6 1738 ch15 7/30/04 10:31 AM Page 867 CHAPTER15 Video Hardware
16 1738 ch15 7/30/04 868 10:31 AM Chapter 15 Page 868 Video Hardware Video Display Technologies Along with the mouse and keyboard, the video display is a vital part of the user interface of any computer. Actually, it is a latecomer to computing; before CRT monitors came into general use, the teletypewriter was the standard computer interface—a large, loud device that printed the input and output characters on a roll of paper.
16 1738 ch15 7/30/04 10:31 AM Page 869 Video Display Technologies Chapter 15 869 have a good match between persistence and scanning frequency so the image has less flicker (which occurs when the persistence is too low) and no ghost images (which occurs when the persistence is too high). Integral implosion protection Deflection yoke Electron gun assembly Shadow mask Glass panel Internal magnetic shield Glass funnel Red, green, and blue phosphors Figure 15.
16 1738 ch15 7/30/04 870 10:31 AM Chapter 15 Page 870 Video Hardware vendors have used a variety of trade names to identify their multiple-frequency monitors, including multisync, multifrequency, multiscan, autosynchronous, and autotracking among others. Note Even though a monitor is capable of displaying a wide range of video standards, you usually need to fine-tune the display through its onscreen display (OSD) controls and Windows display properties sheets to achieve the best possible pictures.
16 1738 ch15 7/30/04 10:31 AM Page 871 Video Display Technologies Chapter 15 871 DVI—Digital Signals for CRT Monitors The latest trend in CRT monitor design is the use of digital input signals using the same Digital Video Interface (DVI) standard used for LCD flat-panel displays.
16 1738 ch15 7/30/04 872 10:31 AM Chapter 15 Figure 15.3 quarters. Page 872 Video Hardware Note the small footprint of this 15'' LCD, which makes these panels ideal for use in cramped Two basic LCD choices are available today on notebook computers: active-matrix analog color and active-matrix digital—the latest development. Monochrome LCDs are obsolete for PCs, although they remain popular for Palm and similar organizer devices and are sometimes used for industrial display panels.
16 1738 ch15 7/30/04 10:31 AM Page 873 Video Display Technologies Chapter 15 873 How LCDs Work In an LCD, a polarizing filter creates two separate light waves. The polarizing filter allows light waves that are aligned only with the filter to pass through. After passing through the polarizing filter, the remaining light waves are all aligned in the same direction. By aligning a second polarizing filter at a right angle to the first, all those waves are blocked.
16 1738 ch15 7/30/04 874 10:31 AM Chapter 15 Page 874 Video Hardware Hitachi’s Super-IPS technology also rearranges the liquid crystal molecules into a zig-zag pattern, rather than the typical row-column arrangement, to reduce color shift and improve color uniformity. The similar multidomain vertical alignment (MVA) technology developed by Fujitsu divides the screen into different regions and changes the angle of the regions.
16 1738 ch15 7/30/04 10:31 AM Page 875 Video Display Technologies Chapter 15 875 Pin 1 Pin 1 DVI-D connector VGA connector Pin 1 DFP connector Pin 1 DVI-I connector C1 C2 C5 C3 C4 Figure 15.4 Conventional VGA cards, CRTs, and analog-compatible LCDs use the standard VGA connector. Early digital LCDs and their matching video cards often used the DFP connector.
16 1738 ch15 7/30/04 876 10:31 AM Chapter 15 Page 876 Video Hardware ■ High-quality LCD panels of either digital or analog type are great for displaying sharp text and graphics. But they often can’t display as wide a range of very light and very dark colors as CRTs can. ■ Many LCDs don’t react as quickly as CRTs. This can cause full-motion video, full-screen 3D games, and animation to look smeared onscreen. To avoid this problem, look for LCDs that offer a response time of 16ms or faster.
16 1738 ch15 7/30/04 10:31 AM Page 877 Video Display Technologies Chapter 15 877 your LCD monitor for group presentations. To improve the horizontal viewing area, several vendors have developed patented improvements to the basic TFT display, such as Hitachi’s in-plane switching (IPS), Fujitsu’s multidomain vertical adjustment (MVA), and Mitsubishi’s FFD—all of which have been licensed to other leading LCD makers.
