Video capture is the process of converting an
analog video
Video is an electronic medium for the recording, copying
Copying is the duplication of information or an artifact based on an instance of that information or artifact, and not using the process that originally generated it. With analog f ...
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 computer resource for recording data in a computer storage device, primarily identified by its file name. Just as words can be written to paper, so can data be written to a computer file. Files can be shared with and transfe ...
s, or sent to a video display, or both.
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. 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 that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad v ...
,
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 ...
or
WiFi
Wi-Fi () is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves ...
, or stored in mass-storage memory in the device itself (e.g.,
digital video recorder
A digital video recorder (DVR) is an electronic device that records video in a digital format to a disk drive, USB flash drive, SD memory card, SSD or other local or networked mass storage device. The term includes set-top boxes with direct to d ...
).
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 or PCI-e, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X and AGP bus standards. It is the common mo ...
(Blackmagic Design
Blackmagic Design Pty Ltd. is an Australian digital cinema company and hardware manufacturer based in Port Melbourne, Victoria, Australia. It designs and manufactures broadcast and cinema hardware, most notably high-end digital-movie cameras, ...
''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 audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, ...
video capture card (Datapath VisionRGB-E2s)
ISA-Framegrabberkarte.jpg, ISA analog video
Video is an electronic medium for the recording, copying
Copying is the duplication of information or an artifact based on an instance of that information or artifact, and not using the process that originally generated it. With analog f ...
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)
See also
*
TV tuner card
A TV tuner card is a kind of television tuner that allows television signals to be received by a computer. Most TV tuners also function as video capture cards, allowing them to record television programs onto a hard disk much like the digital vi ...
s, which employ video capture circuitry to capture
broadcast television
Broadcast television systems (or terrestrial television systems outside the US and Canada) are the encoding or formatting systems for the transmission and reception of terrestrial television signals.
Analog television systems were standardized b ...
*
Frame grabber
A frame grabber is an electronic device that captures (i.e., "grabs") individual, digital still frames from an analog video signal or a digital video stream. It is usually employed as a component of a computer vision system, in which video frames ...
*
Uncompressed video
Uncompressed video is digital video that either has never been compressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video monitors, video recording devices (including general-pur ...
References
*''Convergence Culture. Where Old and New Media Collide, Buying Into American Idol'', Henry Jenkins, 2006 New York University Press.
Codecs
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