Video Card Inputs and Outputs
One simple but important feature to be considered in selecting a video card is the type of inputs and outputs it has. The types of inputs and outputs will determine what type of monitor and other video peripherals (video cameras, editing consoles, etc.) you can attach to your homebuilt computer.
So think ahead to what you may want to use your computer for a year or so down the road. Maybe you'll want to make videos of your family, for example.
In the recent past, almost all computers used standard SVGA analog monitors that connected via a standardized connector; and in the past, all video cards had an SVGA output.
Nowadays, the VGA-style monitor connector is slowly being replaced by DVI and HDMI connectors. In addition, an increasing number of high-end video cards come equipped with special connectors for specialized purposes. It's vital to choose a card that has the correct connectors for whatever it is you want to attach it to.
For most users, all this means is that the video card has to match the monitor. Most monitors nowadays have DVI and/or HDMI inputs, and many still have VGA inputs. Some have all three. The important thing is to make sure that the monitor you choose has the correct input to match the output of the video card that you will use.
But some users will also want outputs for DV, NTSC, S-Video, RF, HDTV, or other specialized connections, especially if they want to use their computers for video editing, VHS-to-digital conversion, watching television, or other specialized uses.
There also are "dual-head" video cards that can feed two monitors.
Some high-end video cards also are designed to allow input from video sources. These cards are used for video production, editing, capture, and many other purposes that involve transferring images from external devices onto a computer.
Some of the more popular input connectors found on video cards include:
NTSC, PAL, and SECAM. These are "old" television video standards used in various parts of the world (the United States uses NTSC). These connections combine the red, green, and blue video channels, sync pulses, and so forth into a "composite" video signal. All three of these standards are expected to fade into history as HDTV (High-Definition Television) becomes the norm.
RGB handles the video signal as separate red, green, and blue components. RGB is used primary for video processing equipment, television projectors, and professional-quality video monitors and recorders.
S-Video offers higher definition than the NTSC, PAL, or SECAM composite standards, but less definition than HDTV. Many high-end video cards offer S-Video inputs and outputs.
YPrPb is the HDTV equivalent of an S-Video connector. It allows direct connection of a video card to High-Definition televisions and other HDTV devices.
RF (Radio Frequency) inputs are used on cards that accept input from standard broadcast or cable television signals. These cards have built-in TV tuners that allow the computer to be used as a television or to be connected to VCR's, certain security cameras, and other devices that use a modulated RF output.
HDTC inputs allow High-Definition television signals to be viewed on the computer, subject to the limitations of the monitor. HDMI inputs allow video and sound to be inputted to the card.