Optimized Design Of Audio Perceptual Coding Algorithm On AAC

With the rapidly development of network information and multimedia technology, the multimedia business need more and more pressing by people, multimedia and computer network technology already seeped to society economy and all aspects of life. In order to facilitate the storage and transmission, the perceptual audio coding technology based on psychoacoustic model is applied widely.Advanced audio coding (Advanced Audio Coding, referred to as AAC) is the most advanced perceptual audio coding technology currently, its advantages are mainly embodied in the following three aspects:the signal with a higher compression ratio, a modular quantization coding and decoding process, and perfect transparent reconstruction quality. AAC is richly endowed by nature as well as its potential market value, as a kind of audio coding standard is widely used in various fields But AAC standard algorithms also exist deficiencies, such as its complexity is very high, also, consuming a large amount of computing time and system resources exists certain coding delay, so is not conducive to the perceptual audio coding technology of real-time requirements. According to the experimental research, AAC encoding process in system resource consumption and operation cost are mainly concentrated in the quantization with coding, psychoacoustic model, filter and encoder each main module.In order to achieve a low complexity and high efficiency audio codec, also, in high efficiency while achieving perfect transparent reconstruction quality, this paper makes full use of perceptual audio core theory and reflection psychoacoustic model, by using objective parameters reflect the subjective auditory effects, and the quantization process pre-echo problems, the author proposed an adaptive window switching algorithm based on the dynamic block. The new algorithm uses a dynamic block concept, according to different sampling rate of audio signals using different blocking effect, combined with psychoacoustic model in time domain masking effect, so we could get more accurately in the transient signal and get reasonable window switches, also, the echo control and elimination in the time domain, in order to achieve the quantization noise generated can not be perceived, to achieve high efficiency, high fidelity audio coding effect. The algorithm reduced the algorithm complexity and the coding time, under the audio reconstruction in the premise of quality,...