François Beaufort
ウェブ プラットフォームで Media Capture と Streams API を使用すると、ユーザーのカメラとマイクにアクセスできます。getUserMedia() メソッドは、メディア ストリームとしてキャプチャするためにカメラやマイクにアクセスするようユーザーに求めます。このストリームは、非常に低いレイテンシの音声処理を行う AudioWorklet を使用して、別のウェブ オーディオ スレッドで処理できます。
次の例は、ユーザーのマイクからの音声を効率的に処理する方法を示しています。
let stream;
startMicrophoneButton.addEventListener("click", async () => {
// Prompt the user to use their microphone.
stream = await navigator.mediaDevices.getUserMedia({
audio: true,
});
const context = new AudioContext();
const source = context.createMediaStreamSource(stream);
// Load and execute the module script.
await context.audioWorklet.addModule("processor.js");
// Create an AudioWorkletNode. The name of the processor is the
// one passed to registerProcessor() in the module script.
const processor = new AudioWorkletNode(context, "processor");
source.connect(processor).connect(context.destination);
log("Your microphone audio is being used.");
});
stopMicrophoneButton.addEventListener("click", () => {
// Stop the stream.
stream.getTracks().forEach(track => track.stop());
log("Your microphone audio is not used anymore.");
});
// processor.js
// This file is evaluated in the audio rendering thread
// upon context.audioWorklet.addModule() call.
class Processor extends AudioWorkletProcessor {
process([input], [output]) {
// Copy inputs to outputs.
output[0].set(input[0]);
return true;
}
}
registerProcessor("processor", Processor);
ブラウザ サポート
MediaDevices.getUserMedia()
ウェブ オーディオ
AudioWorklet
関連情報
デモ
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link
rel="icon"
href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🎙️</text></svg>"
/>
<title>How to process audio from the user's microphone</title>
</head>
<body>
<h1>How to process audio from the user's microphone</h1>
<button id="startMicrophoneButton">Start using microphone</button>
<button id="stopMicrophoneButton" disabled>Stop using microphone</button>
<pre id="logs"></pre>
</body>
</html>CSS
:root {
color-scheme: dark light;
}
html {
box-sizing: border-box;
}
*,
*:before,
*:after {
box-sizing: inherit;
}
body {
margin: 1rem;
font-family: system-ui, sans-serif;
}
button {
display: block;
margin-bottom: 4px;
}
pre {
color: red;
white-space: pre-line;
}
JS
const startMicrophoneButton = document.querySelector('#startMicrophoneButton');
const stopMicrophoneButton = document.querySelector('#stopMicrophoneButton');
let stream;
startMicrophoneButton.addEventListener("click", async () => {
// Prompt the user to use their microphone.
stream = await navigator.mediaDevices.getUserMedia({
audio: true,
});
const context = new AudioContext();
const source = context.createMediaStreamSource(stream);
// Load and execute the module script.
await context.audioWorklet.addModule("processor.js");
// Create an AudioWorkletNode. The name of the processor is the
// one passed to registerProcessor() in the module script.
const processor = new AudioWorkletNode(context, "processor");
source.connect(processor).connect(context.destination);
stopMicrophoneButton.disabled = false;
log("Your microphone audio is being used.");
});
stopMicrophoneButton.addEventListener("click", () => {
// Stop the stream.
stream.getTracks().forEach(track => track.stop());
log("Your microphone audio is not used anymore.");
});