HD?

HiDef comes in many shapes and sizes.

In theaters, the IMAX HD format, used at Disney’s California Adventure theme park, “Soarin’ Over California,” for example, has 7,000 lines of resolution (10,000×7,000), with filming and projection in 70 mm at 48 frames per-second, or twice the normal film frame rate of 24 fps.

For ordinary theaters, 35 mm film original camera negative can be as much as 6,000 lines of resolution, scanned for editing at anywhere from 2,000 – 8,000 (2k, 4k, or 8k), with theater projection at about 2,000 lines of resolution.

In digital video, Blu-ray Disc, D-VHS, and HDCAM SR can deliver as much 1080 lines of resolution (1920×1080) or 720 lines (1280×720). HDV resolves at 810 lines (1440×1080) or 720.

In the home, the format best capable of delivering full 1080p HiDef is Blu-ray Disc viewed on an LCD or plasma TV capable of displaying 1080p. Even then, quality levels can vary from disc to disc depending on bit rates (see definition below). Blu-ray bit rates can be as high as 48 megabits per second for video and audio, with uncompressed or lossless 5.1 channel audio.

Currently television mostly offers something less than that via broadcast, cable, and satellite, with the differences often varying greatly from one channel to another, and even from one program to another on the same network. Satellite services are just beginning to offer a few video-on-demand/PPV channels with 1080p but with more image compression and substantially lower bit rates (see below definition) than physical media like a Blu-ray disc.

A new Ultra HD technology is being developed for TV and Blu-ray that may be set at one of two levels of resolutions, 3840×2160 (4K) or 7680×4320 (8K).

The glossary below provides definitions to help you sort it all out.

High definition Glossary

16:9 — The screen proportions of HDTV. The width is 1.778 times the height, compared to conventional 4:3 television, 16:9 “widescreen” viewing is closer to the proportions of a movie screen.

7.1 Channel Surround Sound — Digital high-quality audio system delivered under names such as Dolby Digital Plus, Dolby TrueHD, and DTS-HD that offers 7 audio channels and one Low Frequency Effects (LFE; subwoofer) channel. The seven channels are configured to be delivered through three speakers each on the left and right sides of the room — front, center, back — and a front center channel.

720p — A term referring to the amount of resolution of a high-definition display/monitor — 720 lines of vertical display resolution in the “progressive scan” mode (lines scanned sequentially from top to bottom). Although a 720p display has significantly less picture resolution than a 1080p display, 720p has nearly the same amount of video information as a 1080i display (1080 lines of resolution in the “interlaced” mode) because it has twice as many video frames per second: 60 vs. 30.  The higher frame rate has no impact on film-based sources like motion picture content, which is typically shot at 24 frames per second. Many of the major broadcast and cable networks use 720p as the standard for HDTV programming.

1080i — A term referring to the amount of resolution of a high-definition display/monitor — 1080 lines of vertical resolution in the “interlaced” mode (odd numbered lines scanned first from top to bottom, followed by even numbered lines). A 1080i display has significantly higher picture resolution than a 720p display but fewer video frames per second than 720p

1080p — A term referring to the amount of resolution of a high-definition display/monitor — 080 lines of vertical display resolution in the progressive scan mode (lines scanned sequentially from top to bottom), which avoids the need to interlace two fields to make each frame. By eliminating interlacing, 1080p can reproduce images that are the closest possible to the original film presentation. 1080p has significantly higher picture resolution than the 720p HDTV standard of many major broadcast and cable networks.

Bitrate —  the amount of information (digital bits) stored and/or processed per unit of playback time after source coding (data compression). The more bits of information the higher quality the image, particularly in video with lots of movement and animation, where many elements of the image are changing rapidly. In the case of video in the home, the measure is in megabits-per-second.

Some examples:

* DVD = 5 Mbit/s

* HDTV = 8 to 15 Mbit/s

* Blu-ray = 48 Mbit/s

Blue Laser — A laser beam with a much shorter wavelength than the red laser used with DVD, allowing it to be focused to a much smaller sized spot on the data layer in the disc and thereby allowing the reading of much more densely packed information in the same amount of space.

