基于fastadmin框架，上传视频，自动截取视频封面图

基于fastadmin框架，上传视频，自动截取视频封面图

最近用fastadmin开发了一个项目，需要用到视频的封面图片，客户又不能一一提供视频对应的封面，为减少工作量，需要在后台上传视频后直接生成默认封面图片，也可以自动上传想要的封面图片；
利用fastadmin框架，生成视频上传功能，在此基础上添加功能。

首先是页面，放的是add页面，edit页面是一样的

此处是手动上传的封面图
<div class="form-group"><label class="control-label col-xs-12 col-sm-2">{:__('Head_image')}:</label><div class="col-xs-12 col-sm-8"><div class="input-group"><input id="c-head_image"  class="form-control" size="50" name="row[head_image]" type="text"><div class="input-group-addon no-border no-padding"><span><button type="button" id="plupload-head_image" class="btn btn-danger plupload" data-input-id="c-head_image" data-mimetype="image/gif,image/jpeg,image/png,image/jpg,image/bmp" data-multiple="false" data-preview-id="p-head_image"><i class="fa fa-upload"></i> {:__('Upload')}</button></span><span><button type="button" id="fachoose-head_image" class="btn btn-primary fachoose" data-input-id="c-head_image" data-mimetype="image/*" data-multiple="false"><i class="fa fa-list"></i> {:__('Choose')}</button></span></div><span class="msg-box n-right" for="c-head_image"></span></div><ul class="row list-inline plupload-preview" id="p-head_image"></ul></div><div class="col-sm-10 col-sm-offset-2 col-xs-12" style="color: red;">封面图272*272，小于50kb</div>
</div>此处是上传视频
<div class="form-group"><label class="control-label col-xs-12 col-sm-2">{:__('Video_file')}:</label><div class="col-xs-12 col-sm-8"><div class="input-group"><input id="c-video_file" class="form-control" size="5000" name="row[video_file]" type="text"><div class="input-group-addon no-border no-padding"><span><button type="button" id="plupload-video_file" class="btn btn-danger plupload" data-mimetype="video/mp4" data-input-id="c-video_file" data-multiple="false" data-preview-id="p-video_file"><i class="fa fa-upload"></i> {:__('Upload')}</button></span></div><span class="msg-box n-right" for="c-video_file"></span></div><!--<ul class="row list-inline plupload-preview" id="p-video_file"></ul>--><video id="video" style="width: 160px;height:120px; " ></video></div><div class="col-sm-10 col-sm-offset-2 col-xs-12" style="color: red;">时长不超过15s，mp4格式，小于1M</div>
</div>此处是上传视频后自动生成的默认封面图
<div class="form-group"><label class="control-label col-xs-12 col-sm-2">{:__('默认封面图')}:</label><div class="col-xs-12 col-sm-8"><input id="fengmianinput" class="form-control" type="hidden" name="row[moren_image]"><img style="width: 160px;height:120px; " id="fengmian" src="" alt=""></div><div class="col-sm-10 col-sm-offset-2 col-xs-12" style="color: red;">上传视频后自动生成</div>
</div>

这一部分只要根据平时框架自动生成就可以了，最主要的是js文件中添加方法，下面放上最主要的js部分代码

//add方法内添加
add: function () {$("#plupload-video_file").data('upload-success',function(res){ //视频上传成功后触发//console.log(res);$("#video").attr('src',res.url);});var video = document.getElementById('video');var canvas = document.createElement('canvas');var ctx = canvas.getContext('2d');width = video.clientWidth;height = video.clientHeight;video.addEventListener('loadeddata', function (e) {// console.log('loadeddata')this.currentTime=1.5;canvas.width = this.videoWidth;canvas.height = this.videoHeight;width = this.videoWidth;height = this.videoHeight;// console.log(width, height)// console.log(this)var currentTime = this.currentTime;var that=this;setTimeout(function(){  //此处的setTimeout方法，是为了防止截取到视频前几帧为黑屏，如果可以确保视频没有黑屏，可以不用setTimeout方法ctx.drawImage(that, 0, 0, width, height);var src = canvas.toDataURL('image/jpeg');console.log(src);$("#fengmianinput").attr('value',src);$("#fengmian").attr('src',src);},200);});Controller.api.bindevent();
},//edit方法同理
edit: function () {$("#plupload-video_file").data('upload-success',function(res){//console.log(res);$("#video").attr('src',res.url);});var video = document.getElementById('video');var canvas = document.createElement('canvas');var ctx = canvas.getContext('2d');width = video.clientWidth;height = video.clientHeight;video.addEventListener('loadeddata', function (e) {// console.log('loadeddata')this.currentTime=1.5;canvas.width = this.videoWidth;canvas.height = this.videoHeight;width = this.videoWidth;height = this.videoHeight;// console.log(width, height)// console.log(this)var currentTime = this.currentTime;var that=this;setTimeout(function(){ctx.drawImage(that, 0, 0, width, height);var src = canvas.toDataURL('image/jpeg');console.log(src);$("#fengmianinput").attr('value',src);$("#fengmian").attr('src',src);},200);});Controller.api.bindevent();},

需要注意的是，这里的默认封面图（上传视频自动截取的图），图片编码是base64，数据库需要用longtext类型。

在使用框架生成视频上传功能后，不要忘记设置可以上传的视频类型以及大小。