文件上傳框<input type="file">，除了可以選擇文件上傳之外，還可以調用攝像頭來拍攝照片或者視頻并上傳。capture屬性可以判斷前置or后置攝像頭。在視頻播放的過程中，用canvas定時截取一張圖片，然后用gif.js生成一張GIF圖，從而完成前端的視頻壓縮。
我這里使用的是Vue寫的，以下是我的流程及代碼：
一、下載gif.js相關文件，可以到這里下載，然后將這幾個文件放在根目錄的static/js里面。
gif.js相關文件及存放路徑
二、下載依賴包：
npm i timers
三、在頁面中聲明：
import { setInterval, clearInterval } from "timers";import GIF from "../../static/js/gif.js"四、html代碼塊：
<template> <div> <input ref="changeInput" type="file" accept="video/*" capture="user" @change="changeVideo" /> <div> <div>視頻大小：{{videoSize}}</div> <div>視頻時長：{{videoLength}}</div> <div> <video id="myvideo" :src="videoSrc" :width="winWidth" :height="winHeight" ref="videoId" autoplay="true" controls muted></video> <canvas id="canvas" :width="winWidth" :height="winHeight"></canvas> </div> </div> </div></template>五、在頁面加載完成時初始化GIF：
mounted(){ //初始gif this.gif = new GIF({ workers: 1, quality: 1000, width: window.innerWidth, height: window.innerHeight, workerScript: '../../static/js/gif.worker.js', }); },六、當input錄制完視頻返回頁面中，獲取到這個視頻文件，每次拿到視頻文件需要先移除之前的監聽：
//input文件走向 changeVideo(e){ var file = e.target.files[0]; const video = document.getElementById('myvideo'); //視頻開始播放 video.removeEventListener('play', this.videoPlay, false); //視頻播放完 video.removeEventListener('ended', this.videoEnded, false); this.androidFile(file); },七、上一步提到的this.androidFile方法，是通過這個視頻文件，在頁面播放一遍，在這個播放過程處理視頻，完成整個轉換過程，獲取到最終的文件：
//安卓拍攝視頻 androidFile(file){ //視頻字節大小 this.videoSize = file.size; const that = this; const video = document.getElementById('myvideo'); const canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); this.gifSetTime = true; this.gif.abort() this.gif.frames = []; //file轉base64 var reader = new FileReader(); reader.readAsDataURL(file); reader.onload = function () { that.videoSrc = this.result; video.play(); } //視頻開始播放 video.addEventListener('play', this.videoPlay, false); //視頻播放完 video.addEventListener('ended', this.videoEnded, false); //獲取到所有的圖片并渲染完后執行 this.gif.on('finished', function(blob) { if(that.fileAndroid.size == blob.size) return; console.log("gif的blob文件",blob); //file that.fileAndroid = that.convertBase64UrlToFile(blob); //上傳視頻文件 that.uploadVideo(that.fileAndroid); }); },八、步驟七所說的this.videoPlay方法。視頻在頁面播放過程中，每200毫秒通過canvas截取一張圖片，把這些圖片一張張給gif.js堆疊：
//視頻開始播放 videoPlay(){ const that = this; const video = document.getElementById('myvideo'); const canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); console.log("視頻時長",video.duration); this.videoLength = video.duration; //畫布上畫視頻，需要動態地獲取它，一幀一幀地畫出來 var times = setInterval(function(){ context.drawImage(video, 0, 0, that.winWidth, that.winHeight); that.gif.addFrame(context, { copy: true }); if(that.gifSetTime == false){ clearInterval(times); } }, 200); },九、步驟七所說的this.videoEnded方法。視頻播放完，通過gif.js將圖片堆疊的動態圖渲染出來：
//視頻播放完 videoEnded(){ this.gifSetTime = false; console.log("視頻播放完畢！") this.gif.render(); },十、步驟七所說的that.convertBase64UrlToFile方法。將gif.js生成的Blob文件轉換成File格式：
//blob to file convertBase64UrlToFile(blob) { var d = new Date().getTime(); var type = 'image/gif' return new File([blob],"fileGif-" + d + '.gif', {type:type}); },最后通過步驟七所說的that.uploadVideo方法，上傳圖片給服務器：
//上傳視頻 uploadVideo(file){ console.log("上傳的視頻文件", file) },在這提供我的全部代碼，Android的視頻文件比較大所以做壓縮，而IOS本身存在視頻壓縮，所以我這里做了區分
