Digital video is a type of video recording system that works by using a digital rather than an analog video signal. Video is the technology of electronically capturing, Recording, processing storing transmitting and reconstructing a sequence of Still images A digital system uses discrete (discontinuous values usually but not always Symbolized Numerically (hence called "digital" to represent information for An analog or analogue signal is any continuous signal for which the time varying feature (variable of the signal is a representation of some other The terms camera, video camera, and camcorder are used interchangeably in this article.

Contents 1 History 2 Technical overview 3 Interfaces and cables 4 Storage formats 4.1 Encoding 4.2 Tapes 4.3 Discs 5 See also 6 External links

History

Starting in the late 70s to the early 80s, several types of video production equipment- such as time base correctors (TBC) and digital video effects (DVE) units (two of the latter being the Ampex ADO, and the NEC DVE)- were introduced that operated by taking a standard analog video input and digitizing it internally. Time base correction is a technique to reduce or eliminate errors caused by mechanical instability present in Analog recordings on mechanical media is a Japanese multinational IT company headquartered in Minato Tokyo, Japan. This made it easier to either correct or enhance the video signal, as in the case of a TBC, or to manipulate and add effects to the video, in the case of a DVE unit. The digitized and processed video from these units would then be converted back to standard analog video.

Later on in the 1970s, manufacturers of professional video broadcast equipment, such as Bosch (through their Fernseh division), RCA, and Ampex developed prototype digital videotape recorders in their research and development labs. Robert Bosch GmbH is a German diversified technology-based corporation which was started in 1886 by Robert Bosch in Stuttgart Germany. The Fernseh AG Television company was registered in Berlin on July 3, 1929 by John Logie RCA Corporation, founded as Radio Corporation of America, was an electronics company in existence from 1919 to 1986 Ampex ( is an American electronics company founded in 1944 by Alexander M The phrase research and development (also R and D or more often R&D) according to the Organization for Economic Co-operation and Development, refers Bosch's machine used a modified 1" Type B transport, and recorded an early form of CCIR 601 digital video. 1 inch type B VTR (designated Type B by SMPTE) is an open-reel videotape format developed by the Bosch Fernseh devision of Bosch in Germany in ITU-R Recommendation BT601, more commonly know by the abbreviations Rec None of these machines from these manufacturers were ever marketed commercially, however.

Digital video was first introduced commercially in 1986 with the Sony D-1 format, which recorded an uncompressed standard definition component video signal in digital form instead of the high-band analog forms that had been commonplace until then. is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with This article is about analog component video for the processing of color components in digital video see Digital video, Chroma subsampling and YCbCr Due to the expense, D-1 was used primarily by large television networks. A television network is a distribution network for Television content whereby a central operation provides programming for many Television stations It would eventually be replaced by cheaper systems using compressed data, most notably Sony's Digital Betacam, still heavily used as a field recording format by professional television producers. Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards

Consumer digital video first appeared in the form of QuickTime, Apple Computer's architecture for time-based and streaming data formats, which appeared in crude form around 1990. QuickTime is a Multimedia framework developed by Apple Inc, capable of handling various formats of Digital video, Media clips sound text Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics Initial consumer-level content creation tools were crude, requiring an analog video source to be digitized to a computer-readable format. While low-quality at first, consumer digital video increased rapidly in quality, first with the introduction of playback standards such as MPEG-1 and MPEG-2 (adopted for use in television transmission and DVD media), and then the introduction of the DV tape format allowing recording direct to digital data and simplifying the editing process, allowing non-linear editing systems to be deployed wholly on desktop computers. MPEG-1 was an early Standard for Lossy compression of Video and audio. MPEG-2 is a standard for "the generic coding of moving pictures and associated audio information" DVD (also known as " Digital Versatile Disc " or " Digital Video Disc " - see Etymology)is Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor "NLE" redirects here For the standardized test see National Latin Examination.

