基于ARM的HE-AAC音频解码滤波器组的优化研究

发布时间：2018-04-15 00:32

  本文选题：HE-AAC + ARM　； 参考：《西安电子科技大学》2012年硕士论文

【摘要】：HE-AAC是目前最先进的感知音频编解码技术,它具有多声道、多采样率、高压缩比、高音质等特点,比AAC的效率提高30%。在许多领域得到广泛的应用,支持HE-AAC的消费电子产品成为电子市场需求的热点。 HE-AAC解码器中的滤波器组包含逆向改进余弦变换(IMDCT)、分析滤波器组和合成滤波器组三个模块。滤波器组的基本功能是允许信号的某一部分频率顺利通过,而另外一部分频率则受到较大抑制。滤波器组在整个音频编解码系统中,运算量占60%以上,具有很重要的作用。随着音频解码技术的不断提高,滤波器组的研究也越来越深。 本文主要研究基于ARM的HE-AAC音频解码滤波器组的优化。首先对HE-AAC音频标准里的三个滤波器组模块的原始算法作了分析,然后分别采用基4IFFT算法、DCT-Ⅲ算法、DCT-Ⅲ和DCT-Ⅱ的组合算法优化IMDCT模块、分析滤波器组以及合成滤波器组。其次,针对ARM平台的特点,依据定点实现原理,对滤波器组进行定点转换。最后在ARM平台上利用NEON语法的优势,分别实现了上述三个优化算法,并对滤波器组在寄存器分配、函数参数、循环变量、函数调用、除法运算、乘法移位运算、通用数据处理、加载/存储数据等方面进行了改进。经过NEON语法优化后的滤波器组比C语言和ARMv6语法优化的代码大小都小,使得存储器的使用大大减少了。并且在系统运行后,通过了HE-AAC音频标准规定的Conformance测试,提高了解码效率。
[Abstract]:HE-AAC is the most advanced perceptual audio coding and decoding technology. It has the characteristics of multi-channel, multi-sampling rate, high compression ratio, high sound quality and so on. It is 30 times more efficient than AAC.It has been widely used in many fields, and consumer electronics supporting HE-AAC has become a hot spot in electronic market.The filter banks in HE-AAC decoder include three modules: inverse improved cosine transform (HE-AAC), filter bank and composite filter bank.The basic function of the filter bank is to allow one part of the signal to pass smoothly, while the other part is greatly suppressed.In the whole audio coding and decoding system, the filter bank accounts for more than 60% of the computation, which plays an important role.With the improvement of audio decoding technology, the research of filter banks is becoming more and more deep.This paper focuses on the optimization of HE-AAC audio decoding filter banks based on ARM.Firstly, the original algorithm of three filter banks in HE-AAC audio standard is analyzed, then the combination algorithm of DCT- 鈪，

本文编号：1751740