#region //运行FFMpeg的视频解码，(这里是绝对路径)
        /// <summary>
        /// 转换文件并保存在指定文件夹下面(这里是绝对路径)
        /// </summary>
        /// <param name="fileName">上传视频文件的路径（原文件）</param>
        /// <param name="playFile">转换后的文件的路径（网络播放文件）</param>
        /// <param name="imgFile">从视频文件中抓取的图片路径</param>
        /// <returns>成功:返回图片虚拟地址;   失败:返回空字符串</returns>
        public string ChangeFilePhy(string fileName, string playFile, string imgFile)
        {
            //取得ffmpeg.exe的路径,路径配置在Web.Config中,如:<add   key="ffmpeg"   value="E:\51aspx\ffmpeg.exe"   />   
            start = DateTime.Now;
            string ffmpeg = ffmpegtool;
            if ((!System.IO.File.Exists(ffmpeg)) || (!System.IO.File.Exists(fileName)))
            {
                return "";
            }

            //获得图片和(.flv)文件相对路径/最后存储到数据库的路径,如:/Web/User1/00001.jpg   

            string flv_file = System.IO.Path.ChangeExtension(playFile, ".flv");


            //截图的尺寸大小,配置在Web.Config中,如:<add   key="CatchFlvImgSize"   value="240x180"   />   
            string FlvImgSize = VideoToFlv.sizeOfImg;
            System.Diagnostics.Process FilesProcess = new System.Diagnostics.Process();
            FilesProcess.StartInfo.FileName = ffmpeg;
            FilesProcess.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
            FilesProcess.StartInfo.Arguments = " -i " + fileName + " -ab 56 -ar 22050 -b 500 -r 30 -s " + widthOfFile + "x" + heightOfFile + " " + flv_file;
            try
            {
                FilesProcess.Start();
                while (!FilesProcess.HasExited)
                { 

                }
                //截图
                CatchImg(fileName, imgFile);
                WriteRunTime();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
               
            }
            return "";
        }
        #endregion