Of all the expansion devices that have become available for PCs over the last decade, video capture and PC-TV boards (Fig. 50-1) are probably the most exciting. The ability to record sound and video on a PC has been an important element in the push toward desktop multimedia PCs. The captured data can then be edited, enhanced, and incorporated into any manner of computerized presentation. Such potential makes the video capture board ideal for applications ranging from real-estate to business to medicine. PC-TV boards bring television and Intercast broadcasts to your desktop. Not only does this open another avenue of entertainment for the PC, but it also takes another step toward the "convergence" of PC, TV, and the Internet. In many cases, a single device can play TV, capture audio and video, or playback MPEG files. This chapter introduces you to basic video recorder and PC-TV concepts, and shows you how to deal with a wide range of problems that can accompany the hardware.

The first step in dealing with video capture problems is to understand the processes that make the board work in the first place. Figure 50-2 illustrates a multi-function video board which doubles as a capture board, a VGA video adapter, and a video output system (to drive things such as a TV monitor or VCR). The capture board plugs right into any available ISA slot. Keep in mind that this is only one type of video capture product. Many of the newest video capture-type products use the PCI bus for high-performance data transfer.

The heart of the board is a microcontroller which directly operates the video decoder and image controller ICs. Video signals entering the decoder are converted to analog RGB (red, green, and blue) data. The genlock circuit is a high-frequency clock source which is phase-locked to the horizontal sync signal of the video source. The ADC (analog-to-digital converter) circuits use the "genlock" signal as a basis for digitizing the video (not all video capture products offer a genlock feature). The image controller (which can be set to operate in several different color modes such as 15-bit, 16-bit, and 24-bit modes) directs the transfer of digitized image data into image memory. Image memory can then be read from a second data bus directly to a digital multiplexer. The multiplexer selects data from either the image memory or the VGA controller to be passed on to the VGA DAC (digital-to-analog converter) where data is converted into analog form to drive the monitor. Thus, you can see the digitized video image on the monitor while it is being recorded.

The capture board also contains a standard VGA sub-system which provides a VGA video adapter for the PC on the same board. The VGA controller IC manages the video adapter operations, and stores graphic information in the VGA memory. The VGA controller can be addressed directly from the expansion bus. When the capture circuit is idle, the VGA controller passes data from the VGA memory on to the data multiplexer where it is converted to analog RGB monitor signals. Not all video capture devices include an on-board video adapter - many only capture video, and use the existing video adapter for "preview" and "playback".

The capture board in Fig. 50-2 offers an added bonus - a video drive sub-system. Video data is passed through a line buffer. The line buffer converts data to NTSC data rates, then passes the data on to a stand-alone VGA DAC. The analog RGB signals are sent to an output port, as well as processed through an S-video encoder which provides an independent video source. This is ideal for observing the VGA image on a TV, or recording it to a VCR. Figure 50-3 shows you the typical connector arrangement for such a multi-function capture board. As a technician, you should realize that only a few video capture boards provide built-in VGA adapter support or an independent video output.

Now that you have some insight into how a video capture board works, you can understand how the video capture process works in the PC as a whole. Figure 50-4 shows you a "roadmap" of audio and video data through the PC. As with all capture systems, the process begins with a video source. In today’s PCs, the source can be any S-video device such as a camcorder, VCR, or laserdisk player. Video signals are sent to the capture board, while sound is sent to the PC sound board.

The video capture board digitizes the video signal. Some boards - such as Intel's Smart Video Recorder (SVR) - will process and compress the video data "on-the-fly" (also known as hardware-based compression). Data is then stored in system RAM. Audio is digitized by the sound board, and that audio data is also placed in system RAM. Under software tools like Microsoft Video for Windows, sound and video data are synchronized together, then stored on the hard drive in a standard file format such as Audio-Video Interleave (or .AVI). While data is being moved to the hard drive, additional data compression techniques (or software-based compression) can be applied to reduce the overall resulting file size.

During the playback process, files are read from the hard drive, and expanded (if necessary with software decompression techniques) into system RAM. Sound and video data are separated. Video data is sent to the display adapter, and on to the monitor. Sound data is sent to the sound board where it is processed and passed to the speakers. Thus, sound and video can be repeated as required, or used in conjunction with other computer packages such as presentation packages.

Video capture produces a tremendous amount of data. Just consider a single 320x200 frame which is made up of 64000 pixels (320x200). If you are using a color depth of 65536 colors, each pixel would need 16 bits (2 bytes) or 128KB per frame. If you are trying to capture 10 complete frames per second, more than 1.28MB per second will have to be channeled into system RAM. As you might imagine, it would not take more than a few seconds to use up all the available RAM in a PC. However, much of the video data captured in each frame is repetitive - it can be compressed before storing data in RAM or on the hard drive, then decompressed during playback. As a result, the actual data stored in the system can be much less than it would be otherwise.

The Compressor/Decompressor (or CODEC) is responsible for reducing this data load. A well-designed CODEC can reduce data without measurable reducing the quality of an image. CODEC functions can be implemented in hardware as a digital signal processor, or in software as a driver. Today, there are four major CODEC techniques; Cinepack, Indeo, Video 1, and RLE. Cinepack is perhaps the best codec, offering very good compression for fast action sequences (where data changes rapidly) with little loss of image quality. However, Cinepack compression is a very slow process - certainly not appropriate for "on-the-fly" compression. Intel’s Indeo video is much faster than Cinepack, but is not well-suited for quickly-changing data such as that found in fast action sequences. Video 1 and RLE are generally used only for slow animation or palletized video.

