using (FileStream fread = new FileStream(@"C:\Users\kyp10\Desktop\1、复.avi", FileMode.OpenOrCreate, FileAccess.Read))

 {

     using (FileStream fwrite = new FileStream(@"C:\Users\kyp10\Desktop\new.avi", FileMode.OpenOrCreate, FileAccess.Write))

     {

       while (true)

        {

           byte[] buffer = new byte[ *  * ];

           int r = fread.Read(buffer, , buffer.Length);

           if (r == )

           {

            break;

        }

       fwrite.Write(buffer, , r);

    }

    }
}