6.5 Digitizing Video
6.5.2 Installing and configuring a video capture board
Refer to the capture card documentation, and prepare its hardware configuration jumpers (or switches) for operation. The factory default settings of the card usually work well, but the user should examine the installed devices of the system for address and IRQ conflicts.

Install the video capture card in one of the unit adapter slots. As with any other adapter card, this requires that the outer cover of the system unit be removed. Inside the unit, remove the expansion slot cover of a compatible expansion slot. Many capture cards are full-length cards, so make sure the slot can handle the physical dimension of the card. Make sure the expansion slot type is compatible with the capture card edge connector.

Connect the capture card to the VGA card as directed by the manufacturer installation guide. Some VGA cards use an edge connector built into the top of the card.

Install any antennas that must be connected to the card for the intended application. These could include a TV antenna, a coaxial cable from the television, or an FM radio antenna. Connect the video-in cables to the audio and video source(s) being used for input and the audio cable to the audio source(s). In this case, there is a stereo audio-in (left/right) provision, and two possible sources for video-in.

The audio and video connections are typically made with standard RCA cables and connectors. Connect the VGA monitor signal cable to the capture card VGA-out connector. The video signal passes through the capture card and is looped to the VGA card. This means that the screen image can be present on the monitor and the video screen simultaneously. A VGA loopback cable is connected between the capture card loopback input and the VGA card RGB-out connector.

If all the hardware and software configuration settings are correct but capture problems continue, the user must troubleshoot the video capture-related hardware. In most systems, this involves a TV signal source (such as a VCR or camcorder), the cabling, the capture card, and the video card.

Most capture card software provides a preview window that enables the user to view the video coming from the video source. If the source is visible in this window, then the video source and the video-in cabling can be eliminated as a source of problems. However, simply being able to see the video in the window does not mean that the card will capture video.

If the video is present in the window, and the video source and cabling check out, then the hardware and software configurations should be checked closely. Check the capture software setup for video buffer settings. Usual video buffer settings are D0000h, D800h, E000h, or E800h. Change the setting to one of the other possible values. Add a DEVICE= statement to the CONFIG.SYS file that corresponds to the new setting for the video buffer (for example, DEVICE=path\EMM386.EXE X=D000h-D700h). Finally, reinstall and reconfigure the capture software if problems continue.

If the signal from the video source is not present in the preview window, make certain that the video source is turned on. Check the video-in cable to make certain that it is properly connected to the video-out jack of the video source and into the correct video-source input on the capture card. Check the I/O address setup of the capture card closely, as well as its setting in the capture software. Check in the video capture software to make sure that the correct video source setting is selected. While in the software settings, check the video type selected, and make sure that it is set for the NTSC standard (in the US), or the corresponding video standard used in the country or region of operation.