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Glossary of Terms

Glossary of Terms

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A/D
Analog to digital conversion.

Addressable Resolution
The inherent resolution of a display device (plasma screen, television, projector or monitor) which enables pixels to be individually addressed. The device, however, may not be capable of displaying this resolution.

Aliasing
An artifact produced by distorting or not using the high frequency components of an image, signal, data stream, etc. due to some limitation such as undersampling or inadequate detection bandwidth. The result is unwanted appearance of low frequency components (aliases) which must be filtered out and replaced with the missing high frequency components. The process of removal/replacement of frequencies is called "anti-aliasing".

Analog
A form of data transmission using a continuously variable signal, in contrast to digital transmission, which uses discrete numerical steps.

Analog TV
"Standard" television broadcasts analog TV. Analog signals vary continuously, representing fluctuations in color and brightness. NTSC is an analog system.

Anamorphic
A process of storing images with different horizontal and vertical magnifications for later display through a reversed procedure. Generally, the image is squeezed inward from the sides in relation to the height. So, if the original picture is of a circle, then the anamorphic processing would produce a tall, thin oval. On receiving the signal, some device will readjust these different horizontal and vertical magnifications back to normal. The anamorphic process has the advantage of enabling wide aspect ratio pictures to be stored on a recording medium originally designed for the 4x3 aspect ratio. Specifically, an anamorphic DVD stores a high quality widescreen movie for viewing on widescreen TVs.

ANSI Lumens
A unit that indicates lumen brightness of projectors. ANSI (American National Standards Institute) has established the standard for measurement of lumen brightness. For example, if one projector uses Halogen lamps and another metal-halide, the halogen projector will seem noticeably dimmer even if the two units rate the same.

Anti-aliasing
In electronic communication, the term refers to the adding of additional images or parts of images so as to convince the eye that it sees something that cannot be represented digitally. The goal is usually to make curved or diagonal lines appear smooth, or to show straight horizontal or vertical lines in certain positions. Lines cannot be represented smoothly or in the proper position because the display device resolution is not sufficient to represent the image accurately. In practice, the eye is fooled into completing the edge between the background and foreground colors.

Artifacts
Unwanted visible effects in a picture created by disturbances in the transmission or image processing, for example "edge crawl" or "hanging dots" in analog pictures, or "pixelation" in digital images.

Aspect Ratio
The aspect ratio of a display screen is described by the width x height, for example 4x3 means 4 units wide by 3 units high. Current U.S. TV broadcasts use a 4:3(1.33:1) aspect ratio. Digital TV is broadcast with a 16:9 (1.78:1) ratio, and most feature films are shot in the ratio range of 1.85:1 up to 2.35:1.

ATSC
The Advanced Television Systems Committee Inc., is an international, non-profit organization developing voluntary standards for digital television. The ATSC member organizations represent the broadcast, broadcast equipment, motion picture, consumer electronics, computer, cable, satellite, and semiconductor industries. The most common formats are 480p (525 scan lines, 480 of them active, per frame progressive scan, each scan line divided into 640 or 704 parts or pixels, 720p which is 720 active scan lines each with 1280 pixels, and 1080i (1080 active scan lines as two 540 scan line interlaced fields, 1920 pixels on a line).

ATTC
The Advanced Television Technology Center is a private, non-profit corporation organized by members of the television broadcasting and consumer products industries to test and recommend solutions for delivery and reception of a new U.S. terrestrial transmission system for digital television (DTV) service, including high definition television (HDTV). The Technology Center operates a state-of-the-art laboratory facility that supports the needs of the U.S. television industry and private standards-setting bodies. Its primary activity is to facilitate implementation of digital television. Website: www.attc.org

Deinterlacing

Learn About Deinterlacing

Deinterlacing: the conversion of a video signal from interlaced to progressive

Why deinterlace?
Modern pixel-based displays (LCD, DLP, LCOS, plasma,…) are progressive scan and require progressively scanned video sources, whereas many older video devices use the older interlaced scan technology.

Interlaced Scan: a complete image frame is encoded in two fields - one containing all the odd lines, and the next containing all the even lines. When displayed, the image is drawn with all the odd lines being scanned from top to bottom, followed by all the even lines top to bottom. Sixty separate fields are shown every second.

Examples of interlaced signals:

Standard Definition (480i): DVD, SD broadcast / cable, VCR, laserdisc,…

High Definition (1080i): HD broadcast / cable, DVHS, game consoles,…

Progressive Scan: a complete image frame contains all the lines of the picture, in order, from top to bottom. When displayed, each image frame is drawn in a single scan from top to bottom. Sixty complete frames are shown per second.

Examples of progressive signals:

Standard Definition (480p): progressive scan DVD players, progressive output from set top boxes

High Definition (720p): HD broadcast / cable, game consoles VESA (XGA@60HZ): Home Theater PC (HTPC), Laptop

The problems of Deinterlacing

There are a number of challenges in converting an interlaced video source into progressive scan format. Here are two of the main issues that a video deinterlacer has to deal with:

Motion Adaptive - allow for the movement of objects in the time between the two interlaced fields of a frame. Edges should be smoothed, but without losing detail. Our eyes are very good at detecting the slightest jagged edge, or hesitation in movement.