The latest development in the consumer digital video space is an Indian standard called HDVSL which is supported by the Indian Government and is likely to witness large scale commercial rollout in 2008. HDVSL stands for High Definition Video over Subscriber Line. HDVSL is an Indian standard which has been specifically developed to address the need for a terminal free computing HDVSL works on a fundamentally different paradigm wherein the video is delivered as a push video digital stream in H. HDVSL stands for High Definition Video over Subscriber Line. HDVSL is an Indian standard which has been specifically developed to address the need for a terminal free computing 264 format independent of the two way data stream but on the same pipe. The standard in effect creates two data inpaths and one data outpath. The first data inpath and outpath are traditional data streams, typically ethernet or IP. The second data inpath carries a one way digital video stream with H. 264 coding and typically originates from an edge server in the network. Since the video is not hauled over the internet but stabilised and often buffered at an edge server - it offers a significantly superior view experience, esp with HD content. Bottom of the pyramid subscribers only require a single SoC solution which decodes the video stream. The return path maybe through a mobile phone. Using HDVSL based systems, villagers in remote area are able to telephone a call centre operator who for example may find a video clip for them on Youtube which is then played on the television for the villager to view. This way there is no need for computer literacy or even basic literacy or for a computer in the home.

Technical overview

Digital video cameras come in two different image capture formats: interlaced and progressive scan. For the method of incrementally displaying Raster graphics, see Interlace (bitmaps. Progressive or noninterlaced scanning is a method for displaying storing or transmitting Moving images in which all the lines of each frame are drawn in Interlaced cameras record the image in alternating sets of lines: the odd-numbered lines are scanned, and then the even-numbered lines are scanned, then the odd-numbered lines are scanned again, and so on. One set of odd or even lines is referred to as a "field", and a consecutive pairing of two fields of opposite parity is called a frame.

A progressive scanning digital video camera records each frame as distinct, with both fields being identical. Thus, interlaced video captures twice as many fields per second as progressive video does when both operate at the same number of frames per second. Frame rate, or frame frequency, is the measurement of the Frequency (rate at which an imaging device produces unique consecutive images called frames The This is one of the reasons video has a “hyper-real” look, because it draws a different image 60 times per second, as opposed to film, which records 24 or 25 progressive frames per second.

Progressive scan camcorders such as the Panasonic DVX100 are generally more desirable because of the similarities they share with film. The Panasonic AG-DVX100 was the first affordable digital Progressive scan Camcorder. They both record frames progressively, which results in a crisper image. They can both shoot at 24 frames per second, which results in motion strobing (blurring of the subject when fast movement occurs). Thus, progressive scanning video cameras tend to be more expensive than their interlaced counterparts. (Note that even though the digital video format only allows for 29. 97 interlaced frames per second [or 25 for PAL], 24 frames per second progressive video is possible by displaying identical fields for each frame, and displaying 3 fields of an identical image for certain frames. For a more detailed explanation, see the adamwilt.com link. )

Standard film stocks such as 16 mm and 35 mm record at 24 or 25 frames per second. This focuses on Motion picture film For Still photography film see Photographic film. 35 mm film is the basic Film gauge most commonly used for both still Photography and Motion pictures, and remains relatively unchanged since its Frame rate, or frame frequency, is the measurement of the Frequency (rate at which an imaging device produces unique consecutive images called frames The For video, there are two frame rate standards: NTSC, and PAL, which shoot at 30/1. NTSC ( National Television System Committee) is the Analog television system used in the United States, Canada, Japan, Mexico PAL, short for Phase Alternating Line, is a colour -encoding system used in Broadcast television systems in large parts of the world 001 (about 29. 97) frames per second and 25 frames per second, respectively.

Digital video can be copied with no degradation in quality. No matter how many generations a digital source is copied, it will be as clear as the original first generation of digital footage.

