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It is frequently necessary to convert between YUV pixel formats (used by the JPEG and MPEG compression methods) and RGB format (used by many hardware manufacturers.) The following formulas show how to compute a pixel's value in one format from the pixel value in the other format.
YUV format allows for higher compression rates without a proportionately high loss of data, as the U and V portions can be highly compressed and computed from the non- or lowly-compressed Y portion.
Computing YUV from RGB
Y = 0.3R + 0.6G + 0.1B U = B - Y V = R - Y
or
Y = 0.3R + 0.6G + 0.1B U = -0.3R - 0.6G + 0.9B V = 0.7R - 0.6G - 0.1B
Computing RGB from YUV
R = Y + V G = Y - 0.166667U - 0.5V B = Y + U
Note All units range from 0 (zero) to 1.0 (one). In DirectDraw, they range from 0 to 255. Overflow and underflow can (and does) occur, and the results must be saturated.
Last updated on Tuesday, May 18, 2004