OFDM Orthogonal Frequency Division Multiplexing is a broadband multicarrier modulation method that offers superior performance and benefits over older, more traditional single-carrier modulation methods because it is a better fit with today's high-speed data requirements and operation in the UHF and microwave spectrum. The primary advantage of OFDM over single-carrier schemes is its ability to cope with severe channel conditions
OFDMA A multi-user version of the OFDM digital modulation method. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users. This allows simultaneous low data rate transmission from several users. Website: www.runcom.com
Offline (editing) A decision-making process using low-cost equipment to produce an EDL or a rough cut which can then be conformed or referred to in a high quality online suite - so reducing decision-making time in the more expensive online environment. Most offline suites enable shot selection and the defining of basic transitions such as cuts and dissolves which are carried by EDLs. It is only with the arrival of AAF that there has been an open standard for transporting a much wider range of decisions, including DVE, color corrections, as well as other metadata, between systems from different manufacturers. See also: AAF
OMFI Open Media Framework Interchange is an open standard developed by Avid, for post production interchange of digital media among applications and across platforms. Website: www.avid.com
One light (pass) A one-light pass refers to a film-processing lab giving the same exposure to a defined length of film, during printing. This is the simplest, quickest and cheapest way to print all the film and the results are typically used for making rushes, dailies, etc. These are often subsequently telecined and recorded to videotape as a reference for the offline decision-making process. See also: Best light
Online (editing) Production of the complete, final edit performed at full program quality. Being higher quality than offline editing, time costs more but the difference has narrowed as the cost of equipment has come down. Preparation in an offline suite will help save time and money in the online. To produce the finished edit, online has to include a wide range of tools, offer flexibility to try ideas and accommodate late changes, and to work fast to maintain the creative flow and to handle pressured situations.
Open Systems Interconnect (OSI) The OSI Basic Reference Model describes a general structure for communications, defined by the ISO, which comprises seven layers and forms a framework for the coordination of current and future standards - but not defining the standards themselves. Website: www.iso.ch
OpenEXR OpenEXR is a file format developed by Industrial Light & Magic for high dynamic range (HDR) images that are used in computer imaging applications. It is used by ILM on motion pictures, has become ILM's main image file format, and is released as free software. See also: Color Transform Language
Operating system (OS) The base program that manages a computer and gives control of the functions designed for general purpose usage - not for specific applications. Common examples are MS-DOS, Windows and Linux for PCs, OSX for Apple Macintosh and UNIX. For actual use, for example as a word processor, specific applications software packages are run on top of the operating system.
Optical disks Disks that use optical techniques for recording and replay of material without the read/ write heads touching the disk. These offer large storage capacities on 5.25-inch (12 cm) with technologies including CD, DVD, HD DVD, Blu-ray Disc and HVD, offering capacities of 700 MB, 4.7, 15, 25 and 200 GB, with all but CDs offering dual-layer capability or further generations to double the capacity. Single rate data transfer speeds are 1.23, 10, 36/72, 36/72 and 160 Mb/s - even with multiples of speed, data rates are generally still less than for hard drives. They are all available in ROM and read/write forms. Being removable and robust they provide excellent storage for data and digital media. See also: Blu-ray Disc, DVD, HD DVD, HVD, Professional Disc, XDCAM
Original Camera Negative (OCN) This is the exposed and developed negative film from the camera. Initially it is the only visual record of a shoot and so is highly valuable. Before digits got involved with film the OCN had to withstand being cut, edited and copied to a make a few master interpositives. Now it can be run just once through a film scanner and then put on the shelf. This reduces the risk of damage and makes a digital copy, that itself can easily be copied for further security.
Orthostereoscopic (Stereoscopic) A one-to-one condition where what is being displayed is the same as the 'real world'. For example IMAX 3D is often shot with parallel cameras spaced at the average human adult interpupillary distance (approx 63.5 mm) and with wide angle lenses that closely match an audience member's view of the screen.
Over sampling Sampling information at a higher resolution than is required for the output format. For example, an HD picture can be regarded as an over sampled version of SD. SD pictures created from down res'd HD are generally clearer, cleaner (lower noise) and sharper than those made directly in SD. An increasing amount of SD material is originated this way. Similarly, 35 mm film provides an over sampled source for SD and HD.