• [转] HTML5利用WebRTC的getUserMedia获取摄像头信息模拟拍照及视频(完整示例)


    <!DOCTYPE html>
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    <title>HTML5 GetUserMedia Demo</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0" />
    </head>
    <body>
    <input type="button" title="开启摄像头" value="开启摄像头" onclick="getMedia();" /><br />
    <video height="120px" autoplay="autoplay"></video><hr />
    <input type="button" title="拍照" value="拍照" onclick="getPhoto();" /><br />
    <canvas id="canvas1" height="120px" ></canvas><hr />
    <input type="button" title="视频" value="视频" onclick="getVedio();" /><br />
    <canvas id="canvas2" height="120px"></canvas>
    
    <script type="text/javascript">
    var video = document.querySelector('video');
    var audio, audioType;
    
    var canvas1 = document.getElementById('canvas1');
    var context1 = canvas1.getContext('2d');
    
    var canvas2 = document.getElementById('canvas2');
    var context2 = canvas2.getContext('2d');
    
    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
    window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;
    
    var exArray = []; //存储设备源ID
    MediaStreamTrack.getSources(function (sourceInfos) {
    for (var i = 0; i != sourceInfos.length; ++i) {
    var sourceInfo = sourceInfos[i];
    //这里会遍历audio,video,所以要加以区分
    if (sourceInfo.kind === 'video') {
    exArray.push(sourceInfo.id);
    }
    }
    });
    
    function getMedia() {
    if (navigator.getUserMedia) {
    navigator.getUserMedia({
    'video': {
    'optional': [{
    'sourceId': exArray[1] //0为前置摄像头,1为后置
    }]
    },
    'audio':true
    }, successFunc, errorFunc); //success是获取成功的回调函数
    }
    else {
    alert('Native device media streaming (getUserMedia) not supported in this browser.');
    }
    }
    
    function successFunc(stream) {
    //alert('Succeed to get media!');
    if (video.mozSrcObject !== undefined) {
    //Firefox中,video.mozSrcObject最初为null,而不是未定义的,我们可以靠这个来检测Firefox的支持
    video.mozSrcObject = stream;
    }
    else {
    video.src = window.URL && window.URL.createObjectURL(stream) || stream;
    }
    
    //video.play();
    
    // 音频
    audio = new Audio();
    audioType = getAudioType(audio);
    if (audioType) {
    audio.src = 'polaroid.' + audioType;
    audio.play();
    }
    }
    function errorFunc(e) {
    alert('Error!'+e);
    }
    
    
    // 将视频帧绘制到Canvas对象上,Canvas每60ms切换帧,形成肉眼视频效果
    function drawVideoAtCanvas(video,context) {
    window.setInterval(function () {
    context.drawImage(video, 0, 0,90,120);
    }, 60);
    }
    
    //获取音频格式
    function getAudioType(element) {
    if (element.canPlayType) {
    if (element.canPlayType('audio/mp4; codecs="mp4a.40.5"') !== '') {
    return ('aac');
    } else if (element.canPlayType('audio/ogg; codecs="vorbis"') !== '') {
    return ("ogg");
    }
    }
    return false;
    }
    
    // vedio播放时触发,绘制vedio帧图像到canvas
    // video.addEventListener('play', function () {
    // drawVideoAtCanvas(video, context2);
    // }, false);
    
    //拍照
    function getPhoto() {
    context1.drawImage(video, 0, 0,90,120); //将video对象内指定的区域捕捉绘制到画布上指定的区域,实现拍照。
    }
    
    //视频
    function getVedio() {
    drawVideoAtCanvas(video, context2);
    }
    
    </script>
    </body>
    </html>

    在安卓的Chrome(版本Beta 39.0.2171.44)上测试的效果截图:

    现在遇到一个问题:如何实现视频录制效果,也就是以视频文件保存到本地?

    将Canvas获取的所有的帧图像组织起来,通过算法转换?

    如果高见,望赐教!

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  • 原文地址:https://www.cnblogs.com/chris-oil/p/8305729.html
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