Digital video can be processed and edited on an NLE, or non-linear editing station, a device built exclusively to edit video and audio. "NLE" redirects here For the standardized test see National Latin Examination. These frequently can import from analog as well as digital sources, but are not intended to do anything other than edit videos. Digital video can also be edited on a personal computer which has the proper hardware and software. Using an NLE station, digital video can be manipulated to follow an order, or sequence, of video clips. Avid's software and hardware is almost synonymous with the professional NLE market, but Apple’s Final Cut Pro, Adobe Premiere, Sony Vegas and similar programs are also popular. Avid Technology Inc ( is an American company specializing in video and audio production technology specifically digital non-linear editing (NLE Final Cut Pro is a professional Non-linear editing software application developed by Apple Inc Adobe Premiere Pro is a Real-time, timeline based Video editing software application Sony Vegas is a Non-linear editing system originally published by Sonic Foundry, now owned and run by Sony Creative Software

More and more, videos are edited on readily available, increasingly affordable hardware and software. Even large budget films, such as Cold Mountain, have been edited entirely on Final Cut Pro, Apple's non linear editing software. Cold Mountain is a 2003 film written and directed by Anthony Minghella, and stars Jude Law, Nicole Kidman, Renée Zellweger,

Regardless of software, digital video is generally edited on a setup with ample disk space. Digital video applied with standard DV/DVCPRO compression takes up about 250 megabytes per minute or 13 gigabytes per hour.

Digital video has a significantly lower cost than 35 mm film, as the digital tapes can be erased and re-recorded multiple times, viewed on location without processing, and the tape stock itself is very inexpensive (about $3 for a 60 minute MiniDV tape, in bulk, as of December, 2005). By comparison, 35 mm film stock costs about $1000 per minute, including processing.

Digital video is used outside of movie making. Digital television (including higher quality HDTV) started to spread in most developed countries in early 2000s. Digital television (DTV is the sending and receiving of moving images and sound by discrete ( digital) signals in contrast to the analog signals used by High-definition television (HDTV is a Digital television Broadcasting system with higher resolution than traditional television systems (standard-definition Digital video is also used in modern mobile phones and video conferencing systems. A videoconference (also known as a videoteleconference) is a set of interactive Telecommunication technologies which allow two or more locations to interact Digital video is also used for Internet distribution of media, including streaming video and peer-to-peer movie distribution. The Internet is a global system of interconnected Computer networks Streaming multimedia is Multimedia that is constantly received by and normally presented to an end-user while it is being delivered by a streaming provider (the For other uses of the term see Peer-to-peer (disambiguation For peer-to-peer networks used for file sharing see File sharing

Many types of video compression exist for serving digital video over the internet, and onto DVDs. Video compression refers to reducing the quantity of Data used to represent video images and is a straightforward combination of Image compression and Motion Although digital technique allows for a wide variety of edit effects, most common is the hard cut and an editable video format like DV-video allows repeated cutting without loss of quality, because any compression across frames is lossless. While DV video is not compressed beyond its own codec while editing, the file sizes that result are not practical for delivery onto optical discs or over the internet, with codecs such as the Windows Media format, MPEG2, MPEG4, Real Media, the more recent H. 264, and the Sorenson media codec. Probably the most widely used formats for delivering video over the internet are MPEG4 and Windows Media, while MPEG2 is used almost exclusively for DVDs, providing an exceptional image in minimal size but resulting in a high level of CPU consumption to decompress.

While still images can have any number of pixels the video community defines one standard for resolution after the other and notwithstanding the devices use incompatible resolutions and insist on their resolution and rescale a video several times from the sensor to the LCD. Anamorph still images are the result of technical limitations while anamorph videos can be result of standardization aberrations. As of 2007, the highest resolution demonstrated for digital video generation is 33 megapixels (7680 x 4320) at 60 frames per second ("UHDV"), though this has only been demonstrated in special laboratory settings. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. In Digital imaging, a pixel ( pict ure el ement is the smallest piece of information in an image The highest speed is attained in industrial and scientific high speed cameras that are capable of filming 1024x1024 video at up to 1 million frames per second for brief periods of recording. A high speed camera is a device used for recording slow-motion playback films or used for scientific study of transient phenomena

