Exploration of Practical HEVC/H.265 Sample Adaptive Offset Encoding Policies

A new in-loop filter, sample adaptive offset (SAO) allows the latest video compression standard, HEVC or H.265, to achieve higher coding efficiency both in objective and subjective measures. However, it requires additional operations to estimate the best SAO parameters per coding tree unit (CTU) during the video encoding process, which often leads to many practical issues such as high computational complexity or architectural inefficiency that might not be affordable for low power or real-time video encoders. In this paper, we explore various SAO encoding policies including complexity reduction in the SAO parameter estimation and efforts to remove inefficiency caused by its implementation in a pipelined manner through numerous experimental tests.