JG82852GMSL7VP Datasheet, PDF (137/176 Pages) Intel Corporation – Intel® 852GM/852GMV Chipset Intel® 852GM/852GMV Chipset Hub (GMCH)

Functional Description
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serration or feathering of moving edges when there is motion in the scene. Vertical filtering or “Bob”
interpolates adjacent lines rather replicating the nearest neighbor. This is the best solution for images
with motion however, it will have reduced spatial resolution in areas that have no motion and introduce
jaggies. In absence of any other de-interlacing, these form the baseline and are supported by the GMCH.
5.4.8.
5.4.8.1.
5.4.8.2.
5.4.8.3.
Video Functionality
The GMCH supports MPEG-2 decoding hardware, sub-picture support and DTV all format decode.
MPEG-2 Decoding
The GMCH MPEG2 Decoding supports Hardware Motion Compensation (HWMC). The GMCH can
accelerate video decoding for the following video coding standards:
MPEG-2 support
MPEG-1: Full feature support
H.263 support
MPEG-4: Only supports some features in the simple profile.
The GMCH HWMC interface is optimized for Microsoft’s* VA API. Hardware Video Acceleration
API (HVA) is a generic DirectDraw and DirectShow interface supported in Windows 2000 and
Windows 98 Millennium to provide video decoding acceleration. Direct VA is the open standard
implementation of HVA, which is natively supported by the GMCH hardware.
Hardware Motion Compensation
The Hardware Motion Compensation (HWMC) process consists of reconstructing a new picture by
predicting (either forward, backward, or bi-directional) the resulting pixel colors from one or more
reference pictures. The GMCH receives the video stream and implements Motion Compensation and
subsequent steps in hardware. Performing Motion Compensation in hardware reduces the processor
demand of software-based MPEG-2 decoding, and thus improves system performance.
Sub-picture Support
Sub-picture is used for two purposes: Subtitles for movie captions, which are superimposed on a main
picture, and for Menus to provide some visual operation environments for the user.
DVD allows movie subtitles to be recorded as Sub-pictures. On a DVD disc, it is called “Subtitle”
because it has been prepared for storing captions. Since the disc can have a maximum of 32 tracks for
Subtitles, they can be used for various applications, for example, as Subtitles in different languages.
There are two kinds of Menus, the System Menus and other In-Title Menus. First, the System Menus are
displayed and operated at startup of or during the playback of the disc or from the stop state. Second, In-
Title menus can be programmed as a combination of Sub-picture and Highlight commands to be
displayed during playback of the disc.
The GMCH supports sub-picture for DVD and DBS by mixing the two video streams via alpha
blending. Unlike color keying, alpha blending provides a softer effect and each pixel that is displayed is
a composite between the two video stream pixels. The GMCH can utilize four methods when dealing
with sub-pictures. This flexibility means that the GMCH can work with all sub-picture formats.
Intel^® 852GM/852GMV Chipset GMCH Datasheet
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