How load and play videos with WPFMediaKit without faults?

Question

I’m trying to write a media playout software which rotates the contents. The program uses the WPFMediaKit.dll and DirectShowLib-2005.dll. Before I send out the sign to the screen, I load some media, the MediaOpened event handler pauses it and later there is a call to play. Later, when I don't need that media, I close and remove it. When I need it again, I load again. It works well for a few hours. Sometimes it doesn't load a video, but later loads it properly, but I don't know why. 1-2 hours later the memory usage is about 4GB and tries to load videos, but every loading is unsuccessful. The content doesn’t seem to be played and the MediaOpened event is never called. What is wrong? These are some codes related to the media usage. When everything is ok, it works well, memory usage keeps changing in a broad interval (400 to 5000MB). When I stop playing (but the program is working), memory usage reduces below 200MB. After it becomes wrong and I stop playing, memory usage doesn't decrease. Typical video resolution I use is about 5000 x 400 pixels.

How I load video: (Video_playing is an own class which uses WPFMediaKit.DirectShow.MediaPlayers and WPFMediaKit.DirectShow.Controls)

Video_playing video = new Video_playing(fname);
video.Width = 100;
video.Height = 20;
video.Name = "media";
video.MediaOpened += Video_MediaOpened;
mediasListBox.Items.Add(video);

MediaOpened function:

private void Video_MediaOpened(object sender, System.Windows.RoutedEventArgs e)
        {
            if(enablePause)
                for (int i = 0; i < mediasListBox.Items.Count; i++)
                {
                    if (sender.Equals(mediasListBox.Items[i]))
                    {
                        ((Video_playing)mediasListBox.Items[i]).Pause();
                    }
                }
        }

How I remove and close an unused content:

if (mediasListBoxInfo[i][1].Equals("media"))
{
      ((Video_playing)mediasListBox.Items[i]).MediaOpened -= Video_MediaOpened;
      ((Video_playing)mediasListBox.Items[i]).UnloadedBehavior = WPFMediaKit.DirectShow.MediaPlayers.MediaState.Close;
      ((Video_playing)mediasListBox.Items[i]).Close();
}
mediasListBoxInfo.RemoveAt(i);
mediasListBox.Items.RemoveAt(i);