Class AudioContext

java.lang.Object

com.codename1.media.audio.BaseAudioContext

com.codename1.media.audio.AudioContext

public final class AudioContext
extends BaseAudioContext

Renders an audio graph to the device's speaker in real time, the Web Audio AudioContext.

Not every platform has a real-time audio output; check isSupported() or test create() for null, and fall back to Media or SoundPool playback. OfflineAudioContext works everywhere.

AudioContext audio = AudioContext.create();
if (audio != null) {
    OscillatorNode osc = audio.createOscillator();
    GainNode amp = audio.createGain();
    osc.connect(amp).connect(audio.getDestination());
    double now = audio.getCurrentTime();
    amp.getGain().setValueAtTime(0, now).linearRampToValueAtTime(0.5f, now + 0.02)
            .setTargetAtTime(0, now + 0.1, 0.2);
    osc.start(now);
    osc.stop(now + 1.5);
}

The graph renders on the platform's audio thread. Callbacks such as AudioScheduledSourceNode.setOnEnded(Runnable) are delivered on the EDT.

Method Summary

Modifier and Type	Method	Description
void	close()	Releases the output for good.
static AudioContext	create()	Opens the default output at the device's preferred sample rate.
static AudioContext	create(int sampleRate)	Opens the default output.
double	getBaseLatency()	The processing latency the graph adds: one render quantum.
double	getOutputLatency()	The latency the platform reports between rendering and hearing a sample.
AudioContextState	getState()	The life cycle state.
static boolean	isSupported()	Whether this platform can play an audio graph in real time.
void	resume()	Resumes rendering after suspend().
void	suspend()	Pauses rendering; the clock stops.

Methods inherited from class BaseAudioContext

createAnalyser, createAudioProcessor, createAudioProcessor, createBiquadFilter, createBuffer, createBufferSource, createChannelMerger, createChannelMerger, createChannelSplitter, createChannelSplitter, createConstantSource, createConvolver, createDelay, createDelay, createDynamicsCompressor, createGain, createIIRFilter, createMicrophoneSource, createOscillator, createPanner, createPeriodicWave, createPeriodicWave, createStereoPanner, createWaveShaper, decodeAudioData, getCurrentTime, getDestination, getListener, getSampleRate, isAudioProcessorSupported, isHrtfSupported, isMicrophoneSourceSupported

Methods inherited from class Object

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

Method Details

isSupported

public static boolean isSupported()

Whether this platform can play an audio graph in real time.

Returns

true when create() can succeed

create

public static AudioContext create()

Opens the default output at the device's preferred sample rate.

Returns

a running context, or null when the platform has no real-time output

create

public static AudioContext create(int sampleRate)

Opens the default output.

Parameters

• sampleRate: the rate wanted, or 0 for the device's own; the device may run at another, which BaseAudioContext.getSampleRate() reports

Returns

a running context, or null when the platform has no real-time output

getState

public AudioContextState getState()

Description copied from class: BaseAudioContext

The life cycle state.

Returns

the state

Specified by:

getState in class BaseAudioContext

getBaseLatency

public double getBaseLatency()

The processing latency the graph adds: one render quantum.

Returns

seconds

getOutputLatency

public double getOutputLatency()

The latency the platform reports between rendering and hearing a sample.

Returns

seconds, or 0 when unknown

suspend

public void suspend()

Pauses rendering; the clock stops.

resume

public void resume()

Resumes rendering after suspend().

close

public void close()

Releases the output for good.