AAC编码算法的快速实现

Fast Implementation of AAC Encoder

Advanced Audio Coding(AAC)是一种高质量的音频编码标准,其编码算法的运算复杂度很高。本文针对AAC的心理声学模型谱估计采用SDFT'谱代替标准建议的DFI'谱,对其比特分配模块则提出了一种自适应的最佳全局量化阶搜索方法,此外,还采用基于FFT的MDC'I'快速算法,大大降低了AAC编码算法的运算复杂度。

AAC (Advanced Audio Coding) is a high quality audio coding standard. The real-time realization of AAC encoder is very difficult, because the coding algorithm is too complex. Some improvements of AAC are made in this paper, which are mostly concentrated on the decreasing of the computational complexity. The improvements are as followings: using SDFT as the base of the psychoacoustic model instead of DFT, implementing an adaptive algorithm in searching the global quantization step, and also a FFT based fast algorithm of MDCT is presented. The improvements greatly reduced the encoding time that the AAC encoder needs.