16 1738 ch15 7/30/04 878 10:31 AM Chapter 15 Page 878 Video Hardware SRAM Memory Processor Projection lens DMD micromirror array Shaping lens Color wheel Condensing lens Light source Figure 15.5 How a typical DLP projector works. The earliest DLP projectors used a simple three-color (RGB) wheel, as shown in Figure 15.5. However, more recent models have used a four-segment (RGB and clear) or a six-segment (RGBRGB) wheel to improve picture quality.
16 1738 ch15 7/30/04 10:31 AM Page 879 Video Display Technologies Dielectric layer Display electrode Chapter 15 879 Cover glass Phosphor triad (RGB) MgO layer RED GREEN BLUE Rear plate glass Address protective layer Address electrodes Figure 15.6 A cross-section of a typical plasma display. Video Adapter Types A monitor requires a source of input. The signals that run to your monitor come from a video adapter inside or plugged into your computer.
16 1738 ch15 7/30/04 880 10:31 AM Chapter 15 Page 880 Video Hardware The term video adapter applies to either integrated or separate video circuitry. The term graphics adapter is essentially interchangeable with video adapter because all video options developed since the original IBM monochrome display adapter (MDA) can display graphics as well as text.
16 1738 ch15 7/30/04 10:31 AM Page 881 Monitor Selection Criteria Chapter 15 881 Note One of the many reasons I don’t recommend low-cost computers sold by major retail stores is because they often are bundled with low-quality CRT or LCD monitors. Although 15'' CRT monitors are now less common than 17'' CRT monitors, many bundled monitors in either size have lower refresh rates, are bulkier, or have other deficiencies compared to high-quality thirdparty monitors.
1738 ch15 7/30/04 882 10:31 AM Chapter 15 Page 882 Video Hardware As PC video technology developed, the screen resolutions video adapters support grew at a steady pace. Table 15.2 shows standard resolutions used in PC graphics adapters and displays and the terms commonly used to describe them. Table 15.2 Graphics Display Resolution Standards Display Standard Linear Pixels (H×V) Total Pixels CGA 320×200 64,000 1.60 EGA 640×350 224,000 1.83 VGA 640×480 307,200 1.
16 1738 ch15 7/30/04 10:31 AM Page 883 Monitor Selection Criteria Chapter 15 883 onboard or, if you have motherboard chipset-based video, how much system memory is allocated to your video function. If you switch to a larger display and you can’t set the color depth you want to use, a new video card with more RAM is a desirable upgrade. Video cards once featured upgradeable memory, but this is no longer an option with current models.
16 1738 ch15 7/30/04 884 10:31 AM Chapter 15 Page 884 Video Hardware Dot Pitch (CRTs) Another important specification that denotes the quality of a given CRT monitor is its dot pitch, which is controlled by the design of the shadow mask or aperture grille inside the CRT. A shadow mask is a metal plate built into the front area of the CRT, next to the phosphor layers.
16 1738 ch15 7/30/04 10:31 AM Page 885 Monitor Selection Criteria Chapter 15 885 Some of NEC’s monitors use a variation on the aperture grille called the slotted mask, which is brighter than standard shadow-mask monitors and more mechanically stable than aperture grille–based monitors (see Figure 15.8). RGBRGBRGBRGBRGBRGBRG RBGRBGRGBRGBRGBRGBRGB Figure 15.
16 1738 ch15 7/30/04 886 10:31 AM Chapter 15 Page 886 Video Hardware For more information about interlaced displays, see “Interlaced Versus Noninterlaced” in Chapter 15 of Upgrading and Repairing PCs, 12th Edition, included in electronic form on the disc accompanying this book. Energy and Safety Monitors, like virtually all power-consuming computer devices, have been designed to save energy for a number of years.
16 1738 ch15 7/30/04 10:31 AM Page 887 Monitor Selection Criteria Table 15.
16 1738 ch15 7/30/04 888 10:31 AM Chapter 15 Page 888 Video Hardware If you aren’t using a low-emission monitor yet, you can take other steps to protect yourself. The most important is to stay at arm’s length (about 28 inches) from the front of your monitor. When you move a couple of feet away, ELF magnetic emission levels usually drop to those of a typical office with fluorescent lights.
