HD DVD

Designed as the successor to the standard DVD format HD DVD can store about three times as much data as its predecessor – 15 GB single layer, 30 GB dual layer. It is often called 3x DVD as it has three times the bandwidth and storage of regular DVDs. The future for HD DVD is unclear as Blu-ray seems to have won the format war. See also: DVD, Optical disks Website: www.dvdforum.org

HDMI

The High-Definition Multimedia Interface is a digital audio and video interface able to transmit uncompressed streams. It is rapidly being adopted by both consumer and professional devices – from television sets, to set-top boxes, camcorders, game consoles and HD DVD/ Blu-ray Disc players. It replaces a pile of analog connections such as SCART, composite video, as well as DVI, audio and more. The data carried on HDMI is encrypted using High-bandwidth Digital Content Protection (HDCP) digital rights management technology – meaning that the receiving end needs to be able to decrypt HDCP.

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HDR, HDRI

High Dynamic Range Imaging techniques allow a greater dynamic range of exposure than normally possible, with the intention of accurately representing the wide brightness range of real scenes ranging from direct sunlight to shadows. This is sometimes used with computer-generated images or photography (by taking several pictures of a scene over a range of exposure settings) and it can provide a large amount of headroom for the adjustment of images in post production.

HD ready

This describes a television that can display the recognized 720 and 1080- line formats but does not include the tuner or decoder needed to receive the signals.

HD RGB This refers to HDTV signals in RGB form rather than Y,Cr,Cb form. The difference is that HD RGB is a 4:4:4 signal that can carry the full bandwidth of each of the R, G and B channels, whereas HD (TV) is normally considered to be in 4:2:2 form where the color difference signals have a more restricted bandwidth. Generally, the 4:2:2 form of HD is sufficient for many television applications and can be carried in its uncompressed form by a single HD- SDI connection. HD RGB is often used for critical keying shots for television, and for digital cinematography. The availability of a suitable VTR (HDCAM SR) makes working with the format generally more affordable.

HD-SDI See SDI

HDTV

High definition television. A television format with higher definition than SDTV. While DTV at 625 or 525 lines is usually superior to PAL and NTSC, it is generally accepted that 720-line and upward is HD. This also has a picture aspect ratio of 16:9. While there are many picture HDTV formats there is a consensus that 1080 x 1920 is a practical standard for global exchange of television material – a common image format. Many productions are made in this format. See also: 24P, ATSC, Common Image Format, DVB, Table 3 H HDV High definition DV is a tape format that stores long GOP MPEG-2 encoded HD video onto DV or MiniDV

tape cassettes. At its introduction in 2004, HDV represented a huge drop in price for HD camcorders. However the quality is ‘prosumer’ but it has opened up a new layer of operations for HD. Also the SD down converted output is better than the usual SD DV results. The use of long GOP coding impedes frame-accurate editing. See also: AVC-Intra

HE-AAC

See AAC, MPEG-4 Hexadecimal

A numbering system ,often referred to as ‘Hex’, that works to base 16 and is particularly useful as a shorthand method for describing binary numbers. Decimal 0-9 are the same as Hex, then 10 is A, 11 is B, up to 15 which is F. See also: Binary H HIPPI High performance parallel interface (ANSI X3.283-1996). Capable of transfers up to 200 MB/s (800 with the 6400 Mb/s HIPPI, a.k.a. GSN) it is targeted at high performance computing and optimized for applications involving streaming large volumes of data rather than bursty network activity. The parallel connection is limited to short distance and so Serial HIPPI is now available (a.k.a. GSN). See also: GSN Website: www.hnf.org

Holographic recording

A number of holographic recording systems are emerging as new ways of storing even more data onto 12 cm optical disks. ‘Holographic’ implies using optical techniques to record into the depth of the media, similar to modern high capacity hard (magnetic) disk drives that record successive tracks under one another below the disk’s surface. See also: HVD Website: www.inphase-technologies.com

HSDL

The High Speed Data Link is typically used to move uncompressed 2K, 10- bit RGB images (as used for digital film) within a facility. The data volumes involved are very large; each image is 12 MB, and at 24 fps this data amounts to 288 MB/s. HSDL provides an efficient transport mechanism for moving and sharing data between applications. It uses two SMPTE 292M 1.485 Gb/s serial links (HD-SDI) to provide nearly 3 Gb/s bandwidth and can result in close to realtime transfers at up to 15-20 f/s for 2K. Use of the SMPTE 292M data structure means the signal can be carried by the HD-SDI infrastructure – cabling, patch panels and routers that may already be in place for HD video. Images carried on HSDL can be imported as data to a workstation fitted with dual HD-SDI making them available for film restoration, compositing, editing, and film recorders. Archiving and transporting HSDL material can be done with data tape such as DTF-2 or LTO. See also: 2K, DTF, HD-SDI, LTO

HSM

Hierarchical Storage Management is a scheme responsible for the movement of files between archive and the other storage systems that make up hierarchical storage architecture. Typically there may be three layers of storage – online, near-line and offline – that make up the hierarchy that HSM manages. Managing these layers helps to run the archive and have the required speed of access to all stored material.

Hub (network)

Connects many network lines together as if to make them all part of the same wire. This allows many users to communicate but, unlike a switch, only one transaction can occur at once over the whole network. See also: CSMA/CD, Switch

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GLOSSARY OF TERMS