AC-3编码器中的高效比特分配算法

High Efficient Algorithm of the Bit Allocation in AC-3 Encoder

基于对信噪比偏移量的定量分析,得出待分配比特数与信噪比偏移量之间的理论估算公式,从而能够有效逼近信噪比偏移量的最佳值.在此基础上提出了一种基于一次逼近和收敛控制的高效比特分配算法,分别以迭代次数和剩余比特2个参数来衡量比特分配的效率和精度.实验结果表明,该算法所需的平均搜索次数约为传统算法的71.4%,使得AC-3编码器比特分配的精度和效率均有明显提升.

In this paper,based on the quantitative analysis of the snroffset,a formula which can estimate the relation between the volume of bit allocation and the volume of snroffset was obtained. By employing this formula,the optimal value of snroffset can be approached effectively. Based on the deduction,a high efficient algorithm of the bit allocation by one rough approaching and the convergence control was proposed. The accuracy and efficiency of bit allocation were measured by the times of iteration and the value of bitleft, respectively. Experimental results show that the average search times are only about 71.4% of those of the traditional algorithm. This algorithm can greatly enhance both the accuracy and efficiency of the bit allocation in AC-3 encoder.