16 1738 ch15 7/30/04 10:31 AM Page 889 Monitor Selection Criteria Chapter 15 889 A flicker-free refresh rate is a refresh rate high enough to prevent you from seeing any flicker. The flickerfree refresh rate varies with the resolution of your monitor setting (higher resolutions require higher refresh rates) and must be matched by both your monitor and display card. Because a refresh rate that is too high can slow down your video display, use the lowest refresh rate that is comfortable for you.
16 1738 ch15 7/30/04 890 10:31 AM Chapter 15 Page 890 Video Hardware Note Because CRT monitors are redrawing the screen many times per second, the change in a noninterlaced CRT screen display is virtually invisible to the naked eye, but it is very obvious when computer screens are photographed, filmed, or videotaped.
16 1738 ch15 7/30/04 10:31 AM Page 891 Monitor Selection Criteria Chapter 15 891 Horizontal Frequency Different video resolutions use different horizontal frequencies. For example, the standard VGA resolution of 640×480 requires a horizontal resolution of 31.5KHz, whereas the 800×600 resolution requires a vertical frequency of at least 72Hz and a horizontal frequency of at least 48KHz.
16 1738 ch15 7/30/04 892 10:31 AM Chapter 15 Page 892 Video Hardware Barrel distortion Pincushion distortion Parallelogram distortion Trapezoidal distortion Figure 15.9 Typical geometry errors in CRT monitors; these can be corrected on most models that have digital picture controls. Although LCD panels aren’t affected by geometry errors as CRT monitors can be, they can have their own set of image-quality problems, especially if they use the typical 15-pin analog VGA video connector.
16 1738 ch15 7/30/04 10:31 AM Page 893 Maintaining Your Monitor Chapter 15 893 ■ Display the Microsoft Windows desktop to check for uniform focus and brightness. Are the corner icons as sharp as the rest of the screen? Are the lines in the title bar curved or wavy? Monitors usually are sharply focused at the center, but seriously blurred corners indicate a poor design. Bowed lines can be the result of a poor video adapter or incorrect configuration of the monitor’s digital picture controls.
16 1738 ch15 7/30/04 894 10:31 AM Chapter 15 Page 894 Video Hardware How can you tell whether the monitor is really off or in standby mode? Look at the power LCD on the front of the monitor. A monitor that’s in standby mode usually has a blinking green or solid amber LCD in place of the solid green LCD displayed when it’s running in normal mode. Because monitors in standby mode still consume some power, they should be shut off at the end of the computing day.
16 1738 ch15 7/30/04 10:31 AM Page 895 Video Display Adapters Chapter 15 895 Obsolete Display Adapters Although many types of display systems were at one time considered to be industry standards, few of these are viable standards for today’s hardware and software. Note If you are interested in reading more about MDA, HGC, CGA, EGA, or MCGA display adapters, see Chapter 8 of Upgrading and Repairing PCs, 10th Anniversary Edition, included on the disc with this book.
16 1738 ch15 7/30/04 896 √√ 10:31 AM Chapter 15 Page 896 Video Hardware See “Video Adapter BIOS,” p. 523. Other implementations of the VGA differ in their hardware but respond to the same BIOS calls and functions. New features are added as a superset of the existing functions, and VGA remains compatible with the graphics and text BIOS functions built into the PC systems from the beginning.
16 1738 ch15 7/30/04 10:31 AM Page 897 Video Display Adapters 897 Chapter 15 SVGA provides capabilities that surpass those offered by the VGA adapter. Unlike the display adapters discussed so far, SVGA refers not to an adapter that meets a particular specification, but to a group of adapters that have different capabilities.
16 1738 ch15 7/30/04 898 10:31 AM Chapter 15 Page 898 Video Hardware through additional code added to the VGA BIOS chip itself (the more common solution). The benefit of the VESA BIOS extension is that a programmer needs to worry about only one routine or driver to support SVGA. Various cards from various manufacturers are accessible through the common VESA interface.
16 1738 ch15 7/30/04 10:31 AM Page 899 Video Display Adapters Chapter 15 899 processors in the 845 and 865 families. Table 15.8 compares the major video features of Intel’s 8xxseries chipsets, which include integrated video. Note that chipsets listed together share the same video features but differ in other ways such as memory support, I/O features, and so forth. Table 15.
16 1738 ch15 7/30/04 900 10:31 AM Chapter 15 Table 15.
