ffmpeg to validate video format is genune and store error into string

Question

Since there are hackers uploading malicious software's in name of video extensions(.mp4,webm..etc) in websites. I tried to validate videos uploaded from file upload in asp.net.This website helped me to find a way to do this operation using ffmpeg https://superuser.com/questions/100288/how-can-i-check-the-integrity-of-a-video-file-avi-mpeg-mp4 I tried to do this operation in asp.net and failed due to errors since my first time using ffmpeg.below is my code.I tried to save malicious software creates error in to a string.

       Process ffmpeg; 
       string video;
       string thumb="";
       video = Page.MapPath("") + "\\input\\error.mp4";
       ffmpeg = new Process();
       ffmpeg.StartInfo.Arguments = "-v error -i \"" + video + "\"-f null - 2> \"" + thumb + "\"";
       ffmpeg.StartInfo.FileName = Page.MapPath("ffmpeg//ffmpeg.exe");
       ffmpeg.Start(); // start !
       ffmpeg.StartInfo.CreateNoWindow = true;
       ffmpeg.WaitForExit();
       Label1.Text = thumb;

please also let me know if there is any other option other than ffmpeg