public void WatermarkVideoClip()
        {
            // this demonstrates one way of watermarking a video clip...

            string outputFile = "WatermarkVideoClip.wmv";

            using (ITimeline timeline = new DefaultTimeline(15))
            {
                // greate our default audio track
                timeline.AddAudioGroup().AddTrack();

                // add a video group, 32bpp, 320x240 (32bpp required to allow for an alpha channel)
                IGroup videoGroup = timeline.AddVideoGroup(32, 320, 240);

                // add our default video track
                ITrack videoTrack = videoGroup.AddTrack();

                // add another video track, this will be used to contain our watermark image
                ITrack watermarkTrack = videoGroup.AddTrack();

                // add the video in "transitions.wmv" to the first video track, and the audio in "transitions.wmv"
                // to the first audio track.
                timeline.AddVideoWithAudio("transitions.wmv");

                // add the watermark image in, and apply it for the duration of the videoContent
                // this image will be stretched to fit the video clip, and in this case is a transparent gif.
                IClip watermarkClip = watermarkTrack.AddImage("testlogo.gif", 0, videoTrack.Duration);

                // add a alpha setter effect to the image, this will adjust the alpha of the image to be 0.5
                // of it's previous value - so the watermark is 50% transparent.
                watermarkClip.AddEffect(0, watermarkClip.Duration, StandardEffects.CreateAlphaSetterRamp(0.8));

                // add a transition to the watermark track, this allows the video clip to "shine through" the watermark,
                // base on the values present in the alpha channel of the watermark track.
                watermarkTrack.AddTransition(0, videoTrack.Duration,
                                             StandardTransitions.CreateKey(KeyTransitionType.Alpha, null, null, null,
                                                                           null,
                                                                           null),
                                             false);
                using (
                    // render it to windows media
                    var renderer =
                        new WindowsMediaRenderer(timeline, outputFile, WindowsMediaProfiles.HighQualityVideo))
                {
                    renderer.Render();
                }
            }
        }