52 lines
2.3 KiB
JavaScript
52 lines
2.3 KiB
JavaScript
class OwrxAudioProcessor extends AudioWorkletProcessor {
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constructor(options){
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super(options);
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// initialize ringbuffer, make sure it aligns with the expected buffer size of 128
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this.bufferSize = Math.round(options.processorOptions.maxBufferSize / 128) * 128;
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this.audioBuffer = new Float32Array(this.bufferSize);
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this.inPos = 0;
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this.outPos = 0;
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this.port.addEventListener('message', (m) => {
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if (typeof(m.data) === 'string') {
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const json = JSON.parse(m.data);
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if (json.cmd && json.cmd === 'getBuffers') {
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this.reportBuffers();
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}
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} else {
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// the ringbuffer size is aligned to the output buffer size, which means that the input buffers might
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// need to wrap around the end of the ringbuffer, back to the start.
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// it is better to have this processing here instead of in the time-critical process function.
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if (this.inPos + m.data.length <= this.bufferSize) {
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// we have enough space, so just copy data over.
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this.audioBuffer.set(m.data, this.inPos);
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} else {
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// we don't have enough space, so we need to split the data.
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const remaining = this.bufferSize - this.inPos;
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this.audioBuffer.set(m.data.subarray(0, remaining), this.inPos);
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this.audioBuffer.set(m.data.subarray(remaining));
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}
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this.inPos = (this.inPos + m.data.length) % this.bufferSize;
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}
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});
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this.port.addEventListener('messageerror', console.error);
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this.port.start();
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}
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process(inputs, outputs) {
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if (this.remaining() < 128) return true;
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outputs[0].forEach((output) => {
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output.set(this.audioBuffer.subarray(this.outPos, this.outPos + 128));
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});
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this.outPos = (this.outPos + 128) % this.bufferSize;
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return true;
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}
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remaining() {
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const mod = (this.inPos - this.outPos) % this.bufferSize;
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if (mod >= 0) return mod;
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return mod + this.bufferSize;
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}
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reportBuffers() {
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this.port.postMessage(JSON.stringify({buffersize: this.remaining()}));
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}
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}
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registerProcessor('openwebrx-audio-processor', OwrxAudioProcessor); |