$this->upload->initialize($config);
$this->load->library(\'upload\', $config);

if(!$this->upload->do_upload($file))
{
// If there is any error
$err_msgs .= \'Error in Uploading video \'.$this->upload->display_errors().\'<br />\';
}
else
{
$data=array(\'upload_data\' => $this->upload->data());
$video_path = $data[\'upload_data\'][\'file_name\'];
  $directory_path = $data[\'upload_data\'][\'file_path\'];
$directory_path_full      = $data[\'upload_data\'][\'full_path\'];
$file_name = $data[\'upload_data\'][\'raw_name\'];

// ffmpeg command to convert video

exec(\"ffmpeg -i \".$directory_path_full.\" \".$directory_path.$file_name.\".flv\");

// $file_name is same file name that is being uploaded but you can give your custom video name after converting So use something like myfile.flv.

/// In the end update video name in DB
$array = array(
\'video\' => $file_name.\'.\'.\'flv\',
);
$this->db->set($array);
$this->db->where(\'id\',$id); // Table where you put video name
$query = $this->db->update(\'user_videos\');
}