16 1738 ch15 7/30/04 10:31 AM Page 901 Video Display Adapters Chapter 15 901 Heatsinks over GDDR-3 memory chips Connectors to system power supply Cooling fan over 6800 Ultra GPU GDDR-3 memory chips TV-out (S-video) AGP 4x/8x slot connector DVI-out (can be converted to VGA-out) Power connector for fan Figure 15.11 A typical example of a high-end video card based on the NVIDIA GeForce FX 6800 Ultra GPU, a GPU optimized for gaming and dual-display support.
16 1738 ch15 7/30/04 902 10:31 AM Chapter 15 Page 902 Video Hardware The Video Processor The video processor, or chipset, is the heart of any video adapter and essentially defines the card’s functions and performance levels. Two video adapters built using the same chipset often have many of the same capabilities and deliver comparable performance.
16 1738 ch15 7/30/04 10:31 AM Page 903 Video Display Adapters Chapter 15 903 Video RAM Most video adapters rely on their own onboard memory that they use to store video images while processing them; although the AGP specification supports the use of system memory for 3D textures, this feature is seldom supported now that video cards routinely ship with 32MB, 64MB, or more of onboard memory.
16 1738 ch15 7/30/04 904 10:31 AM Chapter 15 Page 904 Video Hardware SDRAM Synchronous DRAM (SDRAM) is the same type of RAM used on many current systems based on processors such as the Pentium III, Pentium 4, Athlon, and Duron. The SDRAMs found on video cards are usually surface-mounted individual chips; on a few early models, a small module containing SDRAMs might be plugged into a proprietary connector.
16 1738 ch15 7/30/04 10:31 AM Page 905 Video Display Adapters Chapter 15 905 412MHz, versus the 9800 Pro’s 380MHz clock speed. Thus, the 9800 XT supports memory running at 730MHz, whereas the 9800 Pro supports memory running at 680MHz. By using the slower Pro part, vendors can use slower memory to create a less expensive graphics card.
16 1738 ch15 7/30/04 906 10:31 AM Chapter 15 Table 15.12 Page 906 Video Hardware Continued Resolution Color Depth Max.
16 1738 ch15 7/30/04 10:31 AM Page 907 Video Display Adapters Chapter 15 Table 15.13 Continued Resolution Color Depth Z-Buffer Depth Buffer Mode Actual Memory Used Onboard Video Memory Size Required 1024×768 16-bit 16-bit 24-bit 24-bit 32-bit1 32-bit Double Triple Double Triple Double Triple 4.50MB 6.00MB 6.75MB 9.00MB 9.00MB 12.00MB 8MB 8MB 8MB 16MB 16MB 16MB 16-bit 16-bit 24-bit 24-bit 32-bit 32-bit Double Triple Double Triple Double Triple 7.50MB 10.00MB 11.25MB 15.00MB 15.
16 1738 ch15 7/30/04 908 10:31 AM Chapter 15 Page 908 Video Hardware Windows Can’t Display More Than 256 Colors If you have a video card with 1MB or more of video memory, but the Windows Display Settings properties sheet won’t allow you to select a color depth greater than 256 colors, Windows might have misidentified the video card during installation or the video driver installation might be corrupted.
16 1738 ch15 7/30/04 10:31 AM Page 909 Video Display Adapters √√ See “Accelerated Graphics Port,” p. 364. √√ See “The PCI Bus,” p. 358. √√ See “PCI–Express,” p. 362. Chapter 15 909 The Accelerated Graphics Port (AGP), an Intel-designed dedicated video bus introduced in 1997, delivers a maximum bandwidth up to 16 times larger than that of a comparable PCI bus. AGP has been the mainstream high-speed video standard for several years.
16 1738 ch15 7/30/04 910 10:31 AM Chapter 15 Page 910 Video Hardware video cards support AGP 8x; however, differences in GPU design, memory bus design, and core and memory clock speed mean (as always) that AGP 8x cards with faster and wider memory and faster GPU speeds provide faster performance than AGP 8x cards with slower and narrower components. Although some systems with AGP 4x or 8x slots use a universal slot design that can handle 3.3V or 1.5V AGP cards, others do not.
