Transform and quantization account for a considerable amount of computation time in video encoding process. However, there are a large number of discrete cosine transform coefficients which are finally quantized into zeros. In essence, blocks with all zero quantized coefficients do not transmit any information, but still occupy substantial unnecessary computational resources. As such, detecting all-zero block (AZB) before transform and quantization has been recognized to be an efficient approach to speed up the encoding process. Instead of considering the hard-decision quantization (HDQ) only, in this paper, we incorporate the properties of soft-decision quantization into the AZB detection. In particular, we categorize the AZB blocks into genuine AZBs (G-AZB) and pseudo AZBs (P-AZBs) to distinguish their origins. For G-AZBs directly generated from HDQ, the sum of absolute transformed difference-based approach is adopted for early termination. Regarding the classification of P-AZBs which are generated in the sense of rate-distortion optimization, the rate-distortion models established based on transform coefficients together with the adaptive searching of the maximum transform coefficient are jointly employed for the discrimination. Experimental results show that our algorithm can achieve up to 24.16% transform and quantization time-savings with less than 0.06% RD performance loss. The total encoder time saving is about 5.18% on average with the maximum value up to 9.12%. Moreover, the detection accuracy of larger TU sizes, such as $16times 16$ and $32times 32$ can reach to 95% on average.

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classification of pazbs harddecision quantization hdq 16times 16 rd performance transform and quantization timesavings video encoding discrete cosine transform coefficients maximum transform coefficient termination encoder time saving allzero block azb before transform adaptive searching gazbs ratedistortion models detection accuracy sum of absolute transformed differencebased approach 32times

Jing CuiRuiqin XiongXinfeng ZhangShiqi WangShanshe WangSiwei MaWen Gao,.Hybrid All Zero Soft Quantized Block Detection for HEVC. 27 (10),4987-5001.

Jing CuiRuiqin XiongXinfeng ZhangShiqi WangShanshe WangSiwei MaWen Gao,"Hybrid All Zero Soft Quantized Block Detection for HEVC" 27

Jing CuiRuiqin XiongXinfeng ZhangShiqi WangShanshe WangSiwei MaWen Gao,"Hybrid All Zero Soft Quantized Block Detection for HEVC"