The Digital Fact Book - Quantel

BetacamAn analog component VTR system for PAL and NTSC television introduced in 1982, usinga half-inch tape cassette – very similar to the domestic Betamax. This was developed bySony and was marketed by them and several other manufacturers. Betacam records the Y,R-Y and B-Y component signals onto tape; many machines were operated with coded (PALor NTSC) video in and out. Initially developed for the industrial and professional marketsthe system was enhanced to offer models with full luminance bandwidth (Betacam SP 1986),PCM audio and SDI connections with a great appeal to the broadcast market.BDigital Betacam – Introduced in 1990 it was a development of the original analog BetacamVTR that records SD component video and audio digitally onto Betacam-style cassettes.It uses mild intra-field compression to reduce the ITU-R BT.601 sampled video data by about2:1 to provide a good and much cheaper alternative to the uncompressed D1 format.Betacam SX (1996) was a digital tape recording format which uses a constrained versionof MPEG-2 compression at the 4:2:2 profile, Main Level (422P@ML). The compressionis 10:1 and uses a 2-frame GOP (one I and one B frame), making it more difficult to edit.It uses half-inch tape cassettes.See also: MPEG-2B-framesSee MPEG-2BinaryMathematical 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 systemsand 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 number254 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 originalnumbers. 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 resultis always a 16-bit number. So, for full accuracy, all the resulting bits should be takeninto account. Multiplication is a very common process in digital television equipment(e.g. keying, mixes and dissolves).See also: Bit, Byte, Digital mixing, Dynamic Rounding31