16 1738 ch15 7/30/04 10:31 AM Page 911 Video Display Adapters Chapter 15 911 Video drivers generally are designed to support the processor on the video adapter. All video adapters come equipped with drivers the card manufacturer supplies, but often you can use a driver the chipset maker created as well. Sometimes you might find that one of the two provides better performance than the other or resolves a particular problem you are experiencing.
16 1738 ch15 7/30/04 912 10:31 AM Chapter 15 Table 15.16 Page 912 Video Hardware Using Graphics Acceleration Settings to Troubleshoot Windows XP Acceleration Setting When to Use Effect of Setting Long-Term Solution Left* The display works in Safe or VGA mode but is corrupted in other modes. There’s no acceleration. Update display, DirectX, and mouse drivers. One click from left* 2D and 3D graphics driver problems; mouse driver problems. It disables all but basic acceleration.
16 1738 ch15 7/30/04 10:31 AM Page 913 Video Display Adapters Chapter 15 913 Moving the slider to the None setting (the far left) adds the SafeMode=2 directive to the [Windows] section of the Win.ini file in Windows 9x/Me. This disables all hardware acceleration support on all versions of Windows and forces the operating system to use only the device-independent bitmap (DIB) engine to display images, rather than bit-block transfers.
16 1738 ch15 7/30/04 914 10:31 AM Chapter 15 Page 914 Video Hardware After the hardware is in place, you can configure the display for each monitor from the Display control panel’s Settings page. The primary display is always fixed in the upper-left corner of the virtual desktop, but you can move the secondary displays to view any area of the desktop you like. You can also set the screen resolution and color depth for each display individually.
16 1738 ch15 7/30/04 10:31 AM Page 915 Video Display Adapters Chapter 15 915 Most recent video cards with multiple-monitor support feature a 15-pin analog VGA connector for CRTs, a DVI-I digital/analog connector for digital LCD panels, and a TV-out connector for S-video or composite output to TVs and VCRs.
16 1738 ch15 7/30/04 916 10:31 AM Chapter 15 Page 916 Video Hardware As Table 15.18 notes, some video cards that use a chipset capable of multiple-monitor support might not provide the additional DVI or VGA connector necessary to enable that support. Table 15.18 does not include video chipsets that support TV-out or video in-video out (VIVO) but do not support a second CRT or LCD display.
16 1738 ch15 7/30/04 10:31 AM Page 917 3D Graphics Accelerators Chapter 15 917 most video adapters began to take on many of the tasks involved in rendering 3D images, greatly lessening the load on the system processor and boosting overall system performance. There have been roughly eight generations of 3D graphics hardware on PCs, as detailed in Table 15.19. Table 15.
16 1738 ch15 7/30/04 918 10:31 AM Chapter 15 Page 918 Video Hardware applications use another process, called MIP mapping, which uses different versions of the same texture that contain varying amounts of detail, depending on how close the object is to the viewer in the three-dimensional space. Another technique, called depth cueing, reduces the color and intensity of an object’s fill as the object moves farther away from the viewer.
16 1738 ch15 7/30/04 10:31 AM Page 919 3D Graphics Accelerators Chapter 15 919 by real-life fighter pilots—is placed in front of dynamically changing graphics (such as scenery, other aircraft, sky detail, and so on). In this example, the area of the screen occupied by the cockpit windshield frame is not re-rendered. Only the area seen through the “glass” is re-rendered, saving time and improving frame rates for animation.
16 1738 ch15 7/30/04 920 10:31 AM Chapter 15 Page 920 Video Hardware ■ T-buffer. This technology eliminates aliasing (errors in onscreen images due to an undersampled original) in computer graphics, such as the “jaggies” seen in onscreen diagonal lines; motion stuttering; and inaccurate rendition of shadows, reflections, and object blur. The T-buffer replaces the normal frame buffer with a buffer that accumulates multiple renderings before displaying the image.
16 1738 ch15 7/30/04 10:31 AM Page 921 3D Graphics Accelerators Chapter 15 921 Single- Versus Multiple-Pass Rendering Various video card makers handle application of these advanced rendering techniques differently. The current trend is toward applying the filters and basic rendering in a single pass rather than multiple passes.
16 1738 ch15 7/30/04 922 10:31 AM Chapter 15 Page 922 Video Hardware Application Programming Interfaces Application programming interfaces (APIs) provide hardware and software vendors a means to create drivers and programs that can work quickly and reliably across a wide variety of platforms. When APIs exist, drivers can be written to interface with the API rather than directly with the operating system and its underlying hardware.
