Class AudioParam

java.lang.Object
com.codename1.media.audio.AudioParam
public final class AudioParam extends Object

A value of an AudioNode that can be scheduled ahead of time and modulated by other nodes, the Web Audio AudioParam.

The value at any moment is the automation timeline (or the default value when nothing is scheduled), plus the sum of every node output connected to the parameter with AudioNode.connect(AudioParam), clamped to getMinValue() and getMaxValue(). Scheduling methods return the parameter so calls can be chained:

OfflineAudioContext audio = new OfflineAudioContext(2, 44100, 44100);
GainNode gain = audio.createGain();
double now = audio.getCurrentTime();
gain.getGain().setValueAtTime(0, now)
        .linearRampToValueAtTime(1, now + 0.05)
        .setTargetAtTime(0.2f, now + 0.05, 0.1);

Times are in the context's time base, BaseAudioContext.getCurrentTime(). Every method may be called from any thread; changes reach the renderer at its next render quantum.

  • Method Details

    • getDefaultValue

      public float getDefaultValue()

      The value used when nothing is scheduled.

      Returns

      the default value

    • getMinValue

      public float getMinValue()

      The lowest value the parameter can take.

      Returns

      the nominal minimum

    • getMaxValue

      public float getMaxValue()

      The highest value the parameter can take.

      Returns

      the nominal maximum

    • getAutomationRate

      public AutomationRate getAutomationRate()

      The automation rate.

      Returns

      whether the value is computed per sample or per render quantum

    • setAutomationRate

      public void setAutomationRate(AutomationRate rate)

      Sets the automation rate.

      Parameters
      • rate: the new rate
      Throws
      • IllegalStateException: for a parameter whose rate the specification fixes, such as AudioBufferSourceNode.playbackRate

    • getValue

      public float getValue()

      The intrinsic value at the context's current time: the automation timeline, without the contribution of connected nodes.

      Returns

      the value

    • setValue

      public void setValue(float value)

      Sets the value now, the same as setValueAtTime(value, context.getCurrentTime()).

      Parameters
      • value: the new value

    • setValueAtTime

      public AudioParam setValueAtTime(float value, double startTime)

      Changes the value at startTime.

      Parameters

      • value: the new value

      • startTime: when, in context seconds

      Returns

      this parameter

    • linearRampToValueAtTime

      public AudioParam linearRampToValueAtTime(float value, double endTime)

      Ramps linearly from the previous scheduled value to value, reaching it at endTime.

      Parameters

      • value: the value to reach

      • endTime: when it is reached

      Returns

      this parameter

    • exponentialRampToValueAtTime

      public AudioParam exponentialRampToValueAtTime(float value, double endTime)

      Ramps exponentially from the previous scheduled value to value, reaching it at endTime. If the previous value is 0 or of the other sign the value holds until endTime, as the specification requires.

      Parameters

      • value: the value to reach; must not be 0

      • endTime: when it is reached

      Returns

      this parameter

    • setTargetAtTime

      public AudioParam setTargetAtTime(float target, double startTime, double timeConstant)

      Starts an exponential approach to target at startTime. After timeConstant seconds about 63% of the distance has been covered.

      Parameters

      • target: the value approached

      • startTime: when the approach starts

      • timeConstant: the time constant in seconds, 0 or more; 0 jumps

      Returns

      this parameter

    • setValueCurveAtTime

      public AudioParam setValueCurveAtTime(float[] values, double startTime, double duration)

      Follows values from startTime for duration seconds, linearly interpolating between them, then holds the last one.

      Parameters

      • values: at least two values; copied

      • startTime: when the curve starts

      • duration: how long it lasts, more than 0

      Returns

      this parameter

    • cancelScheduledValues

      public AudioParam cancelScheduledValues(double cancelTime)

      Removes every event scheduled at or after cancelTime.

      Parameters
      • cancelTime: the first time to clear
      Returns

      this parameter

    • cancelAndHoldAtTime

      public AudioParam cancelAndHoldAtTime(double cancelTime)

      Like cancelScheduledValues(double), but the value the timeline would have had at cancelTime is held from then on, so a ramp in progress stops where it was rather than jumping back.

      Parameters
      • cancelTime: when to hold
      Returns

      this parameter