Indeo video is Intel’s digital video capture, compression, and decompression software. The technology revolves around a software-based CODEC (a driver) that compresses digital video data for storage, and decompresses it for playback on a multimedia PC. In order for a computer to play files compressed with Indeo video, the Indeo video codec must be installed on the computer, using the setup program provided by Intel. You can check for the presence of Indeo video drivers using the following steps:

• Click Start, select Settings, then open the Control Panel.
• Double-click on Multimedia.
• Select the Advanced tab.
• Double-click on "Video Compression Codecs".
• Double-click on the Indeo video drivers you see listed.
• Click Settings. An "About" box appears containing the version number.

NOTE: If there are no Indeo video drivers listed, they are not installed.

Even under the best of circumstances, video capture presents a serious challenge to system processing. The challenge of video capture is to record an image of adequate quality at a window size large enough to be meaningful, while maintaining a frame rate high-enough to reproduce smooth motion. Quality video capture requires a careful balance of processing power with window size, frame rate, and original image quality. This part of the chapter outlines some issues to consider when capturing video.

It takes a finite amount of time to put a pixel on the screen - the more pixels that must be generated, the more time is required. Since larger playback windows contain more pixels, it takes more time to "draw" each playback frame. This in turn reduces the frame rate. Larger playback windows also result in larger video files. Faster machines can support larger playback windows for any given frame rate. There are typically three playback window sizes:

• 320x240 is considered ideal for many multimedia applications, but is limited to slower frame rates.
• 240x180 is regarded as a good intermediate window size across a range of frame rates.
• 160x120 is the smallest commonly used video window size, but allows the fastest frame rates.

Frame rate has a profound influence on playback quality. Faster frame rates provide smoother images (especially for moving images or action shots), but requires more data. Smaller playback windows can usually sustain a higher frame rate, and vice versa. Faster machines can support faster frame rates for any given playback window size. The most common frame rates are listed below:

• 5-10fps Used for low data rate applications like video conferencing or Internet video.
• 15fps Considered satisfactory for most multimedia presentation applications.
• 24fps The frame rate at which motion pictures are projected in theaters.
• 25fps PAL (Europe) broadcast television frame rate.
• 30fps NTSC (USA, Japan) broadcast television frame rate.

The most important factor affecting the quality of your final video capture file is the quality of the original source video. Compression cannot recreate detail that wasn’t present in the original image, but it can take artifacts present in the original video (such as static) and potentially make them worse. So it is important that the best video source possible be used to create compressed video files.

Compression algorithms (such as Indeo) analyze the digitized video input stream searching for redundant or predictable data patterns which can be compressed and reconstructed later. The CODEC compressor interprets noise or artifacts digitized from the analog source as non-redundant, unpredictable data and therefore wastes valuable CPU time and file space attempting to accurately compress and store these deficiencies. That’s why the quality of the original source video is so critical to the quality of the resulting compressed digital video file. Video artifacts can also look worse after compression than they did originally.

Capture your source video using a high-quality video tape format. The best source video uses S-Video, rather than composite formats. S-Video signals carry separate signals for luminance (brightness) and chrominance (color) - resulting in higher bandwidth and an improved signal-to-noise ratio. Composite video sources modulate the luminance and chrominance together on one signal, which lowers both the bandwidth and the signal-to-noise ratio. Composite video signals are also subject to video artifacts such as color bleeding. The available formats are outlined below:

• D1 and Digital Betacam - D1 and Digital Betacam actually store video information digitally (rather like an audio CD). Both formats are broadcast-quality but expensive even for a professional’s budget.
• D2 - D2 is the digital composite cousin of D1 and is similar to D1 in both quality and expense.
• Betacam SP - Betacam SP is the most widely used analog recording format for video creation and post-production. Its high quality makes it an ideal choice for professional and semiprofessional multimedia authoring.
• 1" Type C, ¾" U-Matic - 1" and ¾" literally refer to the width of the recording tape used in each format. 1" is an open reel-to-reel format, and ¾" is a cartridge format. Both are older professional studio formats. Both produce better results than consumer formats, but they have been almost entirely supplanted by the newer and better Betacam SP format.
• Videodisc - Despite being a composite format, videodisc (also known as "laserdisc") still provides good overall quality. Some videodisc players provide S-Video outputs, though the original signal is still composite, and low-cost electronics can sometimes make these S-Video outputs worse than the composite.
• Hi-8, Super-VHS - Hi-8 and S-VHS are consumer formats, so they’re inexpensive and easily available. Both produce good results for desktop and consumer use.
• VHS - VHS is the familiar home consumer format. Its composite signal and low-cost recording and playback mechanisms make it the lowest in quality of any available format, and is not suitable for commercial multimedia.

As with lighting, selecting colors and arranging color in a scene can effect the overall quality of your video source. Use the points below to optimize your use of color:

• Avoid saturated colors in the scene - Video with highly saturated colors (especially red) can bleed or appear blocky - particularly when viewed on 8-bit (256 color) displays.
• Avoid adjacent areas of high contrast - For example, a white shirt with black stripes is a poor choice. Sudden changes in brightness levels can emphasize color bleeding and create edges that are more difficult to compress.
• Avoid extremely thin horizontal or vertical lines - Areas of fine detail are not always particularly visible after compression, especially when displayed in a multimedia application window. Extremely fine lines or patterns (such as those that are one pixel wide) can distort the source video image. Such distortion looks bad, and is extremely difficult to compress successfully.

