webrtc打开默认摄像头
程序员文章站
2022-07-01 15:35:00
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1.main.js
核心代码：
const stream = await navigator.mediaDevices.getUserMedia(constraints);/*
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree.
*/
'use strict';
// Put variables in global scope to make them available to the browser console.
const constraints = window.constraints = {
audio: false,
video: true
};
function handleSuccess(stream) {
const video = document.querySelector('video');
const videoTracks = stream.getVideoTracks();
console.log('Got stream with constraints:', constraints);
console.log(`Using video device: ${videoTracks[0].label}`);
//window.stream = stream; // make variable available to browser console
video.srcObject = stream;
}
function handleError(error) {
if (error.name === 'ConstraintNotSatisfiedError') {
let v = constraints.video;
errorMsg(`The resolution ${v.width.exact}x${v.height.exact} px is not supported by your device.`);
} else if (error.name === 'PermissionDeniedError') {
errorMsg('Permissions have not been granted to use your camera and ' +
'microphone, you need to allow the page access to your devices in ' +
'order for the demo to work.');
}
errorMsg(`getUserMedia error: ${error.name}`, error);
}
function errorMsg(msg, error) {
const errorElement = document.querySelector('#errorMsg');
errorElement.innerHTML += `<p>${msg}</p>`;
if (typeof error !== 'undefined') {
console.error(error);
}
}
async function init(e) {
try {
const stream = await navigator.mediaDevices.getUserMedia(constraints);
handleSuccess(stream);
e.target.disabled = true;
} catch (e) {
handleError(e);
}
}
document.querySelector('#showVideo').addEventListener('click', e => init(e));2.index.html
<!DOCTYPE html>
<!--
* Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree.
-->
<html>
<head>
<meta charset="utf-8">
<meta name="description" content="WebRTC code samples">
<meta name="viewport" content="width=device-width, user-scalable=yes, initial-scale=1, maximum-scale=1">
<meta itemprop="description" content="Client-side WebRTC code samples">
<meta itemprop="image" content="../../../images/webrtc-icon-192x192.png">
<meta itemprop="name" content="WebRTC code samples">
<meta name="mobile-web-app-capable" content="yes">
<meta id="theme-color" name="theme-color" content="#ffffff">
<base target="_blank">
<title>getUserMedia</title>
<link rel="icon" sizes="192x192" href="../../../images/webrtc-icon-192x192.png">
<link href="//fonts.googleapis.com/css?family=Roboto:300,400,500,700" rel="stylesheet" type="text/css">
<link rel="stylesheet" href="../../../css/main.css">
</head>
<body>
<div id="container">
<h1><a href="//webrtc.github.io/samples/" title="WebRTC samples homepage">WebRTC samples</a>
<span>getUserMedia</span></h1>
<video id="gum-local" autoplay playsinline></video>
<button id="showVideo">Open camera</button>
<div id="errorMsg"></div>
<p class="warning"><strong>Warning:</strong> if you're not using headphones, pressing play will cause feedback.</p>
<p>Display the video stream from <code>getUserMedia()</code> in a video element.</p>
<p>The <code>MediaStream</code> object <code>stream</code> passed to the <code>getUserMedia()</code> callback is in
global scope, so you can inspect it from the console.</p>
<a href="https://github.com/webrtc/samples/tree/gh-pages/src/content/getusermedia/gum"
title="View source for this page on GitHub" id="viewSource">View source on GitHub</a>
</div>
<script src="https://webrtc.github.io/adapter/adapter-latest.js"></script>
<script src="js/main.js"></script>
<script src="../../../js/lib/ga.js"></script>
</body>
</html>