Video Streams

STK Engine provides a robust video reader based on RasterStream. VideoStream supports streaming from various protocols and a large variety of media formats, codecs, frame rates and frame sizes. See below for the complete list.

Both real-time playback of video and synchronization of video with the time in STK Engine is provided by the VideoStream class. When playing in real-time, the video will play at the rate defined by the video stream, or at the frame rate specified with the FrameRate property. If the Loop property is set to true, the video will loop to the first frame when it reaches past the last frame of the video.

Below, a VideoStream is loaded from an HTTP source:

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IAgStkGraphicsSceneManager manager = ((IAgScenario)root.CurrentScenario).SceneManager; string uri = @"http://www.agi.com/downloads/media-center/multimedia/current-events/us-spy-satellite/US_ASAT.wmv"; IAgStkGraphicsVideoStream videoStream = manager.Initializers.VideoStream.InitializeWithStringUri(uri); videoStream.Playback = AgEStkGraphicsVideoPlayback.eStkGraphicsVideoPlaybackRealTime; videoStream.Loop = true;

The StartTime, EndTime, StartFrame, and EndFrame properties can be used to adjust where the video starts playback and where it ends. Since these properties are interrelated, changing the StartTime will also change the StartFrame, and vice versa. The EndTime and EndFrame properties follow the same convention.

When playback is set to synchronize with a time interval by setting the Playback property to TimeInterval, the video will play synchronized with the time interval specified with the IntervalStartTime and IntervalEndTime properties. The start frame of the video will coincide with the start time of the interval, and the last frame of the video will coincide with the end time of that interval. For example, when the STK Engine animation is played in reverse, or stepped to a specific time, the video will similarly play in reverse or step to the corresponding frame in the video at that time.

Below, a VideoStream is configured to play synchronized over a time interval:

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IAgStkGraphicsSceneManager manager = ((IAgScenario)root.CurrentScenario).SceneManager; IAgStkGraphicsVideoStream videoReader = manager.Initializers.VideoStream.InitializeWithStringUri(videoPath); videoReader.Playback = AgEStkGraphicsVideoPlayback.eStkGraphicsVideoPlaybackTimeInterval; videoReader.IntervalStartTime = root.ConversionUtility.NewDate("UTCG", ((IAgScenario)root.CurrentScenario).StartTime.ToString()); videoReader.IntervalEndTime = root.ConversionUtility.NewDate("UTCG", "30 May 2008 14:11:58.162");

As with any Raster and RasterStream, the VideoStream can be queried for its attributes and data:

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IAgStkGraphicsRaster videoData = videoReader as IAgStkGraphicsRaster; Console.WriteLine(videoData.Attributes.Width); Console.WriteLine(videoData.Attributes.Height); Console.WriteLine(videoData.Attributes.Format); Console.WriteLine(videoData.Attributes.PixelAspectRatio);

STK Programming Interface 11.0.1