É possível acessar a câmera e o microfone do usuário na plataforma da Web com a API Media Capture e Streams. O método getUserMedia()
solicita que o usuário acesse uma câmera e/ou microfone para capturar como um stream de mídia. Esse stream pode ser processado em uma linha de execução separada de Áudio da Web com um AudioWorklet, que fornece processamento de áudio com latência muito baixa.
O exemplo abaixo mostra como processar áudio do microfone do usuário para melhorar o desempenho.
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);
Suporte ao navegador
MediaDevices.getUserMedia()
Áudio da Web
AudioWorklet
Leia mais
- Especificação de captura de mídia e streams do W3C
- Especificação de áudio da Web do W3C
- Entrar no AudioWorklet
Demonstração
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.");
});