microsoft-cognitiveservices-speech-sdk
Version:
Microsoft Cognitive Services Speech SDK for JavaScript
137 lines (135 loc) • 5.96 kB
JavaScript
;
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.
Object.defineProperty(exports, "__esModule", { value: true });
exports.PcmRecorder = void 0;
const Exports_1 = require("../common/Exports");
class PcmRecorder {
constructor(stopInputOnRelease) {
this.privStopInputOnRelease = stopInputOnRelease;
}
record(context, mediaStream, outputStream) {
const desiredSampleRate = 16000;
const waveStreamEncoder = new Exports_1.RiffPcmEncoder(context.sampleRate, desiredSampleRate);
const micInput = context.createMediaStreamSource(mediaStream);
const attachScriptProcessor = () => {
// eslint-disable-next-line @typescript-eslint/explicit-function-return-type
const scriptNode = (() => {
let bufferSize = 0;
try {
return context.createScriptProcessor(bufferSize, 1, 1);
}
catch (error) {
// Webkit (<= version 31) requires a valid bufferSize.
bufferSize = 2048;
let audioSampleRate = context.sampleRate;
while (bufferSize < 16384 && audioSampleRate >= (2 * desiredSampleRate)) {
bufferSize <<= 1;
audioSampleRate >>= 1;
}
return context.createScriptProcessor(bufferSize, 1, 1);
}
})();
scriptNode.onaudioprocess = (event) => {
const inputFrame = event.inputBuffer.getChannelData(0);
if (outputStream && !outputStream.isClosed) {
const waveFrame = waveStreamEncoder.encode(inputFrame);
if (!!waveFrame) {
outputStream.writeStreamChunk({
buffer: waveFrame,
isEnd: false,
timeReceived: Date.now(),
});
}
}
};
micInput.connect(scriptNode);
scriptNode.connect(context.destination);
this.privMediaResources = {
scriptProcessorNode: scriptNode,
source: micInput,
stream: mediaStream,
};
};
// https://webaudio.github.io/web-audio-api/#audioworklet
// Using AudioWorklet to improve audio quality and avoid audio glitches due to blocking the UI thread
const skipAudioWorklet = !!this.privSpeechProcessorScript && this.privSpeechProcessorScript.toLowerCase() === "ignore";
if (!!context.audioWorklet && !skipAudioWorklet) {
if (!this.privSpeechProcessorScript) {
const workletScript = `class SP extends AudioWorkletProcessor {
constructor(options) {
super(options);
}
process(inputs, outputs) {
const input = inputs[0];
const output = [];
for (let channel = 0; channel < input.length; channel += 1) {
output[channel] = input[channel];
}
this.port.postMessage(output[0]);
return true;
}
}
registerProcessor('speech-processor', SP);`;
const blob = new Blob([workletScript], { type: "application/javascript; charset=utf-8" });
this.privSpeechProcessorScript = URL.createObjectURL(blob);
}
context.audioWorklet
.addModule(this.privSpeechProcessorScript)
.then(() => {
const workletNode = new AudioWorkletNode(context, "speech-processor");
workletNode.port.onmessage = (ev) => {
const inputFrame = ev.data;
if (outputStream && !outputStream.isClosed) {
const waveFrame = waveStreamEncoder.encode(inputFrame);
if (!!waveFrame) {
outputStream.writeStreamChunk({
buffer: waveFrame,
isEnd: false,
timeReceived: Date.now(),
});
}
}
};
micInput.connect(workletNode);
workletNode.connect(context.destination);
this.privMediaResources = {
scriptProcessorNode: workletNode,
source: micInput,
stream: mediaStream,
};
})
.catch(() => {
attachScriptProcessor();
});
}
else {
try {
attachScriptProcessor();
}
catch (err) {
throw new Error(`Unable to start audio worklet node for PCMRecorder: ${err}`);
}
}
}
releaseMediaResources(context) {
if (this.privMediaResources) {
if (this.privMediaResources.scriptProcessorNode) {
this.privMediaResources.scriptProcessorNode.disconnect(context.destination);
this.privMediaResources.scriptProcessorNode = null;
}
if (this.privMediaResources.source) {
this.privMediaResources.source.disconnect();
if (this.privStopInputOnRelease) {
this.privMediaResources.stream.getTracks().forEach((track) => track.stop());
}
this.privMediaResources.source = null;
}
}
}
setWorkletUrl(url) {
this.privSpeechProcessorScript = url;
}
}
exports.PcmRecorder = PcmRecorder;
//# sourceMappingURL=PCMRecorder.js.map