If you’ve ever snapped a photo, you’ve probably been concerned with lighting. Lighting is just as important with video, and can effect the overall image quality used during the capture. The following points offer some lighting tips to produce the clearest images, and minimize the noise often produced in poor lighting environments:

• Use ample light - Adequate lighting is vital for creating high-quality video. Most consumer video cameras generate noise in low light. Random noise in an image decreases the redundant information and leads to poor compressed video quality and larger image files.
• Avoid fluorescent light - The "color temperature" of fluorescent light makes videos look blue-green. If you’re in an office, shoot near windows to use the natural light. Place the camera between the windows and the subject (don’t use the windows as a background - this would place your subject in a shadow).
• Use natural light wherever possible - The best light occurs outside on a cloudy or overcast day, because the light is evenly diffused. Direct sunlight can create areas of deep shadow where video noise can be prominent.
• Use a reflector to bounce light onto your subject - Reflectors produce more even lighting and can also reduce areas of deep shadow.

The way in which you use the camera to record original video will also have a profound impact on the way in which the CODEC can compress the video during capture. The following tips can help you get the most compression potential from your camera techniques:

• Use a tripod - Even the best hand-held video camera moves, and this movement is always noticed by the viewer. Also, because a camera on a tripod is steadier, more information is redundant between frames - yielding better compression.
• Use close-ups - Remember that your video will probably be played within a relatively small window on a computer monitor. Close-ups work well to emphasize your visual message in this medium, and reduce the small detail which may be lost during compression anyway.
• Don’t overuse pans and zooms - Pans and zooms limit how much can be compressed because nearly every pixel can change between frames. Rather than zooming, break the action up into two static shots (i.e. one close-up and one long shot). Use other techniques to create visual excitement. For example, instead of centering your subject in the frame, create a more dynamic shot by placing the subject to one side of center and directing her attention to the other side of the frame.
• Use auto-focus wisely - The auto-focus feature of most modern video cameras works well for most medium and wide shots, but don’t use it in close-ups where the subject is moving, or when zooming in on a subject. The entire image gets blurry for a moment, then sharp as the camera attempts to stay focused on the object in the center of the frame. This is distracting, and it limits the effectiveness of compression because every pixel changes as the camera refocuses. Instead, lock your camera on non-auto focus, zoom in tight on the subject, then manually focus and zoom back out to frame the shot before you shoot.

Television has always been a popular medium for information, education, and entertainment. With the introduction of PC-TV boards, television programs can now be presented on your monitor directly in a window - even while you do other work such as working on a spreadsheet or in a word processor. Now that many urban and suburban areas are wired for cable service, a PC-TV board can display dozens of channels of clean, clear programming. Many PC-TV boards also provide a means of capturing still or moving images from any valid NTSC or PAL signal, so captures can take place from live television signals, or from recorded sources such as VCRs. In addition, PC-TV boards can access Intercast broadcasting (mixing Internet web content and live TV programming). This combination of features makes PC-TV boards particularly handy tools for low-end multimedia creation. A typical PC-TV board is illustrated in Fig. 50-5.

The heart of the PC-TV card is the TV Tuner. As with any ordinary TV, the tuner isolates particular channels from a cable or antenna signal source. A dbx TV-stereo decoder separates video and audio components of the channel. An audio jack provides sound from the tuned channel (and is ideal for headphones), while a CD-audio pass-through connector allows the sound to be passed through to the sound card just like CD-audio. At the same time, video data is digitized through a video digitizer IC and formatted to cross the PCI bus to the video adapter board. A set of auxiliary video and audio inputs allow the PC-TV board to play or capture signals from other video sources - such as VCRs.

To display live video on your PC monitor, many current PC-TV boards (such as Hauppague’s WinCast/TV board) use a technique called "PCI Push". With this technique, the live video is digitized by the PC-TV board itself, and is then moved over the PCI bus directly into the memory of your video display adapter. The advantage of this process is a significant reduction in processing overhead - video data does not need to be stored in main RAM. Here are the basic steps involved in getting live TV onto your video screen:

• The TV tuner is controlled by software to tune to a specified TV channel (antenna or local cable). The tuner takes a modulated television broadcast signal and turns it into demodulated video and audio signals.
• The demodulated video from the TV tuner goes directly into the video digitizer, where it is converted into a digital form using YUV 4:2:2 sampling. This is a high quality sampling scheme which results in resolution equivalent to 24-bits of RGB per video pixel (a "true color" video mode).
• The demodulated audio goes into an on-board audio switcher, which can receive audio from the TV tuner or the audio in jack. The output of this audio switcher goes to both the audio out jack and the CD-audio pass-through connector for connection to a sound card.
• The video digitizer is also a PCI mater mode device. After the video pixels are digitized, the video digitizer "pushes" them over the PCI bus into the memory of the PC’s video display adapter. It does this without requiring the processor to do any work.
• Using PC-TV software, the video adapter, receives the TV information, and displays the selected channel in a window.

Live TV can be displayed on your monitor using either "video overlay" or the "primary surface" mode (the actual mode which is used depends upon the PC’s hardware and software). If you have a video display adapter which supports Windows 95 DirectDraw, and your video adapter has a "video port" which is designed to accept digital video, and your video adapter has enough display memory to hold the digitized video image, then the PC-TV board’s video digitizer moves YUV 4:2:2 video pixels for temporary storage into an off-screen part of the video memory called a "secondary surface". This method is called "Video Overlay". The video display adapter will then convert the video image from YUV 4:2:2 into RGB video and continuously overlay the display screen with the video image. Using "Video Overlay", the video controller treats the live TV image just like any other window, which results in a 24-bit video image on your VGA screen. You will also see closed captioning on-screen and you can display full screen TV at all video resolutions.

