Light to Electricity: lines begin and end in black (low signal level) called Blanking between blanking is the active video scanning is precisely controlled by camera’s horizontal and vertical deflection circuits

Video Primary Colors: R G B three pick-up devices, transducers, one each for the primary colors which are optically separated by a prism each color signal is amplified and modified for display on CRT (gamma correction)

Color Matrix: R G B Matrix R, G and B signals are mathematically combined in the color matrix, producing: Y, the luminance signal, which approximates a monochrome camera output, made up of :.30R +.59G +.11B R-Y, and B-Y, the color difference signals

G Y R-Y B-Y Matrix R B Color Difference Signals:

Component vs Composite Video: R G B Y R-Y B-Y component systems uses three wires, one for each of Y, R-Y and B-Y BetaCam U-Matic R G B Y R-Y B-Y C SC + 90 º composite systems uses a single- wire feed of luminance with the modulated chroma added

Digital Basics: The primary digital devices are: the Analog-to-Digital converter; the A-D the Digital-to-Analog converter; the D-A some form of digital storage My assistant has in his hand the combination A-D and D-A converter he will be using to demonstrate the conversion process - a tape measure - and a digital storage device - a pad and pencil. With the help of his tape measure, he will perform an analog-to-digital conversion, then he will store the data in non-volatile memory and finally perform a digital-to-analog conversion to recreate the original analog signal.

Analog to Digital Conversion: Time AmplitudeAmplitude At precise time intervals we measure the amplitude of the analog signal.

Digital Storage: The numbers corresponding to those levels are recorded along with the order in which they were taken.

So, how did he do? original: raw: filtered:

digital performance is linked to two properties of the A-D and D-A conversion process: SAMPLING RATE - how often is the signal measured QUANTIZATION RATE - how many discreet levels can be measured and stored our example illustrates QUANTIZATION ERROR, too few discreet levels requiring rounding be used for values between those levels increasing the quantization rate helps at the expense of more expensive A-D and D-A converters and much larger amounts of storage space no number of levels will ever be free of quantization error because analog signals utilize an infinite number of amplitudes Not Very Good!

a large number of samples must be gathered per cycle of signal in order to capture the smoothness of an analog waveform CDs are processed at a rate of 44,100 samples per second and 65,536 discreet levels our example’s sampling rate is equivalent to a 5,500 Hz. tone reproduced from a CD many professional recording engineers are very unhappy with CD reproduction of frequencies above 8KHz - the point where just 5.5 samples are taken per cycle increasing the number of samples taken per unit time improves the conversion, again at the cost of more expensive A-D and D-A converters and much larger amounts of storage Sampling Errors:

sampling rate ratio YCR/CBYCR/CB pixel 1 pixel 2 pixel 3 pixel 4 pixel 5 pixel 6 pixel 7 pixel 8 line 1 line 2 line 3 line 4 4:2:0 4:2:0 samples C R and C B at 6.75MHz., just like in 4:2:2, but only for the ODD lines of the field or frame. During the EVEN lines, ONLY “Y” is sampled. The Chroma information is averaged over two luminance samples horizontally, and two adjacent lines vertically. 8bit 1 2 C R C B YYYYYYYY YYYYYYYY YYYYYYYY YYYYYYYY

Constant Bit Rate: Analog to Digital conversion produces constant bit rate (CBR) data. CD audio, silent or a symphony, produce identical file sizes dependant only on time. Full bit rate video is based on the number of samples taken and the bit-depth of the samples. 8 bit 4:2:2 component black is still 216Mb/s. 16 bits per second per channel X 44.1 K samples per second Kbits per second per channel X 2 channels (Left and Right) 1,411,200 bits per second 8 bits per sample X 13.5 M samples per second (Y) 108 Mbits per second (Y) 8 bits per sample X 6.25 M samples per second (R-Y) 54 Mbits per second (R-Y) 8 bits per sample X 6.25 M samples per second (B-Y) 54 Mbits per second (B-Y)