Displaying an Application-Supplied Bitmap on the Composited Image

This topic applies to Windows XP Home Edition and Windows XP Professional only.

To display an alpha-blended bitmap image over the video rectangle, the application must force the VMR to load its mixer, even if there is only a single video stream. The VMR uses its mixer component to overlay the bitmap onto the composited image. Applications can use this feature to display channel logos, a user interface, or advertisements either partially or completely within the video rectangle. Because the blending is performed in hardware by the graphics processor, there is minimal impact to the playback performance of the Video Stream, and there are no detectable flicker or tearing artifacts. Applications can change the image displayed as frequently as they wish. It should be noted that changes are only reflected on the screen when the DirectShow filter graph is in the running state.