NOTE: Video chips which can support "Video Overlay" include the S3 Trio 64V+, S3 ViRGE 3D, Cirrus Logic 5446, and ATI Rage II.

If your VGA display adapter has a DirectDraw driver but does not have either a Video Port or enough memory to hold the video image off-screen, then the PC-TV board will likely convert the YUV 4:2:2 video pixels into an RGB format which is compatible with your video display adapter’s current operating mode (8-bits per pixel, 16-bits per pixel, or 24-bits per pixel) and then moves the pixels directly into the memory (or "primary surface") of your video adapter. This results in a video image whose color depth is dependent upon your video adapter’s operating mode. For example, the TV image will not be as good when running in a 8-bit per pixel mode as when running your video system in 16-bit per pixel mode. Also, since the video is moved directly onto the primary surface, features such as close captioning and full-screen TV (in resolutions greater than 640x480) will be disabled.

NOTE: Video chips which can support "Primary Surface" mode include the S3 Trio 64, S3 Vision 968, Matrox Millenium, Matrox Mystique, and Tseng ET6000.

Intel Intercast technology is a relatively new feature for television broadcasts which merges television broadcasts with the lnternet’s World Wide Web (WWW, or simply "the web"). With the Intel Intercast, broadcasters can combine the television signal with web data that includes information such as details about the current broadcast, links to other web pages, or advertising. With a PC that has a PC-TV board (such as the WinCast/TV board), a Pentium processor, and the Intel Intercast viewer software, you can:

• Watch television
• View web pages received over the airwaves
• Connect to the Internet
• Capture video images
• Track mutual funds or stocks

With the viewer, you can get more information on programs as you’re watching them, or "surf" to other related web information available through the Intercast.

Intercast content is transmitted by a TV broadcaster in a common part of the ordinary TV signal called the Vertical Blanking Interval (or VBI). The VBI can contain up to 10 lines of Intercast content, plus one line of closed captioning data. The data consists of a series of 1s and 0s, and would show up on your TV screen (if you could see it) as a series of black and white dots on each line in the VBI. The PC-TV board digitizes the video lines in the VBI which are used for Intercast web pages (the Hauppauge WinCast/TV board used 5x oversampling to digitize the video).

Since each line in the VBI has 35 bytes of data, there are 1400 samples per line. This digitizing is very similar to the digitizing used for TV video, but instead of using the PCI bus to moved digitized video into VGA display memory, the PC-TV board moves the digitized lines from the VBI into main system memory. Once in system RAM, your processor can take the digitized line and extract the Intercast content. The method of extracting the 35 bytes of Intercast content in each VBI line uses such techniques as noise reduction and echo cancellation to extract valid Intercast content (even when given a noisy TV signal). Intel’s Intercast viewer then displays the data in the Intercast viewer window.

Like most other expansion boards, video capture products generally make use of highly-integrated, proprietary ICs. As a result, it can be extremely difficult to troubleshoot the capture board to the component level. Fortunately, there are a large number of capture problems that can be tracked to installation, setup, and operational errors. When the use of diagnostics allow problems to be isolated to the capture board itself, it is a simple matter to replace the capture board outright.

Hardware conflicts are much more prevalent in today’s systems than in systems only a few years ago. Sound boards, CD-ROM interfaces, modems, drive controllers, network interface cards (NICs), and video capture boards all contribute to the congestion that fills up a system and demands its available resources. Most devices require an interrupt (IRQ), one or more I/O address settings, an occasional direct memory access (DMA) channel, and possibly some small amount of memory for a BIOS. Unfortunately, those resources are scarce in most PCs, and you must be aware of what resources are available and what is being used before adding new devices to your system. When configuring a system from scratch, it is a simple matter to make a written record of each device setting. But with so many new upgrade options, keeping a written list up to date can be a difficult effort. The use of Plug-and-Play also makes "presetting" a device’s resources difficult. As a technician servicing and upgrading customer's systems, you will rarely have the luxury to perform such a thorough analysis. Your most effective course is to use a diagnostic tool such as Microsoft's MSD, or a hardware tool like the Discovery Card by AllMicro to quickly check your system and report on the resources being used.

All CPUs operate linearly - that is, they only tackle one task at a time. When a device such as the keyboard needs the CPU to perform important work that can not wait for free CPU time, an interrupt signal is generated which forces the CPU to put aside whatever it was doing and respond to the interrupt immediately. When the device requesting the interrupt has been taken care of, the CPU can return to whatever it was doing until the next interrupt comes along. The problem is that only ONE device can use any one interrupt. If two or more devices try to use the same interrupt at the same time, one of those conflicting devices will not operate properly. In mild cases, this may appear simply as system hesitation. In serious cases, IRQ conflicts can crash your system. When you find that more than one device is using an interrupt, you must place one of those conflicting devices on an unused IRQ. IRQs can usually be changed by altering a jumper or DIP switch on the expansion board. You can recognize the effects of IRQ conflicts between a video capture board and other devices in your system from the following symptoms:

• Video frames are dropped during video capture or playback.
• The video capture or playback process is slow or jumpy.
• The system hesitates or hangs up (crashes) completely.
• The display or data file generated during capture is corrupt.
• Audio is not captured or played back properly (if at all).

