Microsoft DirectX 9.0

Controlling Playback

This topic applies to Windows XP Service Pack 1 only.

In general, the MSVidCtl object controls the larger tasks, such as acquiring the DVD player, handling display, and controlling the graph, while the MSVidWebDVD object typically handles specific DVD control, such as disc navigation and playback. However, certain methods exist in both objects. Such methods should only be accessed through the MSVidCtl object. Accessing these duplicate methods using the MSVidWebDVD object will cause an error:

Playback speed, on the other hand, is controlled using the Rate property on the MSVidWebDVD object.

Because DVD authoring design is not enforced, you may find that your application will not work perfectly with all discs. For example, some discs have a single title that holds a complete movie made of chapters, while others may have a single movie broken across several titles. Discs are designed to work specifically with their own menu screens, not to make navigation or control easy for the Video Control. However, most MSVidWebDVD actions, such as navigating through titles, chapters, menu buttons, or screens, will work with most discs.

In addition, you cannot depend on a DVD to include text strings or parental levels appropriately, it is not possible to determine programmatically if a method or property can be used at any particular time, and there can be a lag between UOP setting changes and UOP messages. Therefore, rigorous error trapping is essential to designing a robust application. Ideally, applications will derive the most benefit from using the MSVidWebDVD object with custom-designed DVDs, such as educational or reference discs, where you can predict or control the disc design. For these discs, MSVidWebDVD presents a simple-to-use, full-featured object that allows you to quickly and easily design a complex interface for your DVDs.

See Also