For sample adaptive offset, classification may be used to classify the pixels into multiple
categories and pixels in each category are offset compensated using an offset value for the
category. The classification may be based on values of the current pixel and its neighboring
pixels before SAO compen sation. Therefore, the SAO compensated pixel cannot be writ ten
back to the current pixel location until the category for all pixels are determined. An
embodiment of the present inven tion stores the relation between the current pixel and said …

(57) ABSTRACT A method and apparatus for sample adaptive offset (SAO) compensation of
reconstructed video data are disclosed. In one embodiment, the relation between the current
pixel and said one or more neighboring pixels is stored so that the SAO compensated
current pixel can replace the current pixel without buffering the to-be-processed pixels for
classifica tion. The SAO process may be performed on a region by region basis to adapt to
the local characteristics of the picture.