Multi-Sinusoidal Excitation Model in Audio Coding

• Main Authors: Li-Wei Wang, 王禮瑋
• Other Authors: Wen-Whei Chang
• Format: Others
• Language: en_US
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/37237233673152760964

碩士 === 國立交通大學 === 電信研究所 === 81 === Current research on high-quality audio coding focuses on either subband or transform coding whereby the masking effect is exploited in dynamic bit allocation to result in an inaudible noise spectrum. However, the frequency-domain coding approaches consume heavy computations and the redundancy remains to be removed further. On the other hand, time-domain coders have the potential to achieve transparent reproduction by incorporating an appropriate excitation structure. In this thesis, we propose a multi-sinusoids excitation structure which consists of the sum of gain-scaled sinusoidal functions, rather than the white noise as in Code-Excited LPC (CELP). The performance results show significant improvement not only in the conventional distortion measure such as SNR and segSNR, but also in the newly proposed objective quality measure called generalized bark spectral distortion (GBSD). Further more, a multi- sinusoids excitation structure also simplifies the computation load in about 90 times.