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ES5 AudioWorklet Processor
function RecorderProcessor(options) {
AudioWorkletProcessor.call(this);
var processorOptions = options.processorOptions || {};
this.numInputChannels = processorOptions.numInputChannels || 2;
this.recording = false;
this.clear();
this.port.onmessage = function(event) {
var data = event.data;
if (data.name === 'start') {
this.record(data.duration);
} else if (data.name === 'stop') {
this.stop();
}
}.bind(this);
}
RecorderProcessor.prototype = Object.create(AudioWorkletProcessor.prototype);
RecorderProcessor.prototype.constructor = RecorderProcessor;
RecorderProcessor.prototype.process = function(inputs, outputs) {
if (!this.recording) {
return true;
} else if (this.sampleLimit && this.recordedSamples >= this.sampleLimit) {
this.stop();
}
var input = inputs[0];
var output = outputs[0];
for (var channel = 0; channel < output.length; ++channel) {
var inputChannel = input[channel];
if (channel === 0) {
this.leftBuffers.push(inputChannel);
if (this.numInputChannels === 1) {
this.rightBuffers.push(inputChannel);
}
} else if (channel === 1 && this.numInputChannels > 1) {
this.rightBuffers.push(inputChannel);
}
}
this.recordedSamples += output[0].length;
return true;
};
RecorderProcessor.prototype.record = function(duration) {
if (duration) {
this.sampleLimit = Math.round(duration * sampleRate);
}
this.recording = true;
};
RecorderProcessor.prototype.stop = function() {
this.recording = false;
const buffers = this.getBuffers();
const leftBuffer = buffers[0].buffer;
const rightBuffer = buffers[1].buffer;
this.port.postMessage(
{
name: 'buffers',
leftBuffer: leftBuffer,
rightBuffer: rightBuffer
},
[leftBuffer, rightBuffer]
);
this.clear();
};
RecorderProcessor.prototype.getBuffers = function() {
var buffers = [];
buffers.push(this.mergeBuffers(this.leftBuffers));
buffers.push(this.mergeBuffers(this.rightBuffers));
return buffers;
};
RecorderProcessor.prototype.mergeBuffers = function(channelBuffer) {
var result = new Float32Array(this.recordedSamples);
var offset = 0;
var lng = channelBuffer.length;
for (var i = 0; i < lng; i++) {
var buffer = channelBuffer[i];
result.set(buffer, offset);
offset += buffer.length;
}
return result;
};
RecorderProcessor.prototype.clear = function() {
this.leftBuffers = [];
this.rightBuffers = [];
this.recordedSamples = 0;
this.sampleLimit = null;
};
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