H.264中全零块预判的新方法

Novel early detection of method of all-zero DCT coefficients in H.264

为了避免全零DCT（离散余弦变换）系数进行变换与量化产生的冗余计算，从H．264中的DCT公式与量化原理出发，结合视频图像残差系数的分布规律，在分析现有算法存在的误判与漏判的基础上，提出了一种预先判断全零DCT系数块的方法。实验结果表明，与文献中的经典算法相比较，新提出的方法应用在中低比特率的视频序列中可以减少12％～37％的平均编码时间，平均压缩率提高了6％～10％。

An innovative algorithm for detecting all-zero discrete cosine transform （DCT） coefficient blocks prior to DCT and quantization forvideocodingstandardofH.264/AVCispresented. A mathematic model for predetermination is established based on the characteristics of float/integer DCT formula and quantization, the distribution of the residual pixel values, analysis of the false-judgment and miss-judgment of prevent algorithms. The simulation results show that compared to conventional methods, the proposed algorithm achieves averagely an 12%-37% encoding time saving and an 6%-10% improvement of compression rate with a little PSNR loss for low or middle bit-rate video sequences.