Flipping Overlay Surfaces (Windows CE 5.0)
Like other types of surfaces, you can create overlay flipping chains. After creating a flipping chain of overlays, call the IDirectDrawSurface5::Flip method to flip between them. For more information, see Flipping Surfaces.
Software decoders displaying video with overlay surfaces can use the DDFLIP_ODD and DDFLIP_EVEN flags when calling the Flip method to use capabilities that reduce motion artifacts.
If the driver supports odd-even flipping, the DDCAPS2_CANFLIPODDEVEN flag will be set in the DDCAPS structure after retrieving driver capabilities.
If DDCAPS2_CANFLIPODDEVEN is set, you can include the DDOVER_BOB flag when calling the IDirectDrawSurface5::UpdateOverlay method to inform the driver that you want it to use the Bob algorithm to minimize motion artifacts.
Later, when you call Flip with the DDFLIP_ODD or DDFLIP_EVEN flag, the driver will automatically adjust the overlay source rectangle to compensate for jittering artifacts.
If the driver does not set the DDCAPS2_CANFLIPODDEVEN flag when you retrieve hardware capabilities, UpdateOverlay will fail if you specify the DDOVER_BOB flag.
For more information about the Bob algorithm, see Solutions to Common Video Artifacts.
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