Interfaces and cables

Many interfaces have been designed specifically to handle the requirements of uncompressed digital video (at roughly 400 Mbit/s):

• Serial Digital Interface
• FireWire
• High-Definition Multimedia Interface
• Digital Visual Interface
• Unified Display Interface
• DisplayPort
• USB

The following interface has been designed for carrying MPEG-Transport compressed video:

• DVB-ASI

Compressed video is also carried using UDP-IP over Ethernet. Serial digital interface (SDI refers to a family of Video interfaces standardized by SMPTE. The IEEE 1394 interface is a serial bus Interface standard for high-speed communications and Isochronous real-time data transfer frequently The High-Definition Multimedia Interface ( HDMI) is a compact audio/video connector interface for transmitting uncompressed digital streams The Digital Visual Interface ( DVI) is a Video interface standard designed to maximize the visual quality of digital Display devices such as Flat panel Unified Display Interface (UDI is a digital video interface specification based on Digital Visual Interface. DisplayPort is a digital display interface standard (approved May 2006 current version 1 The Moving Picture Experts Group, commonly referred to as simply MPEG, is a Working group of ISO / IEC charged with the development of video and For the chemical compound see Divinylbenzene. Digital Video Broadcasting ( DVB) is a suite of internationally accepted Asynchronous serial communication describes an asynchronous, serial transmission protocol in which a start signal is sent prior to each byte character or code word User Datagram Protocol ( UDP) is one of the core protocols of the Internet Protocol Suite. The Internet Protocol ( IP) is a protocol used for communicating data across a Packet-switched Internetwork using the Internet Protocol Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs Two approaches exist for this:

• Using RTP as a wrapper for video packets
• 1-7 MPEG Transport Packets are placed directly in the UDP packet

Storage formats

Encoding

All current formats, which are listed below, are PCM based. The Real-time Transport Protocol (or RTP) defines a standardized packet format for delivering audio and video over the Internet Transport stream ( TS, TP, MPEG-TS, or M2T) is a Communications protocol for audio, video, and data User Datagram Protocol ( UDP) is one of the core protocols of the Internet Protocol Suite.

• CCIR 601 used for broadcast stations
• MPEG-4 good for online distribution of large videos and video recorded to flash memory
• MPEG-2 used for DVDs and Super-VCDs
• MPEG-1 used for video CDs
• H.261
• H.263
• H.264 also known as MPEG-4 Part 10, or as AVC
• Theora standardized but still in development. ITU-R Recommendation BT601, more commonly know by the abbreviations Rec MPEG-4 is a collection of methods defining compression of audio and visual (AV digital data Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed MPEG-2 is a standard for "the generic coding of moving pictures and associated audio information" MPEG-1 was an early Standard for Lossy compression of Video and audio. H261 is a 1990 ITU-T video coding standard originally designed for transmission over ISDN lines on which data rates are multiples of 64 kbit/s H263 is a Video codec standard originally designed as a low-bitrate compressed format for Videoconferencing. H264 is a standard for Video compression. It is also known as MPEG-4 Part 10, or MPEG-4 AVC (for Advanced Video Coding) Theora is an open and royalty-free Lossy Video compression technology being developed by the Xiph used for video over the internet.

