外文翻译----视频会议通过tcpip协议在个人电脑上的实现(编辑修改稿)

外文翻译----视频会议通过tcpip协议在个人电脑上的实现(编辑修改稿)内容摘要：

evice drivers share many properties with the hardware device drivers but implement TCP/IP protocols and other software features of the system. Device drivers are extremely powerful as they access the hardware and software at a privileged level in all versions of Windows. Even in Windows and Windows 95, which can allow applications to overwrite memory within the operating system or other applications, device drivers operate at a privileged level which allows the drivers to do even more damage than an application. Because of this device drivers can cause severe problems, inexplicable crashes, and strange conflicts between devices. Most configuration and installation problems involve the device drivers. While it is impossible to anticipate the many situations that will be encountered in the field, this document provides an overview of the installation and configuration issues for videoconferencing systems on PC’s over TCP/IP works. Video Display Videoconferencing systems make heavy use of the PC’s video display: video adapter card and video drivers. Video display drivers can contain subtle bugs that can conflict with applications, including the videoconferencing applications, causing many problems including general protection faults and updating problems on the screen. In general, make sure to have the latest drivers for a video card. Most major video card and video chip vendors provide drivers on their Web sites and ftp sites. Use the video card drivers rather than generic video chip drivers where possible. For example, for Diamond Multimedia video cards, both Diamond and S3, the manufacturer of the video chips used in the Diamond Multimedia video cards, provide video drivers. Diamond has substantially enhanced the drivers for Diamond cards over the drivers provided by S3. It can be very unclear that a faulty display driver is the cause of a problem in a PC. The digital video standards used in videoconferencing such as and work in the YCrCb color space rather than the RGB color space used by video cards and monitors. The latest generations of video chips provide hardware color space conversion. The chip converts the decoded video from the YCrCb (luminancecolor difference) video into RGB in hardware, providing a substantial speedup. Many chips provide hardware accelerated scaling of images. The need or desire to install a video card with these advanced features may arise. Under Windows 95, color space conversion and scaling are accessed through the DirectDraw API. The DirectDraw HAL (Hardware Abstraction Layer) provides the actual device driver. Under Windows , the standard Graphic Device Interface (GDI) provides no support for hardware color space conversion or scaling. The standard device drivers for video cards under Windows are GDI device drivers. Intel defined a standard。