An I/O address works a bit differently. Most devices require one or more addresses to exchange data and instructions between its "registers" and the system. This I/O address works in conjunction with an IRQ, although an IRQ can be changed without changing the I/O address. All devices must use a unique I/O address. Otherwise, one device may try writing data while another device tries to read data, and the operation of both devices will be effected. I/O conflicts may also result in system crashes. Like IRQs, it is important that each device be assigned to its own unique I/O address. If more than one address is needed, there can be NO overlap of addresses at all. When more than one device attempts to use the same address(es), you must move one of the devices to an unused area. I/O settings can usually be changed by altering hardware jumpers or DIP switch settings on the expansion board. You can recognize the effects of I/O conflicts between a video capture board and other devices in your system from the following symptoms:

• The video capture board installation program or device driver refuses to recognize or initialize the capture board.
• Microsoft Video for Windows (or other capture application) can’t initialize the capture device.
• The video capture board works erratically, or fails to respond at all.

Although video capture and playback devices can sometimes be daunting, there is a series of fairly "standard" troubleshooting policies that can help you track down potential problem areas quickly:

• Use the latest drivers. Video capture, MPEG, and PC-TV devices depend on drivers. Buggy or outdated drivers can easily result in errors and poor performance.
• Run in the 8-bit (256 color) graphics mode. Running in any "lower" mode will result in extremely poor image quality. If you have sufficient video memory and PC processing power, you should run in the 16-bit (high color) video mode.
• Use care in the installation of drivers - especially with PC-TV drivers which depend on DirectDraw and ActiveX resources under Windows 95. You may need to update or reinstall these resources after the device is installed.
• Be sure to use a strong and clean signal for recording. Your capture is only as good as the original signal.
• Be sure to use good-quality cabling. Poor cabling and connectors can easily degrade even strong video signals. Check that all of your video/audio cables are secure.
• When using MPEG and PC-TV devices, use moderate video resolutions and refresh rates. These devices normally "downshift" higher refresh rates during play, and the flicker can be quite noticeable at high resolutions.
• Don’t shift video modes while MPEG or PC-TV devices are in use. The change in the video drivers can crash the computer.
• Disable power management features such as APM when using video capture, MPEG, and playback devices. The computer can crash if the system shuts down into suspend mode while these devices are in operation.
• PCI Video devices often depend on the correct configuration of a PCI bus slot. Check the slot’s configuration under your CMOS Setup.

Symptom 50-1. There are problems installing the S-Video cable. Most video capture boards are designed to accept composite audio/video signals from either a single RCA connector or an S-Video connector. Unfortunately, the S-Video connector is not keyed to prevent incorrect insertion. This generally means that signals will not reach the capture board. It is possible to install the S-Video cable rotated 90 degrees from where it should be. Make sure that the arrow on the cable matches the marking on the capture board.

Symptom 50-2. Even though a valid video source is available, you see vertical multi-colored lines appearing in the capture application window. This is a problem particular to capture boards when the board itself is loose or installed improperly, or the signal cabling is not secure. Check the capture board to see that it is fully inserted in the expansion slot. If there are any modules or sub-boards attached to the capture board, see that they are secure and inserted properly. Also check any connectors and cables to be sure that they are all installed correctly.

Symptom 50-3. Even though a valid video source is available, you see nothing but black in the capture application window. There are several possible reasons for this symptom. First, check the video signal being fed to the capture board. If there is no signal, the video capture window (i.e. the Video for Windows VIDCAP window) will be dark. You can test the video signal by disconnecting the video cable from the capture board and connecting it to a stand-alone monitor such as a TV set. Damaged or defective video cables and connectors should be replaced. If you are using a camcorder as a real-time video source, make sure that the camera is turned on, the lens cover is off, and that you have selected the correct video source (i.e. composite or S-Video). Also check that the capture board is inserted in the system properly and completely. Any sub-modules should be attached securely to the main expansion board.

Finally, there may be an IRQ conflict between your video capture board and another device in your system. If you attempt to capture a video file while the capture window is dark, and receive an error such as "Wave input device not responding", there is almost certainly an IRQ problem. Run a diagnostic such as Microsoft’s MSD (or use a hardware tool such as AllMicro’s Discovery Card) to identify unused IRQs, then set the video capture board to use an available IRQ. In some cases, you must run an installation routine for the capture board when changing settings. If problems persist, the capture board may have failed.

Symptom 50-4. During installation, you see the error; "Unable to locate an available interrupt". This type of symptom occurs with an IRQ conflict, or when a device driver or TSR interferes with the installation. Make sure that the capture board is configured to use an available IRQ (i.e. 9, 10, 11, or 12). You may have to use a diagnostic (such as Microsoft's MSD or the Discovery Card by AllMicro) to locate available interrupts. Try booting the system from a clean DOS disk to prevent any TSRs or device drivers from interfering with installation.

Unfortunately, if there is a conflict during installation, there will also probably be conflicts during actual use. So, if you suspect a TSR or device driver conflict, you will have to disable TSRs and device drivers one-by-one until the conflict disappears, then work with the offending TSR or device driver configuration to eliminate the conflict.

Symptom 50-5. You cannot initialize the capture board due to a lack of available IRQs. On some systems, the capture board fails to initialize when launching the capture application. This is usually due to the lack of an available interrupt request (IRQ) for the capture board to use. To check the IRQs on your system:

1. Go to the Windows 95 desktop.
1. Right-click the My Computer icon and select Properties.
1. Click the Device Manager tab.
1. Double-click on "Computer" to display all IRQ resources.

You see each of your system’s interrupts, and which devices are using them. If all IRQs are already assigned to other devices, you’ll need to free an IRQ for the video capture board. You can usually free an IRQ by removing a device no longer in use, or disable the IRQ on a feature not being used (i.e. if you’re not using the MIDI port of a sound board, disable it to free the IRQ).

