Abstract:

When using ISO standard of perceptual noise substitution (PNS) algorithm in advanced audio coding(AAC), it seems to cause misjudgment when detecting the noise, and results in quality deterioration of coded audio. A new noise detection algorithm is proposed to solve the problem. It employs the characteristic of noise spectrum that is more flat than tone spectrum, and sets the dual threshold for the frames and scaling factor bands to detect the noise accurately. In addition, precoding module is added into the PNS module to further improve the coding efficiency of PNS. Experiments show that, compared with standard algorithm, the proposed greatly did improve the accuracy of noise detection, and obtain higher coding efficiency without any increase in coding complexity.

Key words: internal antenna, multi;audio signal, advanced audio coding, perceptual noise substitution, noise detection