Digital video
[1] The first practical semiconductor image sensor was the charge-coupled device (CCD), invented in 1969[2] by Willard S. Boyle, who won a Nobel Prize for his work in physics.
[11] Today, cameras from companies like Sony, Panasonic, JVC and Canon offer a variety of choices for shooting high-definition video.
[12] In the 1970s, pulse-code modulation (PCM) induced the birth of digital video coding, demanding high bit rates of 45-140 Mbit/s for standard-definition (SD) content.
[13] The first digital video coding standard was H.120, created by the (International Telegraph and Telephone Consultative Committee) or CCITT (now ITU-T) in 1984.
[14] H.120 was based on differential pulse-code modulation (DPCM), a compression algorithm that was inefficient for video coding.
During the late 1980s, a number of companies began experimenting with DCT, a much more efficient form of compression for video coding.
[19] Starting in the late 1970s to the early 1980s, video production equipment that was digital in its internal workings was introduced.
These included time base correctors (TBC)[b] and digital video effects (DVE) units.
Bosch's machine used a modified 1-inch type B videotape transport and recorded an early form of CCIR 601 digital video.
Due to this incompatibility the cost of the recorder, D1 was used primarily by large television networks and other component-video capable video studios.
[d] D1 & D2 would eventually be replaced by cheaper systems using video compression, most notably Sony's Digital Betacam, that were introduced into the network's television studios.
Other examples of digital video formats utilizing compression were Ampex's DCT (the first to employ such when introduced in 1992), the industry-standard DV and MiniDV and its professional variations, Sony's DVCAM and Panasonic's DVCPRO, and Betacam SX, a lower-cost variant of Digital Betacam using MPEG-2 compression.
[20] One of the first digital video products to run on personal computers was PACo: The PICS Animation Compiler from The Company of Science & Art in Providence, RI.
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 the introduction of the DV tape format allowing recordings in the format to be transferred directly to digital video files using a FireWire port on an editing computer.
This simplified the process, allowing non-linear editing systems (NLE) to be deployed cheaply and widely on desktop computers with no external playback or recording equipment needed.
The widespread adoption of digital video and accompanying compression formats has reduced the bandwidth needed for a high-definition video signal (with HDV and AVCHD, as well as several professional formats such as XDCAM, all using less bandwidth than a standard definition analog signal).
These savings have increased the number of channels available on cable television and direct broadcast satellite systems, created opportunities for spectrum reallocation of terrestrial television broadcast frequencies, and made tapeless camcorders based on flash memory possible, among other innovations and efficiencies.
[22] Digital video is increasingly common in schools, with students and teachers taking an interest in learning how to use it in relevant ways.
[23] Digital video also has healthcare applications, allowing doctors to track infant heart rates and oxygen levels.
[24] In addition, the switch from analog to digital video impacted media in various ways, such as in how businesses use cameras for surveillance.
[26] As compared to analog methods, DTV is faster and provides more capabilities and options for data to be transmitted and shared.
Since not all frames can be compressed at the same level, because quality is more severely impacted for scenes of high complexity, some algorithms try to constantly adjust the BPP.
Digital video cameras come in two different image capture formats: interlaced and progressive scan.
Progressive scan generally produces a slightly sharper image, however, motion may not be as smooth as interlaced video.
Digital video also allows footage to be viewed on location without the expensive and time-consuming chemical processing required by film.
Network transfer of digital video makes physical deliveries of tapes and film reels unnecessary.
Digital television (including higher quality HDTV) was introduced in most developed countries in early 2000s.
As of 2017[update], the highest image resolution demonstrated for digital video generation is 132.7 megapixels (15360 x 8640 pixels).
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.
