What is HD?

June 13, 2013 / Posted by David Brooks on Related Technology

High-definition video or HD video refers to any video system of higher resolution than standard-definition (SD) video, and most commonly involves display resolutions of 1280×720 pixels (720p) or 1920×1080 pixels (1080i/1080p). This article will discusse the general concepts of high-definition video, as opposed to its specific applications in television broadcast (HDTV), video recording formats (HDCAM, HDCAM-SR, DVCPRO HD, D5 HD, XDCAM HD, HDV and AVCHD), the optical disc delivery system Blu-ray Disc and the video tape format D-VHS.

HD Video Content:

High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable, high definition disc (BD), internet downloads and the latest generation of video game consoles. Most computers are capable of HD or higher resolutions over VGA, DVI, and/or HDMI.

The optical disc standard Blu-ray Disc can provide enough digital storage to store hours of HD video content. DVDs look best on screens that are smaller than 36 inches (91 cm), so they are not always up to the challenge of today’s high-definition (HD) sets. Storing and playing HD movies requires a disc that holds more information, like a Blu-ray Disc.

HD Video on the Web:

A number of online video streaming/on demand and digital download services offer HD video, like YouTube, Vimeo, Hulu, Amazon Video On Demand, Netflix Watch Instantly, and others. Due to heavy compression, the image detail produced by these formats are far below that of broadcast HD, and often even inferior to DVD-Video (3-9 Mbit/s MP2) upscaled to the same image size.

HD in video surveillance:

An increasing number of manufacturers of security cameras now offer HD cameras. The need for high resolution, color fidelity, and frame rate is acute for surveillance purposes to ensure that the quality of the video output is of an acceptable standard that can be used both for preventative surveillance as well as for evidence purposes. These needs, however, must be balanced against the additional storage capacity required by HD video.

HD Video in Gaming:

The PlayStation 3 game console and Xbox 360 can output native 1080p through HDMI or component cables. Both systems have few games which appear in 1080p. Most games only run natively at 720p or less, but can be upscaled to 1080p. The Wii can output up to 480p (enhanced-definition) over component, which while not technically HD, is very useful for HDTVs as it avoids de-interlacing artifacts. The Wii can also output 576i in PAL regions.

Native 1080p produces a sharper and clearer picture compared to upscaled 1080p. Besides increasing the visual quality of games, users can also download or stream HD movies and video clips from the PlayStation Network or Xbox Video services to their respective consoles. The PlayStation 3 can also play Blu-ray Discs which hold HD data.

Though only a handful of games available have the native resolution of 1080p, all games on the Xbox 360 and PlayStation 3 can be upscaled up to this resolution. Xbox 360 and PlayStation 3 games are labeled with the output resolution on the back of their packaging, although on Xbox 360 this indicates the resolution it will upscale to, not the native resolution of the game.

An increasing number of PC games can be rendered in 1,920×1,080 or higher. Nintendo’s new console, the Wii U, supports HD.

Standard High-Definition video modes: 720p (1280 x 720), 1080i (1920 x 1080Interlaced), and 1080p (1920 x 1080)

Extra High-Definition video modes: 2000p (2048×1536), 2160p (3840×2160), 4000p (4096×3072), 2540p (4520×2540), and 4320p (7680×4320)

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