mplified to: RGB-YCbCr Equations: HDTV R' = Y + 1.371 (Cr - 128) G' = Y - 0.698(Cr - 128) - 0.336(Cb - 128) RGB to YCbCr: Analog Equations B' = Y + 1.732(Cb - 128) Many specifications assume the source is analog R'G'B' with a normalized range of 0-1. This is first converted to YCbCr to RGB: General Considerations analog YPbPr: When performing YCbCr to R'G'B' conversion, the Y = 0.213R' + 0.715G' + 0.072B resulting R'G'B' values have a nominal range of 16-235, Pb = -0.115R" - 0.385G' + 0.500B' with possible occasional excursions into the 0-15 and Pr = 0.500R' - 0.454G' - 0.046B 236-255 values. This is due to Y and CbCr occasionally To generate 8-bit YCbCr with the proper values, going outside the 16-235 and 16-240 ranges, re- YPbPr is then quantized to 8 bits: spectively, due to video processing and noise. Note that 8-bit YCbCr and R'G'B' data should be saturated at the Y = round [219Y + 16] 0 and 255 levels to avoid underflow and overflow wrap- Cb = round [224Pb + 128] around problems. Cr = round [224Pr + 128] Table 7.2-2 lists the YCbCr values for 75% ampli- tude, 100% saturated color bars, a common video test RGB to YCbCr: Digital Equations signal. To convert 8-bit digital R'G'B' data with a 16-235 nominal range (Studio R'G'B') to YCbCr, the analog Computer Systems Considerations equations may be simplified to: If the R'G'B' data has a range of 0-255, as is commonly Y = 0.213R' + 0.715G' + 0.072B found in computer systems, the following equations may Cb = -0.117R'-0.394G - + 0.511B' + 128 be more convenient to use: Cr = 0.511R" - 0.464G' - 0.047B + 128 Y = 0.257R' + 0.504G' + 0.098B + 16 Cb = -0.148R' - 0.291G' + 0.439B' + 128 YCbCr to RGB: Analog Equations Cr = 0.439R' - 0.368G' - 0.071B + 128 Many specifications assume the source is analog YPbPr. R' = 1.164(Y - 16) + 1.596(Cr - 128) This is first converted to analog R'G'B': G' = 1.164(Y - 16) - 0.813(Cr - 128) R' = Y + 1.575Pr -0.391(Cb - 128) G' = Y - 0.468Pr - 0.187Pb B' = 1.164(Y - 16) + 2.018(Cb - 128) B' = Y + 1.856Pb Table 7.2-2 75% YCbCr color bars. No