Symptom 50-6. When starting the capture utility, you see the error; "Unable to initialize a capture device". This is an error message produced by the capture utility (i.e. the Video for Windows VIDCAP utility) when the capture board can not be located. For most capture boards, there is probably an IRQ conflict with one or more devices in the system - this can occur easily when new devices are added to the system after the capture board has been installed. Use a diagnostic (such as Microsoft's MSD or the Discovery Card by AllMicro) to locate unused IRQs. If new equipment has been added, change the new equipment to relieve the conflict. If the error manifested itself when the capture board was installed, change the board's IRQ to an available setting.

If interrupts check out properly, make sure the capture board is inserted properly and completely into the motherboard. If there are any modules or sub-boards attached to the capture board, see that they are inserted and secured properly. You may also have installed the capture software in the wrong order. Some boards require that DOS software be installed first, then Windows software drivers must be installed. If this process is reversed, the capture board’s Windows drivers may not install properly. Try reinstalling the capture software. If software is correct, try another capture board.

Symptom 50-7. Colors appear washed out or bleeding. This can occur while viewing the video image before capture, or during the actual playback of an image file. If the problem is manifesting itself before capture, begin by checking the signal quality from your video source such as a VCR or video camera. A loose or damaged cable, or poor-quality video source can result in signal degradation at the video capture board.

If the video signal and connections are intact (and the signal looks good on a monitor such as a TV set), the problem may be in the Windows video driver being used. Better color depth in the video driver will result in better color quality in the video capture. In virtually all cases, a 16 color video driver (generic VGA) is totally inappropriate for video capture applications - a 256 color driver is considered to be the minimum. If you are already using a 256 color video driver, try an upgrade to a 32K, 64K, or 16M color driver. You may have to contact the manufacturer of the particular video board to obtain an advanced video driver for Windows 3.1x or Windows 95.

Symptom 50-8. The video signal appears to be weak or washed out even though the video signal source is acceptable. This is typical when a composite video signal output is being sent to the video capture board as well as to a stand-alone monitor through a Y-connector. Composite output signals are usually power balanced for ONE connection load ONLY. When the load on a composite output is not balanced properly, the video signal at your capture board will not contain enough power (signal degradation will occur). Try connecting the video signal directly to the video capture board.

Symptom 50-9. You get a "Vertical Sync" error when trying to capture. Chances are that you’ve got an IRQ conflict. Check the IRQ assigned to the video card’s PCI slot in the Device Manager under Windows 95. If this PCI slot the video card is in is being used by another device, you will need to reassign the PCI slot for the video board a different IRQ. This can be done through your system’s CMOS Setup. If no IRQ is being assigned to the PCI slot the video card is in, that can also be a problem. Once again, you can assign an IRQ to the PCI slot through the CMOS Setup. There could also be an IRQ conflict with the video capture driver. To check this, look in the Control Panel under Multimedia. Click on the Advanced tab and then look under Video Capture Drivers. There you’ll see an entry such as "Diamond Multimedia Capture Driver". Double-click on it and then click on the Settings option. There you can change the IRQ of the capture driver. Try a free IRQ, or free an IRQ.

Symptom 50-10. Up to 50% of small frames are being dropped (large frames appear to capture properly). This symptom may occur in systems using fast 32-bit SCSI adapter boards, and is almost always due to the effects of double buffering in the SMARTDRV.EXE utility. If possible, try to disable SmartDrive in the CONFIG.SYS file. If SmartDrive cannot be disabled (usually because it would have adverse side-effects on other devices which rely on SmartDrive’s caching), try capturing video at a larger frame size such as 320x240 before capturing at a small frame size. This lets SmartDrive adjust to the data needs of the larger frame size, so subsequent captures at a smaller frame size should work correctly until the system is rebooted. An updated video capture driver may also provide better performance.

Symptom 50-11. When capturing video, the corresponding screen image appears broken-up or jerky. If the image being previewed on the screen prior to capture looks smooth and the captured video looks smooth when played back, you should suspect that the customer’s hardware platform is not quite fast enough to update the screen while capturing. This is not necessarily a problem, since many video capture applications (i.e. Video for Windows) is designed to sacrifice screen updates for the sake of smooth captures. If you need a smooth display during capture, start by relieving any unnecessary processing loads from the system:

• close other Windows 95 applications running in the background.
• close any DOS applications running through a window.
• make sure the Windows disk cache is set to at least 2MB (4MB if possible).
• set audio capture specifications to 8-bit, mono, 11kHz sample frequency for the lowest audio processing overhead.

Symptom 50-12. The video capture board is working, but captures are occurring very slowly. In most cases, very slow recording performance is caused as the result of an IRQ conflict between the capture board and another device on the system. Evaluate the components in your system or run a diagnostic (such as Microsoft's MSD) to locate and identify any unused interrupts in your system. If you are faced with a jumper-only capture board, set the jumper(s) to use a free valid IRQ. If your capture board requires a software setup, run its setup utility and choose another valid interrupt (i.e. 9, 10, 11, or 15).

Symptom 50-13. You find that you cannot use the Super Compressor option in Video for Windows. This is not an actual user problem. The Super Compressor is an off-line compression utility that compresses and stores video files captured at 320x240, 15 frames per second (fps) at the same data rate as CD-ROM (150KB/sec). Video for Windows version 1.0 does not support the Super Compressor function when used with Indeo 3.0 device drivers. Only the Quick Compressor in the VIDEDIT utility is available. Later versions of Video for Windows make use of this function, and you should upgrade your version of Video for Windows at your earliest convenience.

