processor.js

import Module from "./compiled_processor_perf.js";
import { RENDER_QUANTUM_FRAMES, MAX_CHANNEL_COUNT, HeapAudioBuffer }
    from './lib/wasm-audio-helper.js';


class SimpleProcessor extends AudioWorkletProcessor {
    constructor() {
        super();

        this._heapInputBuffer = new HeapAudioBuffer(Module, RENDER_QUANTUM_FRAMES,
            2, MAX_CHANNEL_COUNT);
        this._heapOutputBuffer = new HeapAudioBuffer(Module, RENDER_QUANTUM_FRAMES,
            2, MAX_CHANNEL_COUNT);
        this._processPerf = new Module.ProcessorPerf();
    }

    /**
 * @param {Float32Array[][]} inputs
 * @param {Float32Array[][]} outputs
 * @param {Record<string, Float32Array>} parameters
 */
    process(inputs, outputs, parameters) {
        // Use the 1st input and output only to make the example simpler. |input|
        // and |output| here have the similar structure with the AudioBuffer
        // interface. (i.e. An array of Float32Array)
        let input = inputs[0];
        let output = outputs[0];
        const bufferSize = outputs[0][0].length;

        // For this given render quantum, the channel count of the node is fixed
        // and identical for the input and the output.
        let channelCount = input.length;

        // Prepare HeapAudioBuffer for the channel count change in the current
        // render quantum.
        this._heapInputBuffer.adaptChannel(channelCount);
        this._heapOutputBuffer.adaptChannel(channelCount);

        // Copy-in, process and copy-out.
        for (let channel = 0; channel < channelCount; ++channel) {
            this._heapInputBuffer.getChannelData(channel).set(input[channel]);
        }
        this._processPerf.processPerf(this._heapInputBuffer.getHeapAddress(),
            this._heapOutputBuffer.getHeapAddress(),
            channelCount);
        for (let channel = 0; channel < channelCount; ++channel) {
            output[channel].set(this._heapOutputBuffer.getChannelData(channel));
        }
        return true;
    }
}

registerProcessor("simple-processor", SimpleProcessor);