作者MCEVid.doc

Recommendations for the Best Viewing Experience
Video quality from graphics hardware is largely determined by the capabilities and quality of the hardware and the device driver. To troubleshoot video quality problems that may be caused by the graphics hardware device driver, review the following points:
• Check that video acceleration is enabled in the display driver.
To check hardware acceleration, run a utility such as MCDiag or the Microsoft® DirectX® Diagnostic Viewer (DXDiag) that reports support for DirectX Video Acceleration (DirectX VA). These utilities are included with DirectX 9.0.
• Optimize for improved video rendering frame rate by taking advantage of the DeinterlaceBltEx extension to DirectX VA.
The DeinterlaceBltEx call enables more efficient use of the graphics hardware so that deinterlacing and subpicture blending can be performed with a single driver call.
• Confirm video headroom and toeroom are preserved with proper colorspace conversion.
Play test material found on DVDs, such as the Avia Guide to Home Theater or THX Optimizer in Media Center, and look for all gray values present in the brightness and contrast tests. Graphics hardware with an incorrect colorspace conversion will result in the end user not being able to discern the entire test pattern on these DVDs.
• Verify that the deinterlacing is not degrading image quality by comparing the various deinterlace modes supported by the driver.
Graphics drivers can expose more than one hardware deinterlacing mode. The deinterlacing mode used by Microsoft® Windows® XP Media Center Edition is controlled by the following registry key:

HKLM\Software\Microsoft\Windows\CurrentVersion\
Media Center\Service\Video\Deinterlace Technology

Setting a value of 0x1F causes Media Center video to be deinterlaced with the equivalent of a bob algorithm. Setting the value to the default value of 0x7F enables adaptive deinterlacing for video in Media Center, if it is supported by the display driver and graphics accelerator. Currently, end users do not have access to this setting through the Media Center user interface.
Often the best analysis of deinterlacing quality can be found by using reference video material and performing competitive analysis across a variety of graphics platforms to determine which offers the result with the fewest visual artifacts and the most appealing image.