Class DynamicsCompressorNode

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

Lowers the volume of loud passages so the mix stays clear of clipping: the Web Audio DynamicsCompressorNode.

Every parameter is k-rate. The detector follows the loudest channel, the gain curve has a soft knee getKnee() decibels wide centred on getThreshold(), and gain changes are smoothed by getAttack() and getRelease(). As in browsers the signal is delayed by a 6 ms look-ahead and a make-up gain raises the result so that a full-scale signal comes out near full scale. The specification leaves the exact curve to the implementation, so values match browsers in shape, not to the sample.

OfflineAudioContext audio = new OfflineAudioContext(2, 44100, 44100);
GainNode mix = audio.createGain();
DynamicsCompressorNode comp = audio.createDynamicsCompressor();
comp.getThreshold().setValue(-18);
comp.getRatio().setValue(4);
mix.connect(comp).connect(audio.getDestination());

  • Method Details

    • getThreshold

      public AudioParam getThreshold()

      The level, in dB, above which the signal is compressed; -24 by default.

      Returns

      the parameter

    • getKnee

      public AudioParam getKnee()

      The width of the soft knee in dB, 30 by default.

      Returns

      the parameter

    • getRatio

      public AudioParam getRatio()

      How many dB of input above the threshold make one dB of output, 12 by default.

      Returns

      the parameter

    • getAttack

      public AudioParam getAttack()

      How fast the gain falls when the signal gets louder: the time constant in seconds, 0.003 by default.

      Returns

      the parameter

    • getRelease

      public AudioParam getRelease()

      How fast the gain recovers when the signal gets quieter: the time constant in seconds, 0.25 by default.

      Returns

      the parameter

    • getReduction

      public float getReduction()

      The gain reduction currently applied, in dB: 0 or negative.

      Returns

      decibels