Huffman coding This compresses data by assigning short codes to frequently occurring long sequences and longer ones to those that are less frequent. Assignments are held in a Huffman Table. Huffman coding is lossless and is used in video compression systems where it can contribute up to a 2:1 reduction in data. See also: JPEG

HVD Holographic versatile disk – a ‘CD’ sized (120mm diameter) optical disc that will be capable of storing up to 1 TB. In 2007, the HVD Forum developed three HVD standards including those for a 200 GB recordable and 100 GB ROM. See also: Holographic recording Website: hvd-forum.org

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Hyperstereo (Stereoscopic) Using widely spaced cameras (e.g. beyond 70mm interocular) which record more stereo effect than the eyes can see. Such a large interocular distance can produce the effect of miniaturization. Also used in order to achieve the effect of more stereo depth and less scale in a scene. For stereo effects on very long shots (e.g. landscapes) interocular camera set ups of several meters have been used (hyperstereo). One extreme example of hyperstereo is from cameras on each side of the earth to record the sun in 3D. See also: Miniaturization, Interocular

Hypostereo (Stereoscopic) Using closely spaced cameras (e.g. less than 50 mm interocular) which record less stereo effect than the eyes can see. Such a small interocular distance can produce the effect of gigantism. If standard cameras are used, the minimum interocular distance is typically limited by the thickness of the cameras so a mirror or beam splitter system is often used, enabling interoculars down to millimeters. See also: Gigantism

IDTV Integrated Digital TV receiver. For viewers to receive DTV services they require a receiver either in the form of a new television set with the tuner and digital decoder built in (IDTV) or a set-top box. IDTVs typically include provision for all widely available terrestrial DTV services, so cable and satellite still require a set-top box. Note that although the set may be able to receive HD the screen may not be able to display the full sized 1080 x 1920 HD. In this case processing is included to re-size the pictures to fit the screen. See also: IRD, Table 3

IEEE 802.3 Standard that defines wired Ethernet. See: grouper.ieee.org/ groups/802/3/index.html

IEEE 1394 (a.k.a. FireWire, I-Link) A standard for a peer-to-peer serial digital interface which can operate at 100, 200, 400 or 800 Mb/s. IEEE 1394a specifies working up to 400 Mb/s, typically over copper cables up to 4.5 meters in length with six-pin connectors. Consumer devices use a four-pin connector. Extenders increase the maximum distance from 4.5 meters on copper cables up to about 100 meters on glass optical fiber. IEEE 1394b extends both data rate and distance: up to 1.6Gb/s on shielded twisted pair cable up to 4.5m, and has architecture to support 3.2Gb/s over 100m on optical fiber. See also: Asynchronous, Isochronous Website: www.1394ta.org

I-frame only (a.k.a. I-only) A video compression scheme in which every frame is intra-frame (I-frames) compressed, i.e. individually defined and does not depend on any other frames for decoding. There are no P (predictive) or B (bi-directional) frames in such compression schemes. This is considered preferable for studio use as edits can be made on any frame boundaries without necessarily involving processing. All DV compression is I-frame only. MPEG-2 and MPEG-4 with a GOP of 1 is I-frame only. For example these are used in Sony’s IMX VTRs and HDCAM SR respectively. JPEG 2000 is I-frame only. See also: Cut (edit), D11, GOP, Intra-frame (compression), JPEG 2000, MPEG-2, MPEG-4

I-Link See IEEE 1394

Illegal colors Colors that lie outside the limits, or gamut, of a particular color space. These can be generated when moving images from one color space to another, as they all have different boundaries, or as the result of color processing. For example, removing the luminance from a high intensity blue or adding luminance to a strong yellow in a paint system may well send a subsequent PAL or NTSC coded signal too high or low – producing at least inferior results and maybe causing technical problems. Out-of-gamut detectors can be used to warn of possible problems and correction is also available. Some broadcasters reject material with illegal colors.

IMX

See D10 InfiniBand

InfiniBand defines an input/output architecture that can connect servers, communications infrastructure equipment, storage and embedded systems. It can achieve data transfers up to 120GB/s over copper and optical fiber connections, with the benefits of low latency and only requiring a low processing overhead. It is used in many data centers, high-performance computer clusters and embedded applications that scale from two nodes up to a single cluster that interconnect thousands of nodes.

ING IT-News Gathering – coined by Panasonic to highlight their use of Secure Data (SD) memory as the in-camera media store for their DVCPRO P2 (P2 Cam) news cameras. See also: DV, ENG

In-server editing Editing at a workstation which directly edits material stored in a server. For this the workstation does not need large-scale video and audio storage but depends totally on the server store. The arrangement allows background loading of new material, via several ports if required, and playout of finished results, while avoiding any need to duplicate storage or transfer material to/from the workstation and allowing any number of connected workstations to share work. The efficiency of in-server editing allows fast throughput and is specially attractive to news as well as to post production where jobs can be instantly available in rooms, or move between rooms. This depends on using a server that can act as an edit store and perform reliable video replay and record. It also requires a powerful interface to the edit workstation. See also: Delta editing

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GLOSSARY OF TERMS