Tapes

• Betacam, BetacamSP, Betacam SX, Betacam IMX, Digital Betacam, or DigiBeta — Commercial video systems by Sony, based on original Betamax technology
• HDCAM was introduced by Sony as a high-definition alternative to DigiBeta. Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards Betacam is a family of half-inch professional Videotape products developed by Sony from 1982 onwards is a multinational conglomerate corporation headquartered in Minato Tokyo, Japan, and one of the world's largest Media conglomerates with ---- Betamax is a home Videocassette tape recording format developed by Sony, and released on May 10, 1975. HDCAM, introduced in 1997, is an HD version of Digital Betacam, using an 8-bit DCT compressed 311 recording in 1080i -compatible
• D1, D2, D3, D5, D9 (also known as Digital-S) — various SMPTE commercial digital video standards
• DV, MiniDV — used in most of today's videotape-based consumer camcorders; designed for high quality and easy editing; can also record high-definition data (HDV) in MPEG-2 format
• DVCAM, DVCPRO — used in professional broadcast operations; similar to DV but generally considered more robust; though DV-compatible, these formats have better audio handling. D-9 or Digital S as it was originally known is a professional digital videotape format created by JVC in 1995 Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor HDV is a High-definition_video format that uses MPEG2 compression to record HD content onto tapes originally designed for standard definition DV recording Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor
• DVCPRO50, DVCPROHD support higher bandwidths as compared to Panasonic's DVCPRO. Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor Digital Video (DV is a Digital video format created by Sony JVC Panasonic and other video camera procuers and launched in 1995 and in its smaller tape Form factor
• Digital8 — DV-format data recorded on Hi8-compatible cassettes; largely a consumer format
• MicroMV — MPEG-2-format data recorded on a very small, matchbook-sized cassette; obsolete
• D-VHS — MPEG-2 format data recorded on a tape similar to S-VHS

Discs

• Video CD (VCD)
• DVD
• HD DVD
• Blu-ray Disc
• Sony ProDATA

See also

External links

• The DV, DVCAM, & DVCPRO Formats -- tech details, FAQ, and links

Digital8 (or D8) is a consumer digital videotape format developed by Sony, and introduced in 1999 The 8 mm video format refers informally to three related Videocassette formats for the NTSC and PAL / SECAM television systems MicroMV was a videotape format introduced in 2001 by Sony. This cassette is physically smaller than a Digital8 or DV cassette D-VHS is a Digital video format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. Introduced in Japan in 1987, S-VHS ( Super VHS) is an improved version of the VHS standard for consumer Video cassette recorders DVD (also known as " Digital Versatile Disc " or " Digital Video Disc " - see Etymology)is not insert the publicly disclosed HD DVD key into this article for the time being Digital audio uses Digital signals for Sound reproduction. This includes analog-to-digital conversion, digital-to-analog conversion, storage Digital cinematography is the process of capturing Motion pictures as Digital images rather than on film. The Digital Visual Interface ( DVI) is a Video interface standard designed to maximize the visual quality of digital Display devices such as Flat panel DVD (also known as " Digital Versatile Disc " or " Digital Video Disc " - see Etymology)is HDV is a High-definition_video format that uses MPEG2 compression to record HD content onto tapes originally designed for standard definition DV recording HDVSL stands for High Definition Video over Subscriber Line. HDVSL is an Indian standard which has been specifically developed to address the need for a terminal free computing State of the Industry The US consumer appetite for high-definition television (HDTV programming is undeniable AVCHD ( Advanced Video Codec High Definition) is a high-definition and Standard-definition recording format for use in digital Tapeless camcorders High-definition (HD video generally refers to any video system of higher resolution than standard-definition (SD video most commonly at display resolutions of 1280×720 A camcorder is a portable Consumer electronics device for recording Video and audio using a built-in recorder unit A tapeless camcorder is a Camcorder that does not use Videotape to store its data The following is a list of Video -related topics Numbers 3D 43 601 169 A file hosting service, online file storage service, or online media center is an Internet hosting service specifically designed to host static content Television ( TV) is a widely used Telecommunication medium for sending ( Broadcasting) and receiving moving Images, either monochromatic Video is the technology of electronically capturing, Recording, processing storing transmitting and reconstructing a sequence of Still images Video coding is the field in electrical engineering and computer science that deals with representation of video data for storage and/or transmission for both analog and Digital Video editing software is Application software which handles the editing of video sequences on a computer A video sharing service allows individuals to Upload Video clips to an Internet website Video quality is a characteristic of a Video passed through a video transmission/processing system a formal or informal measure of perceived video degradation (typically compared Webcams ( web cameras) are small cameras (usually though not always Video cameras, whose images can be accessed using the World Wide Web, instant

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