Blu-ray Disc — The next-generation home video optical disc format that can reproduce full 1080p high-definition video resolution, five times the storage space of DVDs (up to 9 hours of high-definition video on a dual-layer 50 GB Blu-ray Disc), the best audio, backward compatibility, and enhanced interactivity; supported by nearly every studio, content provider, consumer electronics and computer manufacturer. The name refers to the blue laser used in the player that reads the data on the disc.

HDMI connector — Short for High-Definition Multimedia Interface. An all-digital audio/video interface (output connector) capable of transmitting uncompressed streams of high-definition video and multi-channel audio signals through a single cable to compatible components. In other words, a single cable that connects to your video display monitor and your Blu-ray player that transmits the highest quality signal. It’s a replacement for the analog audio/video, RF and S-Video inputs/outputs on your previous set-top players and video game systems.

HDTV — High-Definition Television. Generic term used for TV technology producing images in a much higher-quality picture than standard definition TVs. An HDTV set displays as high as 720 lines to 1,080 lines of vertical resolution. While most HDTV sets are digital, not all digital TVs are HDTVs.

High-definition — High-definition is a standard referring to digital video of a specific horizontal rectangular shape (16:9 aspect ratio, or 1.78 times wider than its height) and of a specific minimum resolution standard (720 lines to 1,080 lines). By comparison, standard-definition digital video and TV has a more square-ish shape with an aspect ratio of 4:3 (1.33 times wider than its height) and 480 vertical lines of resolution.

Interlaced Video/Interlaced Scanning — The way almost all TVs (CRT: cathode-ray tubes) for decades created a picture by rapidly scanning odd numbered lines on the screen from top to bottom, and then repeating the process for even numbered lines, which can cause a flicker in the image and other motion artifacts. Interlaced scanning is still used on standard TVs and even in the 1080i high-definition standard. Computer monitors and LCD and plasma displays are inherently progressive scan devices, which means they build a picture on the screen by scanning every line in order from top to bottom, even if they must convert them from interlaced signals.

Layer — An optical disc such as Blu-ray Disc can store data (such as video and audio) on a single 25 GB storage layer inside the disc or on two data layers on the same side of the disc. In a dual-layer disc (50 GB), the blue laser will first read from or record to one layer, and then re-focus through the top layer onto the second layer in a seamless transition.

LCD TV — Liquid Crystal Display. A thin, flat video display made up of pixels in front of a light source or reflector that became popular in the early 2000s as computer monitors and now compete with plasma flat panel TVs and rear-projection TVs in the large-screen HDTV market.

Plasma TV — Plasma Display Panels (PDP) are a type of thin flat panel display now commonly used for large screen TVs that generate bright images by putting many tiny cells between two panels of glass holding an inert mixture of neon and xenon gases that are electrically turned into a plasma which then excites phosphors to emit light.

Progressive Scan — Computer monitors, LCD and plasma displays use progressive scan, which builds a superior image by rapidly scanning every line on the screen sequentially from top to bottom. This is in contrast to interlaced scanning, the method used by all standard TVs (with cathode-ray tubes) and the 1080i high-definition standard, which builds a picture by first scanning odd numbered lines on the screen, and then repeating the process with even numbered lines, which can cause a flicker in the image and other distortions.

SDTV/Standard Definition TV — The picture quality level of traditional TVs 480 lines to 570 lines of vertical resolution based on the standards of NTSC (North America, Japan, South Korea, and others) or PAL (Europe and other territories).

Upconvert/Upscale (High-definition Upconverter/Upscaling) — Some newer DVD players “upconvert” or “upscale” standard definition video on DVDs to an HDTV-like picture that can be viewed on a high-definition display. The HD upconverting process enhances the lower resolution of the SDTV output of DVD discs in order to simulate HDTV quality video.  Although upconverted SDTV pictures can look better than standard DVD, true high definition video quality can only come from a true high def source such as a Blu-ray Disc player. Many Blu-ray players also do upconverting of DVDs during playback.