Method and apparatus for real-time SAO parameter estimation

A method to encode video input data using a sample adaptive offset (SAO) video encoder, the method comprising:

• receiving a set of original pixels at a first input of the SAO video encoder;
• receiving a set of deblocked pixels at a second input of the SAO video encoder;
• for a plurality of categories that includes band categories and edge categories, categorizing each of the deblocked pixels into at least one band category and into at least one edge category;
• after categorizing each of the deblocked pixels, for each category:
• determining a count of deblocked pixels in the category;
• estimating an error based on a difference between a deblocked pixel of the set of deblocked pixels and a corresponding original pixel of the set of original pixels;
• determining a set of candidate offsets associated with the category, wherein each candidate offset of the set of candidate offsets is a value ranging from a minimum offset and a maximum offset;
• estimating a rate distortion (RD) cost associated with each candidate offset of the set of candidate offsets for the category;
• and
• determining a minimum RD cost of the estimated RD costs for the category;
• and
• using the minimum RD cost for each category to encode the video input data.