基于音调调整的AVS-P10带宽扩展优化方案

Optimized Bandwidth Extension Scheme of AVS-P10 Based on Tonality Adjustment

AVS-P10是低码率带宽扩展方案的国家标准,但其仅利用高频包络信息和高频增益调整还原信号的高频部分,导致还原音质较差。为此,在研究AVS-P10带宽扩展原理的基础上,提出一种基于音调调整的带宽扩展优化方案。在编码端通过快速傅里叶变换域提取音调参数,在解码端根据音调参数对高频陡峭的峰和谷做精细调整,使重建后的谱包络结构更接近原始语音。实验结果表明,该方案在重建音质上相较于原AVS-P10标准,客观评价指标ODG得分提高9. 4%,主观评价指标CMOS得分提高1. 14分,还原音质有明显改善。

AVS-P10 is a national standard for low bit rate bandwidth extension schemes,but since the standard only uses the high frequency envelope information and the high frequency gain to adjust the high frequency portion of the restored signal,the restored sound quality is poorer.Aiming at this problem,after analyzing the corresponding bandwidth extension principle of AVS-P10,a novel bandwidth extension scheme based on tonality adjustment is proposed.Tonality parameters are extracted from the encoder part in Fast Fourier Transform(FFT)domain,which are recovered to adjust the steep peaks and dips in decoder.Experimental results show that,compared with AVS-P10 standard,the proposed scheme can improve the ODG score by 9.4%with the objective judgement test,and the CMOS score by 1.14 with the subjective test part,which concludes that the reconstructed audio quality is improved.