Symptom 50-14. You can’t capture more than one frame of motion video. This is a problem reported with the Intel SVR III. While trying to capture video, the capture process stops after one frame, but the capture application acts as if it is still capturing and you must click Stop to exit. The YUV9 video format always seems to exhibit this problem. The RGB24 video format seems to work at lower window sizes. There are no problems capturing still images or sequences of still images. This problem appears to be related to an improper or incomplete installation of Windows 95 Direct Draw drivers. You can download and install the latest DirectX drivers from Microsoft’s website at: http://www.microsoft.com/directx/default.asp.

Symptom 50-15. The color video being captured is shown as black and white. There are two possible causes for this. First, the capture window (i.e. the Video for Windows VIDCAP utility) is set to receive a Composite video source, but the video signal being fed to the capture board through its S-Video cable. Check the configuration settings under your video capture options. Make sure that the correct input type (Composite or S-Video) is selected in the video capture utility.

Another possible source of problems is a bad connection. Check that the video signal is indeed color, and that a good cable is securely attached to the capture board. Try a different video source. Next, check that the capture board is inserted properly and completely in the expansion slot. If there are any modules or sub-boards attached to the capture board, see that they are secured correctly. If problems persist, try another capture board.

Symptom 50-16. The video image shown in the VIDCAP capture window appears torn or bent at the top. This symptom is typical of signals being supplied by VCRs (or camcorders used as VCRs), and is almost always the result of a weak video synchronization signal from the signal source. The problem can often be rectified by using a different (stronger) signal source (i.e. another camcorder or VCR). If you are using a VCR signal source, make sure that the Video for Windows "VCR" box is checked.

Use the S-Video signal source if possible, since S-Video signals are less prone to noise and losses than composite signals. Also make sure that the video cable feeding your capture board is not lying parallel to power cables since the power cable can induce unwanted noise into the video signal. Try placing the video capture board in another expansion slot as far as possible from the system power supply and other expansion boards since electrical signals generated by other boards may cause interference with the video data. As a sanity check, make sure that any modules or sub-boards for the video capture device are attached properly.

Symptom 50-17. When capturing video, you get an error; "No frames captured. Confirm that vertical sync interrupts are configured and enabled". There are some known issues with the Intel SVR III, but these may also effect other capture devices:

• The Adaptec 1542B & 1542C 16-Bit ISA SCSI controllers were tested with the SVR III using IRQ 11 and I/O address 330h. When the SVR III was also set to IRQ 11, the VidCap utility in Video for Windows returned blank video, and no frames were captured, then returned the error message. Reconfigure the system devices to avoid IRQ conflicts.
• The Media Vision Pro Audio Spectrum 16 16-bit sound board was tested with the SVR III using IRQ 5, IRQ 15, and I/O addresses 220h and 388h. When the SVR III and the Pro Audio Spectrum 16 were both set to IRQ 11, the SVR III software detected a conflict, and Video for Windows returned the error message. Reconfigure the system devices to avoid IRQ conflicts.
• This fault can also be caused by a Diamond VLB Speedstar Pro Video board using IRQ 2 by default. Disable the use of IRQ 2 on the Diamond Video Board.
• SiS FI2 P54C motherboards using an Award BIOS also have been known to suffer this problem. You’ll need to go into BIOS and tweak the chipset configuration. Change the "ISA BUS Clk Frequency" entry from "PCI Clk divided by 3" to "PCI Clk divided by 4".

NOTE: This changes numerous settings in the chipset configuration; i.e. SRAM, Read Pulse, SRAM Burst, Refresh, all of which go to slower value.

Symptom 50-18. You see artifacts when capturing video at high data rates. When capturing at high data rates (such as when using 640 x 480 resolutions and 30 fps frame rates), occasional problems have been noted on some PCs - most notably with Intel SVR III or Pro capture products. "Artifacts" which resemble black horizontal lines may appear in your preview or capture window. Try repeating the capture (best if the problem only occurs infrequently). If the artifacts occur too frequently for you to recapture, you’re probably trying to capture at too high a data rate for your computer’s PCI bus to handle. Reduce PCI bus traffic by lowering the data rate of the video you're capturing:

• Use a lower frame rate.
• Use a lower window resolution.
• If you’re using RGB24 as the Video Format try using YUV9 instead.
• Use more compression (a lower-quality setting).
• Turn off the preview mode.

If you continue to find horizontal black lines in both preview and captured video (even at 320x240 resolution) when using the YUV9 Video Format, your computer’s PCI chipset may be programmed to disable a featured called "host memory write posting". When enabled, this feature allows your PCI chipset to write to memory at its maximum speed. When write posting is disabled, your PCI bus performance can be significantly reduced. Write posting is enabled in different ways on different systems. Some computers may permit this feature to be controlled through the CMOS Setup, while other computers may require a BIOS upgrade from the system manufacturer.

Symptom 50-19. You see artifacts when capturing video using certain PCI graphics cards. The method used by some graphics cards and their drivers to utilize the PCI bus can sometimes cause horizontal line artifacts. For example, Intel has verified a problem using the Number Nine 9FX Motion 771 graphics card (which uses the S3 Vision968 graphics chipset) together with the SVR III. The following problems seem to occur when the display color depth is 16-bit or 32-bit, and when "preview" is on during the capture process. This also seems to occur in files captured at 320x240 resolution at 15 fps using either the YUV9 or RGB24 video format. Try setting the graphics display to 8-bit (256-color) mode (this has no effect on the quality of the captured video - only the previewed video). You might also try disabling "preview" during the capture process.

Symptom 50-20. Systems with SiS 5596 or 5511 PCI chipsets lock up when using a video capture device. This is a known issue with the Video Logic Captivator PCI board. SiS has identified the problem, and a fix is available through a BIOS update. Contact the system maker or motherboard manufacturer for a BIOS update.

