High-definition video
[citation needed] 480 scan lines is generally the minimum even though the majority of systems greatly exceed that.
Images of standard resolution captured at rates faster than normal (60 frames/second North America, 50 fps Europe), by a high-speed camera may be considered high-definition in some contexts.
Modern HD specifications date to the early 1980s, when Japanese engineers developed the HighVision 1,125-line interlaced TV standard (also called MUSE) that ran at 60 frames per second.
[1] Digital HDTV was enabled by the development of discrete cosine transform (DCT) video compression.
[2] The current high-definition video standards in North America were developed during the course of the advanced television process initiated by the Federal Communications Commission in 1987 at the request of American broadcasters.
In essence, the end of the 1980s was a death knell for most analog high definition technologies that had developed up to that time.
However, both Brazil and China have adopted alternative standards for high-definition video[citation needed] that preclude the interoperability that was hoped for after decades of largely non-interoperable analog TV broadcasting.
The aspect ratio of regular widescreen film shot today is typically 1.85:1 or 2.39:1 (sometimes traditionally quoted at 2.35:1).
HD DVD discs were primarily developed by Toshiba and NEC with some backing from Microsoft, Warner Bros., Hewlett Packard, and others.
On February 19, 2008, Toshiba announced it was abandoning the format and would discontinue development, marketing and manufacturing of HD DVD players and drives.
Depending upon available bandwidth and the amount of detail and movement in the image, the optimum format for video transfer is either 720p24 or 1080p24.
When shown on television in PAL system countries, film must be projected at the rate of 25 frames per second by accelerating it by 4.1 percent.
In addition some films have a wider dynamic range (ability to resolve extremes of dark and light areas in a scene) than even the best HD cameras.
Thus the most persuasive arguments for the use of HD are currently cost savings on film stock and the ease of transfer to editing systems for special effects.
Depending on the year and format in which a movie was filmed, the exposed image can vary greatly in size.
The four major film formats provide pixel resolutions (calculated from pixels per millimeter) roughly as follows: In the process of making prints for exhibition, this negative is copied onto other film (negative → interpositive → internegative → print) causing the resolution to be reduced with each emulsion copying step and when the image passes through a lens (for example, on a projector).
The ever-evolving image sensor technologies allowed manufacturers to develop cameras with 10-20 MP resolutions, which therefore have become efficient instruments to monitor larger areas.
Such high resolutions, however, requires special recording, storage and also video stream display technologies.
