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：
Native web camera streaming (getUserMedia) is not supported in this browser.
Current filter is: None
HTML5
HTML5
style.css文件：
script.js 文件：
dio,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);
},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。
