/// <summary>
        /// If the user clicks the X in the upper right of the form, this is where we stop and clean up
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void PreviewForm_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            this.axWindowsMediaPlayer1.URL = "";

            closing = true;

            if (transcoder != null)
            {
                transcoder.Stop();
            }

            if (Directory.Exists(previewDirPath))
            {
                try
                {
                    Directory.Delete(previewDirPath, true);
                }
                catch (Exception ex)
                {
                    Debug.WriteLine("failed to delete preview directory: " + ex.ToString());
                }
            }
        }