Video capture is the process of converting an

analog video Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...

signal—such as that produced by a

video camera A video camera is an optical instrument that captures videos, as opposed to a movie camera, which records images on film. Video cameras were initially developed for the television industry but have since become widely used for a variety of other ...

, DVD player, or television tuner—to

digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...

and sending it to local storage or to external circuitry. The resulting digital data are referred to as a ''digital video stream'', or more often, simply ''video stream''. Depending on the application, a video stream may be recorded as

computer file A computer file is a System resource, resource for recording Data (computing), data on a Computer data storage, computer storage device, primarily identified by its filename. Just as words can be written on paper, so too can data be written to a ...

s, 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 the

Video for Windows Video for Windows was a suite of video-playing and editing software introduced by Microsoft in 1992. A runtime version for viewing videos only was made available as a free add-on to Windows 3.1, which then became an integral component of 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.

Devices

Special electronic circuitry is required to capture video from analog video sources. At the system level this function is typically performed by a dedicated video capture device, colloquially called a capture card. Such devices typically employ integrated circuit

video decoder A video decoder is an electronic circuit, often contained within a single integrated circuit chip, that converts base-band analog video signals to digital video. Video decoders commonly allow programmable control over video characteristics such as ...

s 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 as

USB Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical ...

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

Wi-Fi Wi-Fi () is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for Wireless LAN, local area networking of devices and Internet access, allowing nearby digital devices to exchange data by ...

, or stored in mass-storage memory in the device itself (e.g.,

digital video recorder A digital video recorder (DVR), also referred to as a personal video recorder (PVR) particularly in Canadian and British English, is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SS ...

). Decklink DSCF4439 (16425904428).jpg, A dual link 3 Gb/s SDI video capture card for

PCIe PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed standard used to connect hardware components inside computers. It is designed to replace older expansion bus standards such as Peripher ...

(

Blackmagic Design Blackmagic Design Pty Ltd is an Australian digital cinema company and manufacturer based in South Melbourne, Victoria (state), Victoria, Australia. It designs and produces broadcast and cinema-grade hardware; notably, high-end digital movie ca ...

''DeckLink HD Extreme 3D'') Datapath VisionRGB-E2s Dual Port Capture Card.jpg, A PCIe 2-port

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...

video capture card (Datapath VisionRGB-E2s) ISA-Framegrabberkarte.jpg, ISA

capture card 8-channel uncompressed video+audio capture device.jpg, A Mini PCIe card that simultaneously captures 8 video and 8 audio signals (Sensoray 1012) Reddo Videosieppari.JPG, A low-cost, consumer-grade USB audio/video capture device (Reddo Videosieppari)

References

*''Convergence Culture. Where Old and New Media Collide, Buying Into American Idol'', Henry Jenkins, 2006 New York University Press. Codecs {{tv-tech-stub

Devices

See also

References