Adaptive threshold for AVS all-zero block detection

By eliminating the matrix of scaling factors in the transform and quantization, the paper derives the best AVS zero-block detection threshold relating only with the quantization parameter (QP). To improve the low detection capability of the fixed threshold, the paper proposes adaptive threshold for all-zero block detection. The algorithm uses the correlation of neighboring blocks to dynamical change the threshold. Experimental results show that the fixed threshold algorithm can achieve major improvement of computation reduction from 10.32%-40.06% and the adaptive threshold algorithm can get up to 2.12% to 10.76% of encoding time reduction versus the fixed threshold algorithm.