Reader of SWF Header File in Pure C#

/* Not using below case as i not able to dispose the swfReader object which can result in unnecessary memory*/

// Create a swf stream reader
SwfReader swfReader = new SwfReader(path);
// Read the completed swf file
Swf swf = swfReader.ReadSwf();
// Read only headers of file to optimize read speed
//Swf swf = swfReader.ReadSwfHeader();
int swfHeight = swf.Header.Height;
int swfWidth = swf.Header.Width;
swfReader.Close();
if ((swfHeight > int.Parse(hdnBannerHeight.Value)) || (swfWidth > int.Parse(hdnBannerWidth.Value)))
{
    lblImageUploadMessage1.Text = "File cant be upload as it has invalid dimensions";
    lblImageUploadMessage1.CssClass = "lblErrorMSG";
    Session["bannerImage"] = null;
    if (System.IO.File.Exists(path)) { System.IO.File.Delete(path); }
}

private int m_Duration = 0;
internal int Duration {
  get { return m_Duration; }
}

private void ReadDuration() {
  //Dauer des Videos ermitteln
  int int32ByteSize = 4;
  byte[] bytes = new byte[int32ByteSize];
  for (int i = 0; i < int32ByteSize; i++) {
    bytes[i] = GetNextByte();
  }

  m_Duration = ByteArrayToInt32(bytes, true);
}

private static Int32 ByteArrayToInt32(byte[] bytes, bool readInReverse = false) {
  // Check if has 4 Bytes
  if (bytes.Length != 4) { throw new Exception("bytes must be exactly 4 in Length"); }
  if (readInReverse) { Array.Reverse(bytes); }
  return BitConverter.ToInt32(bytes, 0);
}

private TimeSpan m_DurationSpan = new TimeSpan(m_Duration)

FileStream fs = File.OpenRead(fileName);
data = new byte[100];
fs.Read(data, 0, 100);
fs.Close();