Video capture is the process of converting ananalog video signal—such as that produced by avideo camera, DVD player, or television tuner—todigital video and sending it to local storage or to external circuitry. The resulting digital data are referred to as adigital video stream, or more often, simplyvideo stream. Depending on the application, a video stream may be recorded ascomputer files, or sent to a video display, or both.
Early 16-bit ISA capture cards emerged in the early 90s. These cards were supported by VIDCAP as part of theVideo for Windows package. One early card was a sandwich of two cards as early processors needed more logic to even get up to 15 frames per second.
PCI capture cards offered 30 frames per second. These cards could also handle capturing VHS tapes etc. but VHS image quality was poor so many adopted new video cameras until eventually digital cameras surfaced. Capturing video from digital cameras delivered excellent results above DVD quality.
Special electronic circuitry is required to capture video from analog video sources. At the system level this function is typically performed by a dedicatedvideo capture device, colloquially called acapture card.[1] Such devices typically employ integrated circuitvideo decoders to convert incoming video signals to a standard digital video format, and additional circuitry to convey the resulting digital video to local storage or to circuitry outside the video capture device, or both. Depending on the device, the resulting video stream may be conveyed to external circuitry via a computer bus (e.g.,PCI/104 or PCIe) or a communication interface such asUSB,Ethernet orWi-Fi, or stored in mass-storage memory in the device itself (e.g.,digital video recorder).
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