 Gary Sullivan

Gary Sullivan coauthored Recommended 8-Bit YUV Formats for Video Rendering by Gary Sullivan and Stephen Estrop with Stephen Estrop. Their technical article connects chroma subsampling, sample storage and conversion between the RGB color model and YCbCr.^[ref]

An original neutral-gray example isolates code range conversion from memory layout. Take eight-bit computer RGB inputs $(R,G,B)=(g,g,g)$, with codes from 0 to 255. Since the three coefficients in the guide's luma combination sum to one, the combined gray value is $g$ regardless of which of its two coefficient sets is selected. For its eight-bit nominal video coding, useThus gray 64 becomes $(Y,U,V)=(71,128,128)$, while gray 192 becomes $(181,128,128)$. The separation of the two stored luma codes is 110 rather than 128. These values follow the stipulated input/output ranges and nearest-integer rounding; copying an RGB component directly into the luma slot would implement a different mapping.^[ref]

Changing a pixel format can rearrange those same codes without performing this conversion. Conversely, converting every pixel's three components does not itself require chroma subsampling. Keeping these operations separate is a practical contribution of the jointly authored guide; no individual authorship of its formulas is inferred.