รบกวนสอบถามการ Upload ไฟล์วีดีโอ หาค่าความยาวเวลาของไฟล์คลิป ASP.Net

public string f_VideoDuration((add path)parameters)
        {

            try
            {

                string sInputVideo = Page.MapPath(add path);

                string sPath = " -i " + sInputVideo ;

                Process ffmepg = new Process();
                ffmepg.StartInfo.FileName = (Server.MapPath(ffmpeg.exe"));
                ffmepg.StartInfo.UseShellExecute = false;
                ffmepg.StartInfo.RedirectStandardOutput = true;
                ffmepg.StartInfo.RedirectStandardError = true;
                ffmepg.StartInfo.CreateNoWindow = true;
                ffmepg.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
                ffmepg.StartInfo.Arguments = sPath;
                ffmepg.EnableRaisingEvents = true;
                ffmepg.Start();
                string sDuration = ffmepg.StandardError.ReadToEnd().ToString();
                ffmepg.Close();
                ffmepg.Dispose();
                sDuration = sDuration.Remove(0, sDuration.LastIndexOf("Duration: ") + 10);
                sDuration = sDuration.Substring(0, sDuration.IndexOf(","));
                return sDuration;
            }
            catch (Exception ex)
            {
                throw (ex);
            }
        }