Broadcast and Media Technology Industry Glossary of Terms

compiled by Quantel

Abbreviations bit b

bits per second b/s byte B

bytes per second B/s frames per second f/s gigabits Gb

gigabits per second Gb/s gigabyte GB

gigabytes per second GB/s gigahertz GHz hertz Hz hours h kilobit kb

kilobits per second kb/s kilobyte kB kilohertz kHz megabit Mb megabyte MB megahertz MHz micro µ seconds s terabit Tb terabyte TB

TV standards descriptions TV standards are written in many different ways. The method used in this glossary is shown below and follows how they appear in ITU-R BT 709: i.e. Number of pixels per line x number of lines per frame/vertical refresh rate (in Hz) progressive or interlaced (P or I). For example: 1920 x 1080/50I

Notes: 1) The vertical refresh rate shown for interlaced scans is twice the whole frame rate (two interlaced fields make up one whole frame). This assumes that interlace is only ever 2:1 (theoretically it can be greater but never is for broadcast purposes). So 1920 x 1080 50I has 25 whole frames per second.

2) Digital standards are usually quoted for the active lines and pixels only – so no blanking space is included

Examples:

Digital SDTV in Europe 720 x 576/50I

(analog equivalent is 625/50I that includes 49 lines of blanking) An HD standard in USA 1920 x 1080/30P Brief format

Lines per frame/vertical refresh rate, progressive or interlaced e.g.: 1080/30P

A B C D E F G H I J

0:2:2

See: Dual Link 000/1001

The nominal 30 frames/60 fields per second of NTSC color television is usually multiplied by 1000/1001 (= 0.999) to produce slightly reduced rates of 29.97 and 59.94 Hz. This offset gives rise to niceties such as drop-frame timecode (dropping one frame per thousand – 33.3 seconds) and audio that also has to run at the right rate. Although having strictly analog origins from the very beginning of NTSC transmissions as a fix-it to avoid a clash of frequencies, it has also been extended into the digital and HD world where 24 Hz becomes 23.97 and 30 frames/60 fields per second are again changed to 29.97 and 59.94 Hz. Of course, as the frame/field frequency changes, so do the line and color subcarrier frequency as all are locked together. Note that this does not apply to PAL color systems as these always use the nominal values (25 Hz frame rate). See also: Drop-frame timecode, Embedded audio

10-bit lin

A type of digital sampling of analog images that creates 10-bit (210, 1024 possible levels) numbers to describe the post gamma corrected analog brightness levels of an image. Lin, short for ‘linear’ means the levels are assigned equally to the levels of the post gamma corrected analog signal they describe. So an LSB change describes the same change in level if it is in a bright area or a dark area of the picture. Most professional HD and some SD television is sampled this way according to ITU-R BT.601 and 709. 10-bit lin sampling allows good quality to be maintained through TV production and post production where the processes can make particular demands outside the range of normal viewing, and so produce good results for viewers. However if color grading is required then the useful wide dynamic range that can be described by 10-bit log would be preferable. See also: 10-bit log, gamma

10-bit log

This usually refers to a 10-bit sampling system that maps analog values logarithmically rather than linearly. It is widely used when scanning film

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GLOSSARY OF TERMS