D9 This is assigned to Digital-S.

D10 This refers to Sony’s MPEG IMX VTRs that record I-frame only 4:2:2-sampled MPEG-2 SD video at 50 Mb/s onto half-inch tape. In bit rate, this sits IMX between Betacam SX and Digital Betacam. There is a Gigabit Ethernet card available which has caused some to dub it the eVTR as it can be considered more as a ‘storage medium’ for digital operations.

D11

The HDCAM VTR format has been assigned D11. D12

This is assigned to DVCPRO HD. D-20

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

A film-style digital camera from Arri that is highly modular and uses a single Super35mm-sized image CMOS sensor with a Bayer filter and producing the same field of view and depth of field as that of traditional 35mm film motion picture cameras. Like real film cameras it uses a detachable optical viewfinder – that is widely preferred to electronic versions on other cameras. It is capable of 1-60Hz frame rates, produces 1080-line images in 4:2:2 or 4:4:4. Website: www.arri.com

DAS

Direct Attached Storage, typically on hard disks, is available only to a single user as opposed to NAS that can be available to everyone on the network. Typically this uses SCSI, SAS or Fibre Channel protocol and provides add-on storage for servers that maintains high data rate and fast access.

Data carousel

This is a file system that rotates and delivers its content into a network at a defined point in a cycle – for example, teletext pages. It is a method to make a large amount of information or data files available within a reasonably short time after a request. The data is inserted into the digital broadcast transport stream. See also: IP over DVB

Data scanner

Sometimes used as a generic term for film scanner. Data recorders

Machines designed to record and replay data. They usually include a high degree of error correction to ensure that the output data is absolutely correct and, due to their recording format, the data is not easily editable. These compare with digital video recorders which will conceal missing or incorrect data by repeating adjacent areas of picture and which are designed to allow direct access to every frame for editing. Where data recorders are used for recording video there has to be an attendant ‘workstation’ to produce signals for video and audio monitoring, whereas VTRs produce the signals directly. Although many data recorders are based on VTRs’ original designs, and vice versa, VTRs are more efficient for pictures and sound while data recorders are most appropriate for data. They are useful for archiving and, as they are format-independent, can be used in multi-format environments. See also: DTF, LTO

Datacasting Broadcasting data. See: IP over DVB

dB See Decibel

DC28 SMPTE Task Force On Digital Cinema – intended to aid digital cinema development by determining standards for picture formats, audio standards and compression, etc.

DCI

Digital Cinema Initiatives, LLC was formed in 2002 with members including Disney, Fox, MGM, Paramount, Sony Pictures Entertainment, Universal and Warner Bros. Studios. Its purpose was to establish and document specifications for an open architecture for Digital Cinema components that ensures a uniform and high level of technical performance, reliability and quality control. It published the Digital Cinema System Specification in July 2005 (freely available at their website) establishing a set of technical specifications that have allowed the industry to move forward and start a large-scale roll-out of Digital Cinema. DCI describes a workflow from the output of the feature post production or DI, termed the Digital Source Master (DSM), to the screen. The Digital Cinema Distribution Master (DCDM) is derived from the DSM by a digital cinema post production process, and played directly into a digital cinema projector and audio system for evaluation and approval. The approved DCDM is then compressed, encrypted and packaged for distribution as the Digital Cinema Package (DCP). At the theater, it is unpackaged, decrypted and decompressed to create a DCDM* with images visually indistinguishable from those of the original DCDM. Website: www. dcimovies.com

DCDM See DCI

DCP

See DCI DC-SDI

An HD SDI dual link arrangement that is configured to carry live uncompressed DCI-sized 2K footage. That is 2048x1080 pixel images at 24P, with 12-bit 4:4:4 sampling in X´Y´Z´ color space. This involves a constant data rate of at least 1913 Mb/s, too much for a single HD-SDI, designed for 1080/60I/30P 10-bit 4:2:2 bit rate of 1248 Mb/s and audio. Hence the use of a dual link. See also: Dual link

DCT (compression) Discrete Cosine Transform – as a basic operation of MPEG video compression it is widely used as the first stage of compression of digital video pictures. DCT operates on blocks (hence DCT blocks) of the picture (usually 8 x 8 pixels) resolving them into frequencies and amplitudes. In itself DCT may not reduce the amount of data but it prepares it for following processes that will. Besides MPEG, JPEG, VC9, WM9 and DV compression depend on DCT. The use of blocks can lead to blocks being visible on screen where data rates that are too low are used. See also: DV, ETSI, JPEG, MPEG-2, MPEG-4, Wavelet

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GLOSSARY OF TERMS