Intel 82854 GMCH - Manual (Page 18)

18 Intel® Digital Set Top Box Display Driver
User’s Guide for Microsoft* Windows* CE 5.0
4.1.4 2D Graphics Options
The display driver support options to control 2D rendering. Some of these also affect video rendering.
[HKEY_LOCAL_MACHINE\Drivers\Display\Intel]
SysToVidStretch <DWORD>
This key determines if the system to video stretch BLT functionality is enabled in the driver.
0 = disabled
1 = enabled
BlendFilter <DWORD>
This key determines the blending filter used for 2D stretch BLTs via GDI stretch BLT and DirectDraw AlphaBlt
routines. It only affects GDI stretch BLTs when the GDI stretch blit mode is set to BILINEAR through the
SetStretchBltMode GDI API. It only affectsAlphaBlt-based stretch blits when the DDABLT_FILTERENABLE flag
is used.
1 = Bilinear
2 = Anisotropic
BlitSyncVBI <DWORD>
This key determines if a 2D BLT operation will be blocked until the vertical blanking interval before executing. The
BLT occurs during the vertical blanking period, which updates the frame buffer when active data is not being
displayed. This can be used to prevent tearing if BLT operations are being requested directly on to the primary
frame buffer.
Note: This key enabled for GDI only, not DirectDraw – If DirectDraw is used, double buffering should be used to
accomplish this because flipping the back buffer on-screen will sync to the vertical blanking interval automatically.
Flipping will utilize less CPU than using BlitSyncVBI because BlitSyncVBI busy waits for the vertical blanking
interval within the display driver, whereas flipping is asynchronous.
0 = disabled
1 = enabled
InterlacedToProgressiveAutoBob <DWORD>
This key determines whether hardware bob will be automatically enabled for overlays if interleaved (woven) source
is provided and the GMCH is in a progressive display mode. If this key is disabled, hardware bob will not be
automatically enabled for overlays.
Note: The driver dynamically checks the state of this registry key value whenever
IDirectDrawSurface5::UpdateOverlay
is called to show the overlay.
Note: This registry key value is only supported on the 830 and 854 GMCH.
0 = disabled
1 = enabled (default)