本文实例讲述了js+HTML5基于过滤器从摄像头中捕获视频的方法。分享给大家供大家参考。具体如下：

index.html页面：

<div class="warning"><h2>Native web camera streaming (getUserMedia) is not supported in this browser.</h2></div><div class="container"> <h3>Current filter is: None</h3> <button>Click here to change video filter</button> <div style="clear:both"></div> <div class="col"> <h2>HTML5 &lt;video&gt; object</h2> <video></video> </div> <div class="col"> <h2>HTML5 &lt;canvas&gt; object</h2> <canvas width="600" height="450"></canvas> </div></div>

style.css文件：

.grayscale{ -webkit-filter:grayscale(1); -moz-filter:grayscale(1); -o-filter:grayscale(1); -ms-filter:grayscale(1); filter:grayscale(1);}.sepia{ -webkit-filter:sepia(0.8); -moz-filter:sepia(0.8); -o-filter:sepia(0.8); -ms-filter:sepia(0.8); filter:sepia(0.8);}.blur{ -webkit-filter:blur(3px); -moz-filter:blur(3px); -o-filter:blur(3px); -ms-filter:blur(3px); filter:blur(3px);}.brightness{ -webkit-filter:brightness(0.3); -moz-filter:brightness(0.3); -o-filter:brightness(0.3); -ms-filter:brightness(0.3); filter:brightness(0.3);}.contrast{ -webkit-filter:contrast(0.5); -moz-filter:contrast(0.5); -o-filter:contrast(0.5); -ms-filter:contrast(0.5); filter:contrast(0.5);}.hue-rotate{ -webkit-filter:hue-rotate(90deg); -moz-filter:hue-rotate(90deg); -o-filter:hue-rotate(90deg); -ms-filter:hue-rotate(90deg); filter:hue-rotate(90deg);}.hue-rotate2{ -webkit-filter:hue-rotate(180deg); -moz-filter:hue-rotate(180deg); -o-filter:hue-rotate(180deg); -ms-filter:hue-rotate(180deg); filter:hue-rotate(180deg);}.hue-rotate3{ -webkit-filter:hue-rotate(270deg); -moz-filter:hue-rotate(270deg); -o-filter:hue-rotate(270deg); -ms-filter:hue-rotate(270deg); filter:hue-rotate(270deg);}.saturate{ -webkit-filter:saturate(10); -moz-filter:saturate(10); -o-filter:saturate(10); -ms-filter:saturate(10); filter:saturate(10);}.invert{ -webkit-filter:invert(1); -moz-filter:invert(1); -o-filter: invert(1); -ms-filter: invert(1); filter: invert(1);}

script.js 文件：

// Main initializationdocument.addEventListener('DOMContentLoaded', function() { // Global variables var video = document.querySelector('video'); var audio, audioType; var canvas = document.querySelector('canvas'); var context = canvas.getContext('2d'); // Custom video filters var iFilter = 0; var filters = [ 'grayscale', 'sepia', 'blur', 'brightness', 'contrast', 'hue-rotate', 'hue-rotate2', 'hue-rotate3', 'saturate', 'invert', 'none' ]; // Get the video stream from the camera with getUserMedia navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia; window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL; if (navigator.getUserMedia) { // Evoke getUserMedia function navigator.getUserMedia({video: true, audio: true}, onSuccessCallback, onErrorCallback); function onSuccessCallback(stream) { // Use the stream from the camera as the source of the video element video.src = window.URL.createObjectURL(stream) || stream; // Autoplay video.play(); // HTML5 Audio audio = new Audio(); audioType = getAudioType(audio); if (audioType) { audio.src = 'polaroid.' + audioType; audio.play(); } } // Display an error function onErrorCallback(e) { var expl = 'An error occurred: [Reason: ' + e.code + ']'; console.error(expl); alert(expl); return; } } else { document.querySelector('.container').style.visibility = 'hidden'; document.querySelector('.warning').style.visibility = 'visible'; return; } // Draw the video stream at the canvas object function drawVideoAtCanvas(obj, context) { window.setInterval(function() { context.drawImage(obj, 0, 0); }, 60); } // The canPlayType() function doesn't return true or false. In recognition of how complex // formats are, the function returns a string: 'probably', 'maybe' or an empty string. 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; } // Add event listener for our video's Play function in order to produce video at the canvas video.addEventListener('play', function() { drawVideoAtCanvas(this, context); }, false); // Add event listener for our Button (to switch video filters) document.querySelector('button').addEventListener('click', function() { video.className = ''; canvas.className = ''; var effect = filters[iFilter++ % filters.length]; // Loop through the filters. if (effect) { video.classList.add(effect); canvas.classList.add(effect); document.querySelector('.container h3').innerHTML = 'Current filter is: ' + effect; } }, false);}, false);

希望本文所述对大家的javascript程序设计有所帮助。