images which are themselves a logarithmic representation of the film’s exposure. This form of sampling is now available directly from some digital cinematography cameras. See also: 10-bit lin

13.5 MHz This is the sampling frequency of luminance in SD digital television. It is represented by the 4 in 4:2:2. The use of the number 4 is pure nostalgia as 13.5 MHz is in the region of 14.3 MHz, the sampling rate of 4 x NTSC color subcarrier (3.58 MHz), used at the very genesis of digital television equipment. See: 4:1:1, 4:2:0, 4:2:2, 4:4:4, 4fsc, Nyquist (frequency)

14:9

A picture aspect ratio that has been used as a preferred way to present 16:9 images on 4:3 screens. It avoids showing larger areas of black above and below letterboxed pictures but does include more of the 16:9 image than 4:3. It is commonly used for analog transmissions that are derived from 16:9 digital services.

16:9

A B C D E F G H I J

K L

M N O P Q R S T U V

W X Y Z

Picture aspect ratio used for HDTV and some SDTV (usually digital). See also: 14:9, 4:3, Widescreen

24P

Refers to 24 frames-per-second, progressive scan. 24 f/s has been the frame rate of motion picture film since talkies arrived. It is also one of the rates allowed for transmission in the DVB and ATSC digital television standards – so they can handle film without needing any frame-rate change (3:2 pull-down for 60 fields/s ‘NTSC’ systems or running film fast, at 25f/s, for 50 Hz ‘PAL’ systems). 24P is now accepted as a part of television production formats – usually associated with high definition 1080 lines to give a ‘filmic’ look on 60 Hz TV systems. See also: 24PsF, 25P, 3:2 Pull-down, ATSC, Common Image Format, DVB, Versioning

24PsF (segmented frame)

A system for recording 24P images in which each image is segmented – recorded as odd lines followed by even lines. Unlike normal television, the odd and even lines are from an image that represents the same snapshot in time. It is analogous to the scanning of film for television. This way the signal is more compatible (than normal progressive) for use with video systems, e.g. VTRs, SDTI or HD-SDI connections, mixers/switchers etc., which may also handle interlaced scans. Also it can easily be viewed without the need to process the pictures to reduce 24-frame flicker. See also: Interlace Factor, Progressive

25P

Refers to 25 f/s, progressive scan. Despite the international appeal of 24P, 25P is widely used for HD productions in Europe and other countries using 50 Hz TV systems. This is a direct follow-on from the practice of shooting film for television at 25 f/s. See also: 24P, 24PsF, Common Image Format, DVB

2K See Film formats 4:2:2

3:2 Pull-down (a.k.a. 2:3 Pull-down) A method used to map the 24 or 23.98 f/s of motion picture film onto 30 or 29.97 f/s (60 or 59/94 fields) television, so that one film frame

A ratio of sampling frequencies used to digitize the luminance and color difference components (Y, R-Y, B-Y) of an image signal. The term 4:2:2 denotes that for every four samples of the Y luminance, there are two

3Gig To meet the emerging demands of increased resolution for high-definition capture, transport, storage and production of video images, equipment is being offered with SMPTE 424M compliant physical layer connections supporting 2.97 Gb/s data rates, or 3Gig for short.

3G A marketing term derived from 3Gig but encompassing the 1080p standard

4:1:1

This is a set of sampling frequencies in the ratio 4:1:1, used to digitize the luminance and color difference components (Y, R-Y, B-Y) of a video signal. The 4 represents 13.5 MHz, (74.25 MHz at HD) the sampling frequency of Y, and the 1s each 3.75 MHz (18.5625) for R-Y and B-Y (i.e. R-Y and B-Y are each sampled once for every four samples of Y). With the color information sampled at half the rate of the 4:2:2 system, this is used as a more economic form of sampling where video data rates need to be reduce. 4:1:1 sampling is used in DVCPRO (625 and 525 formats), DVCAM (525/NTSC) and others. See also: 4:2:0, 4:2:2, DV (DVCAM and DVCPRO)

4:2:0

A sampling system used to digitize the luminance and color difference components (Y, R-Y, B-Y) of a video signal. The 4 represents the 13.5 MHz (74.25 MHz at HD) sampling frequency of Y while the R-Y and B-Y are sampled at 6.75 MHz (37.125 MHz) – effectively on every other line only (i.e. one line is sampled at 4:0:0, luminance only, and the next at 4:2:2). This is used in some 625-line systems where video data rate needs to be reduced. 4:2:0 is widely used in MPEG-2 coding meaning that the broadcast and DVD digital video seen at home is usually sampled this way. 625 DV and DVCAM coding also use 4:2:0. However the different H and V chroma bandwiths make it inappropriate for post applications. See also: 4:1:1, 4:2:2, DV (DVCAM), MPEG-2

occupies three TV fields, the next two, etc. It means the two fields of every other TV frame come from different film frames making operations such as rotoscoping impossible, and requiring care in editing.

3D (graphics)

Applied to graphics, this describes graphics objects that are created and shown as three-dimensional objects. As computer power has increased, so has the ability to cost-effectively produce more and more detailed 3D graphic results – as seen in feature length animations. For television presentation, live 3D computer graphics is now commonplace – even in HD. The considerable computational power needed for this is generally supplied by GPUs.

3D (stereo)

In television, film or cinema, 3D may refer to material that is shot using a set of ‘stereo’ cameras and shown on the screen as a pair of superimposed stereo images (usually ‘decoded’ by the viewer with polarized spectacles). Also known as stereo3D and stereoscopic 3D. See also: Stereoscope

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GLOSSARY OF TERMS