基于能量守恒全零DCT系数块的预先判别算法

Early detection of all-zero DCT coefficient blocks based on energy conservation

针对全零DCT系数块,为避免对其进行变换和量化操作以减少编码器的运算量,从DCT公式、量化和能量守恒出发,在分析现有判别法对全零DCT系数块的误判与漏判的基础上,提出了一种预先判断全零DCT系数块的新方法,可应用于基于块的视频编码器中。同时,结合H.264整数变换和量化的特点对该算法进行了改进和仿真实验。实验结果表明,新提出的算法在保持PSNR不变的情况下,较现有典型方案有高出达32%的检出率,因而可更大幅度地降低DCT变换量化模块的计算复杂度。

In order to reduce the coding computation complexity of the DCT and quantization module, an innovative algorithm is presented for detecting all-zero Discrete Cosine Transform （DCT） coefficient blocks prior to DCT and quantization for all block-based video coding standards. This is a so-called early algorithm for detection all-zero DCT coefficients block （AZB）. A mathematic model for predetermination of AZB is established based on analysis of the false-judgment and miss-judgment of the existing algorithms, Paseval energy conservation theorem, and the characteristics of float/integer DCT formula and quantization. The algorithm is applied to H.264/AVC video coder JM98, and experimental results show that the proposed algorithm achieves detection ratio up to 320 higher than that of existing methodologies and reduces the computation complexity.