Binary

Mathematical representation of numbers to base 2, i.e. with only two states, 1 and 0; on and off; or high and low. This is the basis of the mathematics used in digital systems and computing. Binary representation requires a greater number of digits than the base 10, or decimal, system most of us commonly use everyday. For example, the base 10 number 254 is 11111110 in binary. There are important characteristics which determine good digital video equipment design. For example, the result of a binary multiplication contains the sum of digits of the original numbers. For example: 10101111 x 11010100 = 1001000011101100 (in decimal 175 x 212 = 37,100) Each digit is known as a bit. This example multiplies two 8-bit numbers and the result is always a 16-bit number. So, for full accuracy, all the resulting bits should be taken into account. Multiplication is a very common process in digital television equipment (e.g. keying, mixes and dissolves). See also: Bit, Byte, Digital mixing, Dynamic Rounding

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Bit (b) Binary digIT = bit. One mathematical bit can define two levels or states, on or off, black or white, 0 or 1 etc.; two bits can define four levels, three bits eight, and so on: generally 2n, where n = the number of bits. In image terms 10 bits can be used to define 1024 levels of brightness from black to white (with ITU-R BT.601 and 709, 64 = black and 940 = white). See also: Byte

Bit rate reduction (BRR) See Compression

BITC Burnt-in Timecode. Timecode that is displayed on the video to which it refers. This is often recorded to provide precise frame references for those viewing on equipment not supplied with timecode readers – originally domestic VCRs and these days, QuickTime viewers.

Blocks and Blocking See MPEG-2

Bluetooth Short-range, up to 100m, wireless data connection in a Personal Area Network. Bluetooth is used in products such as phones, printers, modems and headsets and is acceptable where two or more devices are in proximity to each other and not needing high bandwidth (2 Mb/s max.). It is easy to set up without configuration as Bluetooth devices advertise all services they provide making using the service easily accessible, without network addresses, permissions and all the other considerations that go with typical networks. Website: www.bluetooth.com

Blu-ray Disc (BD) This optical disk can hold 25 GB on a single-layer CD-sized (12cm) disk using 405 nanometer blue-violet lasers. Dual layer disks hold up to 50 GB. Players must be able to decode MPEG-2, H.264/AVC (MPEG-4 part 10) and SMPTE VC-1 coded material. MPEG-2 offers backward compatibility for DVDs while the other two more modern codecs are at least 50 percent more efficient, using less disk space or producing higher quality results. Audio codecs supported are Linear PCM, Dolby Digital, Dolby Digital Plus, Dolby TrueHD, DTS Digital Surround, DTS-HD. The baseline data rate is 36 Mb/s – giving over one-and-a-half hours recording of HD material

on a single layer, or about 13 hours of SD. For Blu-ray Disc movies (BD- ROM) the maximum transfer rate is 54 Mb/s for audio and video, with a maximum of 40 Mb/s for video. Random access allows easy video editing and simultaneous record and playback. The first BD disks were contained in a protective plastic caddy to avoid scratch damage. This made them somewhat bulky so now they are coated with a hard top layer to reduce the possibility of scratch damage and there is no caddy. See also: DVD, HD DVD, Optical disks, Professional Disc Website: www.blu-raydisc.com

Breaking the frame (Stereoscopic) Stereo objects in front of the screen plane (negative parallax) are problematic if they intersect the edge of frame, as contradictory depth cues are sent to the viewer. Essentially one cue is saying that the object is in front of the screen and another is saying that the object is behind it. This problem can be reduced in post production by a technique known as a ‘floating window’. This involves applying a partially transparent mask, reducing the strength of the cues on whichever side the object is breaking frame (and simultaneously if there are objects breaking frame both left and right). Another kind of issue is caused by objects moving backwards and forwards over the edge of frame. As an object moves off the edge of a screen one stereo camera signal is lost before the other. The result is that the stereo signal temporarily ‘switches off’. This can sometimes be solved by sizing up both images in post, causing the object to move off screen altogether.

Broadband General term referring to faster-than-telephone-modem connections, i.e. receiving (download) much faster than 56 kb/s and transmitting (upload) faster than 28 kb/s. Broadband connects subscribers to the internet via DSL or ADSL over the original copper telephone lines. Cable can offer higher data rates. The higher broadband speeds are capable of carrying live digital TV to homes. See also: ADSL

Browse

Method used with some stills stores, graphics systems and nonlinear editing systems to display a selection of reduced size or reduced resolution images to aid choice of stored clips or stills. For moving video, a timeline may be available so clips can be shuttled allowing the full sized images to be brought to use pre-cued. Browse/edit facilities are used in newsroom systems to provide video editing for journalists on their desktops. The material is stored on a browse server and distributed over a network to the many users. Details differ between models but some allow frame-accurate shot selections to be made with the resulting ‘cuts decision lists’ used to conform a broadcast quality version.

Bug

An error in a computer program that causes the system to behave erratically, incorrectly or to stop altogether. Term dates from the original computers with tubes and relays, where real live bugs were attracted by the heat and light and used to get between the relay contacts.

Bus

An internal pathway for sending digital signals from one part of a system to another.

BWF

Broadcast WAV file – an audio file format based on Microsoft’s WAV. It can carry PCM or MPEG encoded audio and adds the metadata, such as

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GLOSSARY OF TERMS