An expansion card for a computer (usually a
PCI card), which allows a computer to receive and process
television and other
video signals. Some TV tuner cards also allow for reception of
FM radio.
Combined with the proper drivers and TV Tuner or VCR software, you can watch TV while you work on your computer. It can be run full screen, or in a small window to place in the corner of the screen.
VCR software (such as iuVCR or PowerVCR) allows the computer to be programmed to record television programs at specific times. This software also allows the video stream to be encoded to formats such as MPEG or DivX. These files can then be (usually illegally) re-distrubted over the Internet.