@mohayonao/script-processor-rack v0.1.0

SCRIPT PROCESSOR RACK

ScriptProcessorRackNode for Web Audio API

Installation

Node.js

npm install @mohayonao/script-processor-rack

Example

import ScriptProcessorRack from "@mohayonao/script-processor-rack";
import fetchAudioBuffer from "@mohayonao/web-audio-utils/fetchAudioBuffer";
import Reduction from "./Reduction";

class OnePole {
  constructor(coef, bufferSize) {
    this.output = new Float32Array(bufferSize);
    this.b1 = coef;
    this.y1 = 0;
  }

  process(input) {
    let output = this.output;
    let y0, y1 = this.y1, b1 = this.b1;

    if (b1 >= 0) {
      for (let i = 0, imax = input.length; i < imax; ++i) {
        y0 = input[i];
        output[i] = y1 = y0 + b1 * (y1 - y0);
      }
    } else {
      for (let i = 0, imax = input.length; i < imax; ++i) {
        y0 = input[i];
        output[i] = y1 = y0 + b1 * (y1 + y0);
      }
    }

    this.y1 = y1;

    return output;
  }
}

let audioContext = new AudioContext();
let bufferSource = audioContext.createBufferSource();
let effector = new ScriptProcessorRack(audioContext, 512);

fetchAudioBuffer("./amen.wav", audioContext).then((audioBuffer) => {
  bufferSource.buffer = audioBuffer;
  bufferSource.start();

  effector.addProcessor(new OnePole(0.95, effector.bufferSize)::process);
  effector.addProcessor(new Reduction(0.8, effector.bufferSize)::process);

  bufferSource.connect(effector);
  effector.connect(audioContext.destination);

  setTimeout(() => {
    bufferSource.stop();
    bufferSource.disconnect();
    effector.disconnect();
  }, 1000);  
})

API

• constructor(audioContext: AudioContext, [ bufferSize: number ]): ScriptProcessorNode

Instance attributes

• context: AudioContext readonly
• bufferSize: number readonly

Instance methods

• addProcessor(func: function): void
• removeProcessor(func: function): void
• connect(...args): void
• disconnect(...args): void
• dispose(): void

License

MIT