16 1738 ch15 7/30/04 10:31 AM Page 923 3D Graphics Accelerators Chapter 15 923 The following manufacturers’ products are not included in Table 15.20 for the reasons listed: ■ 3Dfx Interactive. Out of business; obtain last-available official and third-party drivers from www.voodoofiles.com. ■ 3Dlabs. Now manufacturers Open GL–compatible workstation cards only. ■ Intel. No longer manufactures graphics boards. ■ Micron. No longer manufactures chipsets. ■ VideoLogic.
16 1738 ch15 7/30/04 924 10:31 AM Page 924 Chapter 15 Table 15.20 Video Hardware Continued Manufacturer: ATI GPU (Codename) DirectX Version Hardware T&L Rendering Pipelines Programmable Vertex Shader Pipelines RADEON 9500 9 Yes 4 4 128-bit .15 micron AGP 8x RADEON 9000 PRO, 9000 (RV250) 8.1 Yes 4 2 128-bit .15 micron Updated 8500 core; dual-display (PRO); AIW; AGP 8x RADEON 9800 PRO (R350) 9 Yes 8 4 256-bit .
16 1738 ch15 7/30/04 10:31 AM Page 925 3D Graphics Accelerators Table 15.20 Chapter 15 925 Continued Manufacturer: Matrox GPU (Codename) DirectX Version Hardware T&L Rendering Pipelines Programmable Vertex Shader Pipelines Millennium P650, P750 (Parhelia-LX) 8.1 Yes 2 2 128-bit .15 micron Based on Parhelia-512; triple-head display; AGP 8x Parhelia (Parhelia-512) 8.1 Yes 4 4 256-bit .15 micron Has some DirectX 9 features; triplehead display; AGP 8x Memory Bus Mfr.
16 1738 ch15 7/30/04 926 10:31 AM Chapter 15 Table 15.20 Page 926 Video Hardware Continued Manufacturer: NVIDIA GPU/Card (Codename) DirectX Version Hardware T&L Rendering Pipelines Programmable Vertex Shader Pipelines GeForce4 Ti 4600-8x, 42008x (NV28) 8 Yes 4 2 128-bit .15 micron AGP 8x version of GeForce 4 Ti 4600 and 4200; dual-display GeForce FX 5800 (NV30) 9 Yes 8 1 128-bit .13 micron Dual-display; AGP 8x GeForce FX 5600 (NV31) 9 Yes 4 1 128-bit .
16 1738 ch15 7/30/04 10:31 AM Page 927 Upgrading or Replacing Your Video Card Table 15.20 Chapter 15 927 Continued Manufacturer: SiS GPU/Card (Codename) DirectX Version Hardware T&L Rendering Pipelines Programmable Vertex Shader Pipelines SiS315 7 Yes 2 Xabre 80 8.1 Yes Xabre 200, 400 8.1 Xabre 600 8.1 Memory Bus Mfr. Process Notes N/A 64-bit, 128-bit .15 micron AGP 4x 4 2 64-bit, 128-bit .15 micron AGP 4x Yes 4 2 128-bit .
16 1738 ch15 7/30/04 928 10:31 AM Chapter 15 Page 928 Video Hardware In many cases, a single device provides both features. However, if you need better 3D performance or features, more memory, or support for DVI digital displays, you need to replace your video card. TV Tuner and Video Capture Upgrades With a few notable exceptions, such as ATI’s Radeon All-in-Wonder and NVIDIA’s Personal Cinema series, most video cards don’t have TV tuner and video capture upgrade features built in.
16 1738 ch15 7/30/04 10:31 AM Page 929 Upgrading or Replacing Your Video Card Chapter 15 929 Note With the rise in popularity of Linux, many graphics card and GPU vendors now provide downloadable Linux drivers. Be sure to check compatibility carefully because some vendors customize drivers for different Linux distributions or might provide drivers that work with only certain Linux kernels or XFree86 drivers.
16 1738 ch15 7/30/04 930 10:31 AM Chapter 15 Page 930 Video Hardware Video Cards for Multimedia Multimedia—including live full-motion video feeds, videoconferencing, and animations—has become an important element of the personal computing industry and is helping to blur the once-solid lines between computer and broadcast media. As the demand for multimedia content increases, so do the capabilities of the hardware and software used to produce the content.
