private void ResetMissingImages ()
{
if (missing_audio_image != null) {
((IDisposable)missing_audio_image).Dispose ();
var disposed = missing_audio_image;
missing_audio_image = null;
if (current_image == disposed) {
current_image = MissingAudioImage;
}
if (incoming_image == disposed) {
incoming_image = MissingAudioImage;
}
}
if (missing_video_image != null) {
((IDisposable)missing_video_image).Dispose ();
var disposed = missing_video_image;
missing_video_image = null;
if (current_image == disposed) {
current_image = MissingVideoImage;
}
if (incoming_image == disposed) {
incoming_image = MissingVideoImage;
}
}
}