boolean isRunning

hasStopped

protected boolean hasStopped

maximumLatencyMilliseconds

protected float maximumLatencyMilliseconds

syncLine

protected AudioSyncLine syncLine

started

protected boolean started

stableCount

protected int stableCount

stableThreshold

protected int stableThreshold

Constructor Detail

TimedAudioServer

public TimedAudioServer()

Method Detail

canStart

protected boolean canStart()

Overrides:

canStart in class AbstractAudioServer

startImpl

protected void startImpl()

Specified by:

startImpl in class AbstractAudioServer

stopImpl

protected void stopImpl()

Specified by:

stopImpl in class AbstractAudioServer

isRunning

public boolean isRunning()

Specified by:

isRunning in interface uk.org.toot.audio.server.AudioServer

getTotalLatencyFrames

public int getTotalLatencyFrames()

Return the total latency from analogue input to analogue output.

Specified by:

getTotalLatencyFrames in interface uk.org.toot.audio.server.AudioServer

run

public void run()

Specified by:

run in interface java.lang.Runnable

sync

protected void sync()

Called synchronously with the server to simplify concurrency issues.

controlGained

protected void controlGained()

Called when the control loop gains control.

resetMetrics

public void resetMetrics(boolean resetUnderruns)

Specified by:

resetMetrics in interface ExtendedAudioServer

reset

protected void reset()

setLatencyMilliseconds

public void setLatencyMilliseconds(float ms)

Set the software output latency request in milliseconds. This is the demand to the control loop.

Specified by:

setLatencyMilliseconds in interface ExtendedAudioServer

getLatencyMilliseconds

public float getLatencyMilliseconds()

Return the requested software output latency in milliseconds.

Specified by:

getLatencyMilliseconds in interface ExtendedAudioServer

getActualLatencyMilliseconds

public float getActualLatencyMilliseconds()

Return the actual instantaneous software output latency in milliseconds. This is the controlled amount which will diverge from the requested amount due to instantaneous control error caused by timing jitter.

Specified by:

getActualLatencyMilliseconds in interface ExtendedAudioServer

getLowestLatencyMilliseconds

public float getLowestLatencyMilliseconds()

Because latency is measured just after writing a buffer and represents the maximum latency, the lowest latency has to be compensated by the duration of the buffer. This might not be the best place to do the compensation but it is the cheapest. While bufferMilliseconds is effectively immutable it's ok.

Specified by:

getLowestLatencyMilliseconds in interface ExtendedAudioServer

getMinimumLatencyMilliseconds

public float getMinimumLatencyMilliseconds()

Return the minimum software output latency which may be requested.

Specified by:

getMinimumLatencyMilliseconds in interface ExtendedAudioServer

getMaximumLatencyMilliseconds

public float getMaximumLatencyMilliseconds()

Return the maximum software output latency which may be requested.

Specified by:

getMaximumLatencyMilliseconds in interface ExtendedAudioServer

getBufferUnderRuns

public int getBufferUnderRuns()

Return the number of buffer underruns which may have resulted in an audio glitch.

Specified by:

getBufferUnderRuns in interface ExtendedAudioServer

calculateBufferFrames

protected int calculateBufferFrames()

getBufferMilliseconds

public float getBufferMilliseconds()

Return the duration of the buffers in milliseconds.

Specified by:

getBufferMilliseconds in interface ExtendedAudioServer

setBufferMilliseconds

public void setBufferMilliseconds(float ms)

Set the duration of the buffers in milliseconds.

Specified by:

setBufferMilliseconds in interface ExtendedAudioServer