MPEG - 1 Layer III 立體聲位元分配方法

Abstract

本篇論文提出了兩個分配位元給三種立體聲編碼模式的各聲道的方法，及對單迴圈位元分配方法的參數設計。兩個分配位元方法都是基於要使各聲道位元分配最佳化而提出。第一個方法利用合併兩聲道部份位元分配流程來保持兩聲道的品質相等，第二種則利用兩個聲道的能量比來預估各聲道所需要的位元。這兩種方法在MPEG - 1 Layer III的立體聲模式下，配合單迴圈位元分配的參數設計，可以得到較佳的品質。而在聯合立體聲模式下，加上對遮蔽能力計算的更動，可以得到0.5 ~ 2 dB品質上的改善。

Two methods for allocating bits to each channel in 3 stereo coding mode, and parameter design of single loop bit allocation is presented in this thesis. Two methods are proposed based on the criterion that optimize the bit allocation result of each channel. One using combine partial bit allocation process to keep quality of two channels equal. Another estimating bit requirement of each channel by energy ratio of two channels. In stereo mode of MPEG - 1 Layer III, with parameter design of single loop bit allocation, better quality is achieved. In other two coding mode of joint stereo, with modifying of masking ability, 0.5 ~ 2db quality improvement is achieved.