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Tektronix provides test and measurement instruments, solutions and services for the computer, semiconductor, military/aerospace, consumer electronics and education industries worldwide.
Discontinued analogue circuit based Tektronix test signal generator that is used to generate full field composite analogue test signals. Replaced by the Tektronix TSG-170A.
Industry:Entertainment
A bitstream which contains only Main Profile, High Level (or simpler) video at 25 Hz or 50 Hz frame rates.
Industry:Entertainment
An IRD (Integrated Receiver Decoder) that is capable of decoding and displaying pictures based on a nominal video frame rate of 25 Hz or 50 Hz from MPEG-2 Main Profile, High Level bitstreams, in addition to providing the functionality of a 25 Hz SDTV IRD.
Industry:Entertainment
A bitstream which contains only Main Profile, Main Level video at 25 Hz frame rate.
Industry:Entertainment
An IRD (Integrated Receiver Decoder) which is capable of decoding and displaying pictures based on a nominal video frame rate of 25 Hz from MPEG-2 Main Profile, Main Level bitstreams.
Industry:Entertainment
A film image scanned into a computer file at a resolution of 2048 horizontal pixels per line.
Industry:Entertainment
The international standard CCIR-601-1 specifies eight-bit digital coding for component video, with black at luma code 16 and white at luma code 235, and chroma in eight-bit two's complement form centred on 128 with a peak at code 224. This coding has a slightly smaller excursion for luma than for chroma: luma has 219 risers compared to 224 for Cb and Cr. The notation CbCr distinguishes this set from PbPr where the luma and chroma excursions are identical. For Rec. 601-1 coding in eight bits per component, Y_8b = 16 + 219 * Y Cb_8b = 128 + 112 * (0.5/0.886) * (Bgamma - Y) Cr_8b = 128 + 112 * (0.5/0.701) * (Rgamma - Y) Some computer applications place black at luma code 0 and white at luma code 255. In this case, the scaling and offsets above can be changed accordingly, although broadcast-quality video requires the accommodation for headroom and footroom provided in the CCIR-601-1 equations. CCIR-601-1 Rec. calls for two-to-one horizontal subsampling of Cb and Cr, to achieve 2/3 the data rate of RGB with virtually no perceptible penalty. This is denoted 4:2:2. A few digital video systems have utilised horizontal subsampling by a factor of four, denoted 4:1:1. JPEG and mpeg normally subsample Cb and Cr two-to-one horizontally and also two-to-one vertically, to get 1/2 the data rate of RGB. No standard nomenclature has been adopted to describe vertical subsampling. To get good results using subsampling you should not just drop and replicate pixels, but implement proper decimation and interpolation filters. YCbCr coding is employed by D-1 component digital video equipment.
Industry:Entertainment
Kodak's PhotoYCC colour space (for PhotoCD) is similar to YCbCr, except that Y is coded with lots of headroom and no footroom, and the scaling of Cb and Cr is different from that of Rec. 601-1 in order to accommodate a wider colour gamut: Y_8bit = (255/1.402) * Y C1_8bit = 156 + 111.40 * (Bgamma - Y) C2_8bit = 137 + 135.64 * (Rgamma - Y) The C1 and C2 components are subsequently subsampled by factors of two horizontally and vertically, but that subsampling should be considered a feature of the compression process and not of the colour space.
Industry:Entertainment
The U and V signals above must be carried with equal bandwidth, albeit less than that of luma. However, the human visual system has less spatial acuity for magenta-green transitions than it does for red-cyan. Thus, if signals I and Q are formed from a 123 degree rotation of U and V respectively (sic), the Q signal can be more severely filtered than I (to about 600 kHz, compared to about 1.3 MHz) without being perceptible to a viewer at typical TV viewing distance. YIQ is equivalent to YUV with a 33 degree rotation and an axis flip in the UV plane. The first edition of W.K. Pratt "Digital Image Processing", and presumably other authors that follow that bible, has a matrix that erroneously omits the axis flip; the second edition corrects the error. Since an analogue NTSC decoder has no way of knowing whether the encoder was encoding yuv or YIQ, it cannot detect whether the encoder was running at 0 degree or 33 degree phase. In analogue usage the terms YUV and YIQ are often used somewhat interchangeably. YIQ was important in the early days of NTSC but most broadcasting equipment now encodes equiband U and V. The D-2 composite digital DVTR (and the associated interface standard) conveys ntsc modulated on the YIQ axes in the 525-line version and pal modulated on the YUV axes in the 625-line version.
Industry:Entertainment
If three components are to be conveyed in three separate channels with identical unity excursions, then the Pb and Pr colour difference components are used: Pb = (0.5/0.886) * (Bgamma - Y) Pr = (0.5/0.701) * (Rgamma - Y) These scale factors limit the excursion of EACH colour difference component to -0.5 .. +0.5 with respect to unity Y excursion: 0.886 is just unity less the luma coefficient of blue. In the analogue domain Y is usually 0 mV (black) to 700 mV (white), and Pb and Pr are usually +- 350 mV. YPbPr is part of the CCIR Rec. 709 HDTV standard, although different luma coefficients are used, and it is denoted E'Pb and E'Pr with subscript arrangement too complicated to be written here. YPbPr is employed by component analogue video equipment such as M-II and BetaCam; Pb and Pr bandwidth is half that of luma.
Industry:Entertainment