Film Source - detect original film source material that has been adapted for dvd and reverse that process (apply inverse 3:2 pulldown). Works on film are generally adapted to TV format by repeating every 3rd or 5th frame in order to bring it up to the right number of frames per second. When deinterlacing, it is important to allow for the duplicate frames to keep movement and edges smooth.

Not all Deinterlacers are created equal

Displays may have their own built-in deinterlacers, but these tend to be of inferior quality. Artifacts resulting from the slight time difference between interlaced fields can cause strange effects, and flickering may be a problem.

DVDO's Precision Deinterlacing™ technology delivers the image quality demanded by today's large-screen, high-resolution displays. It eliminates many of the artifacts found in common deinterlacers to produce a smooth image, free of artifacts such as jagged edges and combing.

Precision Deinterlacing features five-field motion-adaptive deinterlacing and edge-adaptive processing for video sources, along with advanced cadence detection for film and animation sources. All processing is performed at full 10-bit resolution to preserve all the detail and subtle nuances in the video source. Edge-adaptive processing uses an adaptive, continuous-angle detection algorithm to accurately identify and smooth image edges.

Unique, "any-cadence" processing automatically locks to the wide variety of film and animation cadences found in current video sources, including non-standard cadences, and will track right through many types of "bad edits" and cadence changes. The Precision Deinterlacing Card also features operating modes for special video applications, such as low-latency processing for video games, where timing is essential.

Game Mode

Learn About Game Mode

Game Mode: faster reaction time

Anchor Bay's Precision Deinterlacing Card offers a Game Mode - What does that mean?

The complex algorithms involved in video processing take time to run. If you're watching a DVD, TV program or a movie, the slight delay between input and output is not apparent, and the quality of the displayed images is of prime importance. However, for gaming applications, the ability to minimize that processing delay is crucial. Many competitive video processors produce upwards of a 7 frame delay as they apply the algorithms. This can mean an unacceptable delay for serious gamers who want a real-time response to their commands in order to get peak performance from their applications.

  • Game Mode 1: slightly less than one frame delay, while still performing edge adaptive deinterlacing.

  • Game Mode 2: will reduce frame delay down to 2 frame delay with edge and motion adaptive processing

The Precision Deinterlacing Card is an optional extension module for the DVDO iScan VP30 or iScan VP20.

HDCP

Learn About HDCP

HDCP - What is it?

The latest iScan models offer HDCP compliance and scaling of HD sources over DVI. What does that mean?

High-Bandwidth Digital Content Protection (HDCP) is a standard, developed by Intel, designed to protect digital video and audio signals transmitted over DVI connections between two HDCP-enabled devices.

A digital signal still retains perfect clarity, even after being copied an unlimited number of times. So, in order to protect copyright holders (movie studios, etc.) from having their programs copied and shared, the HDCP standard provides for the secure, encrypted transmission of digital signals.

HDCP functions across DVI and HDMI connections between two HDCP capable devices. The source device (such as a DVD player or HDTV tuner) encrypts the digital signal using the HDCP standard, then sends that signal over the DVI or HDMI link to the receiving device (HDTV, etc.). The receiving device decodes the signal using HDCP and uses the signal as it is allowed.

If one of your devices is HDCP compliant, but the other is not, then you cannot connect them using DVI or HDMI - you will get an error. However, you can still use the analog signal from the source device (eg: component video signal, S-video signal). HDCP does not apply to analog signals.

The FCC approved HDCP as a "Digital Output Protection Technology" on August 4th, 2004. FCC regulations require digital output protection technologies on all digital outputs from HDTV signal demodulators as of July 1st, 2005.

DVI

Digital Visual Interface (DVI) is a type of cable and connection created by the Digital Display Working Group (DDWG), a cooperative of technology companies including Silicon Image, Intel, Compaq, Fujitsu, HP, IBM and NEC.

The DVI 1.0 standard was originally created to enable digital-to-digital, high bandwidth data transfer between a computer and a flat screen monitor. However, because of DVI's ability to process high-bandwidth HDTV video, its use was expanded into the consumer electronics industry.

DVI is the fastest way to transfer data or video. Using DVI with a digital display device, such as a projector or flat screen monitor, will create an entirely digital-to-digital connection, providing the best quality image.

The DVI 1.0 specification defines the following terms:

DVI-D Digital Only 
DVI-I Digital and Analog 
Dual Link Dual Link DVI supports 2x165 MHz (2048x1536 at 60 Hz, 1920x1080 at 85 Hz). A dual link implementation utilizes all 24 of the available pins.
Single Link Single Link DVI supports a maximum bandwidth of 165 MHz (1920x1080 at 60 Hz, 1280x1024 at 85Hz). A single link implementation utilizes 12 of the 24 available pins.

HDMI

High Definition Multimedia Interface (HDMI) is the first industry-supported, uncompressed, all-digital audio/video interface. Based on the earlier DVI (video only) standard, HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, and A/V receiver and an audio and/or video monitor, such as a digital television (DTV). HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable. It transmits all ATSC HDTV standards and supports 8-channel digital audio, with bandwidth to spare to accommodate future enhancements. HDMI does offer 'legacy' support of older DVI connections.