16 1738 ch15 7/30/04 10:31 AM Page 931 Video Cards for Multimedia Table 15.22 Chapter 15 931 Television Versus Computer Monitors Standard Year Est. Country Lines Rate Television NTSC 1953 (color) 1941 (b&w) U.S., Japan 525 60 fields/sec PAL 1941 Europe1 625 50 fields/sec SECAM 1962 France 625 25 fields/sec 640×4802 72Hz Computer VGA 1987 U.S. Field = 1/2 (.5 frame) 1. England, Holland, and West Germany. 2.
16 1738 ch15 7/30/04 932 10:31 AM Chapter 15 Page 932 Video Hardware Super VHS and Hi-8 video sources give better results, as do configurations using more than 256 colors. For the best results, use DV camcorders equipped with IEEE 1394 (i.LINK/FireWire) connectors; these can output high-quality digital video direct to your computer without the need to perform an analog-to-digital conversion.
16 1738 ch15 7/30/04 10:31 AM Page 933 Video Cards for Multimedia Chapter 15 933 playback, but they typically do not deliver the same quality or compression ratio. Following are two of the major codec algorithms: ■ JPEG (Joint Photographic Experts Group). Originally developed for still images, JPEG can compress and decompress at rates acceptable for nearly full-motion video (30fps). JPEG still uses a series of still images, which makes editing easier.
16 1738 ch15 7/30/04 934 10:31 AM Chapter 15 Page 934 Video Hardware In addition, many graphics cards with TV-in, such as ATI’s Radeon-based All-in-Wonder series and NVIDIA’s Personal Cinema FX also include PVR software. A remote control and onscreen program guide is often included to make TV viewing and recording even easier. Table 15.23 provides a breakdown of some common video cards and capture devices supporting key features.
16 1738 ch15 7/30/04 10:31 AM Page 935 Video Cards for Multimedia Table 15.24 Chapter 15 935 Multimedia Device Comparison Device Type Pros Cons Graphics card with built-in TV tuner and capture Convenience; single-slot solution Upgrading requires card replacement. TV-tuner card Allows upgrade to existing graphics cards; might be movable to newer models Might not work with all current chipsets.
16 1738 ch15 7/30/04 936 10:31 AM Chapter 15 Table 15.25 Page 936 Video Hardware Continued Device Type Problem Solutions All devices Video capture is jerky. Frame rate is too low. Increasing it might require capturing video in a smaller window; use fastest parallel port setting you can; use faster CPU and increase RAM to improve results. All devices Video playback has pauses, dropped frames.
16 1738 ch15 7/30/04 10:31 AM Page 937 Adapter and Display Troubleshooting Chapter 15 937 Servicing monitors is a slightly different proposition. Although a display often is replaced as a whole unit, some displays—particularly 20'' or larger CRTs or most LCD panels—might be cheaper to repair than to replace. If you decide to repair the monitor, your best bet is to either contact the company from which you purchased the display or contact one of the companies that specializes in monitor depot repair.
16 1738 ch15 7/30/04 938 10:31 AM Chapter 15 Page 938 Video Hardware models. Even factory service technicians often lack proper documentation and service information for newer models; they usually exchange your unit for another and repair the defective one later. Never buy a display for which no local factory repair depot is available. If you have a problem with a display or an adapter, it pays to call the manufacturer, who might know about the problem and make repairs available.
16 1738 ch15 7/30/04 10:31 AM Page 939 Adapter and Display Troubleshooting Chapter 15 939 Troubleshooting Video Cards and Drivers Problem Display works in DOS but not in Windows. Solution If you have an acceptable picture quality in MS-DOS mode (system boot) but no picture in Windows, most likely you have an incorrect or corrupted video driver installed in Windows.
16 1738 ch15 7/30/04 940 10:31 AM Chapter 15 Page 940 Video Hardware DisplayMate DisplayMate is a unique diagnostic and testing program designed to thoroughly test your video adapter and display. It is somewhat unique in that most conventional PC hardware diagnostics programs do not emphasize video testing the way this program does. I find it useful not only in testing whether a video adapter is functioning properly, but also in examining video displays.
