Hardware-Oriented Early Detection Algorithms for 44 and 88 All-Zero Blocks in H.264

Yiqing HUANG
Satoshi GOTO

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E92-A    No.4    pp.1063-1071
Publication Date: 2009/04/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E92.A.1063
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Advanced Technologies Emerging Mainly from the 21st Workshop on Circuits and Systems in Karuizawa)
all-zero block,  early detection,  sum of absolute difference,  hardware-oriented,  H.264,  

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H.264 is the latest HDTV video compression standard, which provides a significant improvement in coding efficiency at the cost of huge computation complexity. After transform and quantization, if all the coefficients of the block's residue data are zero, this block is called all-zero block (AZB). Provided that an AZB can be detected early, the process of transform and quantization on an AZB can be skipped, which reduces significant redundant computations. In this paper, a theoretical analysis is performed for the sufficient condition for AZB detection. As a result, a partial sum of absolute difference (SAD) based 44 AZB detection algorithm is derived. And then, a hardware-oriented AZB detection algorithm is proposed by modifying the order of SAD calculation. Furthermore, a quantization parameter (QP) oriented 88 AZB detection algorithm is proposed according to the AZB's statistical analysis. Experimental results show that the proposed algorithm outperforms the previous methods in all cases and achieves major improvement of computation reduction in the range from 6.7% to 42.3% for 44 blocks, from 0.24% to 79.48% for 88 blocks. The computation reduction increases as QP increases.