<template> <div> <input ref="changeInput" type="file" accept="video/*" capture="user" @change="changeVideo" /> <div> <div>視頻大小：{{videoSize}}</div> <div>視頻時長：{{videoLength}}</div> <div> <video id="myvideo" :src="videoSrc" :width="winWidth" :height="winHeight" ref="videoId" autoplay="true" controls muted></video> <canvas id="canvas" :width="winWidth" :height="winHeight"></canvas> </div> </div> </div></template><script>import { setInterval, clearInterval } from "timers";import GIF from "../../static/js/gif.js"export default { data(){ return { videoSize: '', videoSrc: '', videoLength: '', isAndroid: false, fileAndroid: {}, winWidth: window.innerWidth, winHeight: window.innerHeight, gifSetTime: false, gif: '', } }, created() { //判斷終端 var u = navigator.userAgent; var isAndroid = u.indexOf('Android') > -1 || u.indexOf('Adr') > -1; //android終端 var isiOS = !!u.match(//(i[^;]+;( U;)? CPU.+Mac OS X/); //ios終端 if(isAndroid){ console.log('isAndroid') this.isAndroid = true; }else if(isiOS){ console.log('isiOS') this.isAndroid = false; } }, mounted(){ //初始gif this.gif = new GIF({ workers: 1, quality: 1000, width: this.winWidth, height:this.winHeight, workerScript: '../../static/js/gif.worker.js', }); }, methods:{ //input文件走向 changeVideo(e){ var file = e.target.files[0]; const video = document.getElementById('myvideo'); if(file !== undefined){ //判斷走向 if(this.isAndroid){ //視頻開始播放 video.removeEventListener('play', this.videoPlay, false); //視頻播放完 video.removeEventListener('ended', this.videoEnded, false); this.androidFile(file); }else{ this.iphoneFile(file); } } }, //IOS拍攝視頻 iphoneFile(file){ const that = this; //視頻字節大小 this.videoSize = file.size; var url = null ; //file轉換成blob if (window.createObjectURL!=undefined) { // basic url = window.createObjectURL(file) ; } else if (window.URL!=undefined) { // mozilla(firefox) url = window.URL.createObjectURL(file) ; } else if (window.webkitURL!=undefined) { // webkit or chrome url = window.webkitURL.createObjectURL(file) ; } this.videoSrc = url; if(file.size < 2100000 && file.size > 500000){ this.uploadVideo(file); }else if(file.size >= 2100000){ this.$vux.toast.text('視頻太大，請限制在10秒內'); }else{ this.$vux.toast.text('視頻錄制不能少于5秒'); } }, //安卓拍攝視頻 androidFile(file){ //視頻字節大小 this.videoSize = file.size; const that = this; const video = document.getElementById('myvideo'); const canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); this.gifSetTime = true; this.gif.abort() this.gif.frames = []; //file轉base64 var reader = new FileReader(); reader.readAsDataURL(file); reader.onload = function () { that.videoSrc = this.result; video.play(); } //視頻開始播放 video.addEventListener('play', this.videoPlay, false); //視頻播放完 video.addEventListener('ended', this.videoEnded, false); this.gif.on('finished', function(blob) { if(that.fileAndroid.size == blob.size) return; console.log("gif的blob文件",blob); that.fileAndroid = that.convertBase64UrlToFile(blob); that.uploadVideo(that.fileAndroid); }); }, //視頻開始播放 videoPlay(){ const that = this; const video = document.getElementById('myvideo'); const canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); console.log("視頻時長",video.duration); this.videoLength = video.duration; //畫布上畫視頻，需要動態地獲取它，一幀一幀地畫出來 var times = setInterval(function(){ context.drawImage(video, 0, 0, that.winWidth, that.winHeight); that.gif.addFrame(context, { copy: true }); if(that.gifSetTime == false){ clearInterval(times); } }, 200); }, //視頻播放完 videoEnded(){ this.gifSetTime = false; console.log("視頻播放完畢！") this.gif.render(); }, //blob to file convertBase64UrlToFile(blob) { var d = new Date().getTime(); var type = 'image/gif' return new File([blob],"fileGif-" + d + '.gif', {type:type}); }, //上傳視頻 uploadVideo(file){ console.log("上傳的視頻文件", file) }, }};</script><style scoped></style>試過很多種方法，而這種在移動端瀏覽器（特別是微信瀏覽器！）的兼容性是最好的。但是這個生成的視頻文件將會失去音頻，如果需要音頻的可以看我另一篇簡書有說明幾種方法。有更好的方法歡迎大家留言，互相學習~
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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