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Concept
Digital video
Résumé
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 a series of s displayed in rapid succession, usually at 24, 30, or 60 frames per second. Digital video has many advantages such as easy copying, multicasting, sharing and storage.
Digital video was first introduced commercially in 1986 with the Sony D1 format, which recorded an uncompressed standard-definition component video signal in digital form. In addition to uncompressed formats, popular compressed digital video formats today include H.264 and MPEG-4. Modern interconnect standards used for playback of digital video include HDMI, DisplayPort, Digital Visual Interface (DVI) and serial digital interface (SDI).
Digital video can be copied and reproduced with no degradation in quality. In contrast, when analog sources are copied, they experience generation loss. Digital video can be stored on digital media such as Blu-ray Disc, on computer data storage, or streamed over the Internet to end users who watch content on a desktop computer screen or a digital smart TV. Today, digital video content such as TV shows and movies also includes a digital audio soundtrack.
The basis for digital video cameras is metal–oxide–semiconductor (MOS) . The first practical semiconductor image sensor was the charge-coupled device (CCD), invented in 1969 by Willard S. Boyle, who won a Nobel Prize for his work in physics. Following the commercialization of CCD sensors during the late 1970s to early 1980s, the entertainment industry slowly began transitioning to digital imaging and digital video from analog video over the next two decades. The CCD was followed by the CMOS active-pixel sensor (CMOS sensor), developed in the 1990s. CMOS are beneficial because of their small size, high speed, and low power usage. CMOS are most commonly found today in the digital cameras in iPhones, used as the image censor for the device.
Source officielle
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