Symptom 50-21. Systems lockup when running video capture devices on PCs with Phoenix BIOS. Some PCs are known to lock up with the Video Logic Captivator PCI card installed (such as members of the DEC Venturis family). This has been traced to a problem to the Phoenix v.1.6 BIOS. All PCs using Phoenix v.1.6 BIOS should be upgraded to Phoenix BIOS v.1.9 or later.

Symptom 50-22. You cannot use the capture device on a system with a SiS PCI chipset. This is a known problem with the Intel SVR III, and is due to a driver compatibility issue. The SVR III driver 1.2 will cause the system to lock up when launching the capture utility. You can determine the current driver version by opening the README.TXT file on the SVR III CD-ROM. Download and install the version 1.3 driver or later (SVR3-14.EXE from Intel at www.intel.com). You can find out which PCI chipset is in your system by checking the PCI chipset in the Device Manager:

• Click Start, Settings, and Control Panel.
• Double-click the System icon.
• Go to the Device Manager tab.
• Click the + in front of System Devices, and look for a reference to the "PCI to ISA bridge" as in Fig. 50-6

Symptom 50-23. You cannot use the capture device on a system with an S3 chipset-based video card. If your system uses; an Award BIOS version 4.51pg, Windows 95 Release 2 (OSR2), and an S3 968 based video graphics card, you may experience system lockups when trying to launch your capture program. This is a known problem which has been seen with the Intel SVR III and the Diamond Stealth 64, as well as the Number Nine Motion 771). This problem arises from a memory address conflict between the Intel SVR III and the S3-based video graphics card. According to Intel, it appears that the S3 only requests 32MB of virtual memory, rather than the 64MB it actually requires. If the BIOS allocates the memory for the capture device (such as the SVR III) right above the S3 board’s range, the system will lockup. To correct this problem, you’ll need to change the memory address range used by the video capture device:

• Open the Device Manager and double-click on the capture device (i.e. the Intel Smart Video Recorder III). Ignore the exclamation point next to it, if it has one.
• Click on the Resources tab, then un-check the box titled "Use Automatic Settings".
• Double-click on the memory range and enter an address of FFFBF000 - FFFBFFFF (the spaces on each side of the "-" symbol are needed). Click on OK.
• If Windows 95 returns the message; "The setting you have chosen conflicts with another device", click on NO, then scroll with the up and down arrows next to the address range until no conflict is noted. Click on OK.

NOTE: This device conflict is NOT apparent in Device Manager.

NOTE: Some installations have also noted that reinstalling Windows 95a or installing a video graphics card NOT based on the S3 968 chipset may also correct this problem.

Symptom 50-24. There is a gray background in the live video window display. This sometimes happens with the Video Logic Captivator family. There are some PCs that have a problem displaying live video using Captivator Pro/TV and instead show a gray background. If the window is moved around or covered by another window, then the Windows background may show through - it’s as though the live video is "transparent". Verify that all cabling and software for the video/MPEG device is installed properly.

PCs using the VIA VT481/495 chipset on the motherboard are known to have this problem (such as the Unisys MPI46664-540 model 486/66MHz). The problem is due to non-standard ISA bus timing used by the motherboard, so sending data to the video/MPEG device (i.e. the Captivator Pro/TV) registers results in the card being reset by accident. There is no known workaround or patch except to use a different video/MPEG device.

Symptom 50-25. The video device locks up in 8-bit (256 color) display modes. This problem is known to occur with Prolab VideoWorks, but can also occur with other video/MPEG devices. You might experience system lock-ups on PCs when displaying live video in 8-bit display modes with DirectX 5 installed. This problem occurs only with graphics cards that use color keying rather than hardware overlay to display live video (for example S3 Vision 968 based graphics cards). The only known workaround at this time is to run in a 16-bit display mode.

Symptom 50-26. You can’t import bitmap or still image files into the Intel DVP 4.0 application. If you can import .WAV and .AVI files, but can’t import .BMP and other static image files, there are three files you need to move from the DVP 4.0 directory to the \Windows\System directory. The names of the files are; DSEQFI40.DLL, TGAFIL40.DLL, and FLIFIL40.DLL. These .DLL files are copied to the DVP 4.0 directory by the DVP 4.0 setup program, and in very rare cases, the location of the files results in the error; "Can't import this media type" when trying to import single image file formats. Manually moving these .DLL files to the \Windows\System directory should fix the problem.

Symptom 50-27. You can’t start the Intercast viewer. If the viewer can’t detect a valid signal source, it tries to locate a valid signal source. If a valid signal exists, the software asks if you want to make it permanent. Click OK to make the setting permanent, or click No to repeat the same process the next time you run the program. If no valid signal exists, an error message appears and the software shuts down. To correct the problem, ensure that the cable or antenna connection to the PC-TV card is secure, and have the local cable company check the signal quality.

Symptom 50-28. You only receive incomplete Intercast broadcast web page displays on the PC-TV card. This happens most often when you change channels quickly - you might interrupt the reception of "billboards" and web pages sent by the broadcaster. In those instances, the default billboard or a partial web page might display. Make sure you remain on any given channel for a few minutes to allow enough time to receive complete web pages or billboards.

Symptom 50-29. You encounter missing Intercast broadcast web pages. When tuned to a channel that broadcasts Intercast content, the Intercast channel indicator animates. If no web page displays (even with the animated channel indicator), be sure you are not actively browsing (using the web browser). Double-click the desired web page title or icon in the Media Library. The broadcaster may send many web pages connected by hypertext links before signaling the main web page to display. If part or all of the pages are missing, you can still view the existing pages through the Media Library. Unless the broadcaster re-sends