An adaptive and low-complexity all-zero block detection for HEVC encoder

To improve the detection accuracy of SAD or SATD based threshold and save the time cost of RDO determination, we proposed an All Zero Block (AZB) detection method by adaptively searching the maximum transform coefficient amplitude in low frequency of TU after conventional SATD detection was failed. The experimental results show that our algorithm can achieve around 39% transform and quantization time-saving with only 0.1% on average RD performance reduction. The detection accuracy of larger TU size, i.e. 16×16 and 32 × 32, can reach up to about 95% on average.