Thumb nail form flv file

Question

hi every one . I am making a websit in which client want to show video gallery like u tube . on internet i found use of ffmpeg. i have download ffmpeg adn pest it in root directry. and create class

  <?php
          class media_handler
          {
                 function convert_media($filename, $rootpath, $inputpath,$outputpath,$width, $height, $bitrate, $samplingrate)
          {
            $outfile = "";

                  $rPath = $rootpath."\ffmpeg";

                $size = $width."x".$height;

                     $outfile =$filename;




                 $size = Width & "x" & Height;



                     $outfile = 'out_file.flv';


               $ffmpegcmd1 = "ffmpeg -i '".$inputpath."'\'".$filename. "' -acodec mp3    -ar '" .$samplingrate."' -ab '".$bitrate."'
                   -f flv -s '".$size."' '".$outputpath."'\'".$outfile;
               $ret = shell_exec($ffmpegcmd1);


                   return $outfile;
                     }


                  function set_buffering($filename,$rootpath,$path)
                   {

                   $_rootPath = $rootpath."\flvtool";



                 $ffmpegcmd1 = "flvtool2 -U '".$Path."'\'".$filename;
                     $ret = shell_exec($ffmpegcmd1);


                }



                      function grab_image($filename, $rootpath, $inputpath,$outputpath, $no_of_thumbs, $frame_number, $image_format, $width, $height)
               {

                       $_rootpath ="ffmpeg";

                  $size = $width. "x".$height;


                  $outfile = "sample.png";

                     $ffmpegcmd1 = "ffmpeg -i '".$inputpath."'\'".$filename."' -vframes '".$no_of_thumbs."' -ss 00:00:03 -an -vcodec '". $image_format."' -frawvideo -s '".$size. "''". $outputpath."'\'".$outfile ;

               $ret = shell_exec($ffmpegcmd1);



                return $outfile;
             }
                     }

and where i have used this the code is

                      $outfile=$_FILES['videofile']['name'];
$rootpath =$videoPath;
$outputpath=$videoPath;
$thumbpath=$videoPath;
     **$image_name = $_mediahandler->grab_image($outfile, $rootpath, $outputpath, $thumbpath, 1, 2, "png", 110, 90);**

but it is not working .