MPEG層次三之新位元分配方法

Abstract

因為MPEG層次三在低位元數具有高品質，而已經廣泛地在消費性電子 、通訊和廣播上。由於層次三的編碼器包含了位元分配器，造成計算複雜 度遠大於解碼器。在本篇論文，在立體聲中，我們提出三個有效率的位元 分配方法，並且擴充到集中式立體聲的位元分配方法。 本篇論文經由 四個方面考慮有效率的位元分配方法。首先，使用泰勒展開式估測非均勻 性量化器的噪音能量。第二，利用統計方法，預估位元數。第三，使用迴 覆式技巧做位元分配。第四，將位元分配方法擴充到集中式立體聲編碼上 。 新的位元分配方法，在速度上，比MPEG層次三快十倍。在品質上， 則提供更好的品質。在集中式立體聲中，新的位元分配方法在高壓縮率下 ，可以得到不錯品質改進。 MPEG Layer III has been widely used in consumer electronics, telecommunicationsand the broadcasting because it has high quality in low bit rate. The encoderof MPEG Layer III contains the bit allocation. That makes the computer complexity of the encoder higher than that of decoder. In this thesis, we present three efficient bit allocation methods in the stereo coding. Also weextend these methods to the intensity stereo coding. This thesis considers the efficient bit allocation through four aspects. First,we apply the Taylor formula to estimates the energy of noise in nonuniform uantizer. Second, we predict the bit number through the statistical approach.Third, we develop an efficient iterative approach of the bit allocation for thestereo coding. Forth, the efficient approach has been extended to the intensitystereo coding. The new bit allocation methods are ten times faster than that in the draft ofMPEG LayerIII. The new bit allocation methods provide the better quality than that in traditional method. In the intensity coding, the new bit allocationmethod promises that there are transparent qualities in the left and rightchannels.