计算得到的瞬时频率(作为采样率的比例)作为复谱相位的时间导数。参考文献：Abe, Toshihiko, Takao Kobayashi, and Satoshi Imai. “Harmonics tracking and pitch extraction based on instantaneous frequency.” International Conference on Acoustics, Speech, and Signal Processing, ICASSP-95., Vol. 1. IEEE, 1995.
cqt()
常数Q变换，参考文献：Schoerkhuber, Christian, and Anssi Klapuri. “Constant-Q transform toolbox for music processing.” 7th Sound and Music Computing Conference, Barcelona, Spain. 2010.
icqt()
常数Q逆变换
hybrid_cqt()
计算音频信号的混合常量- q变换。
pseudo_cqt()
计算音频信号的伪常量- q变换。
iirt()
使用IIR滤波器的时频表示。参考文献：Müller, Meinard. “Information Retrieval for Music and Motion.” Springer Verlag. 2007.
fmt()
快速梅林变换(FMT)。参考文献：【1】De Sena, Antonio, and Davide Rocchesso. “A fast Mellin and scale transform.” EURASIP Journal on Applied Signal Processing 2007.1 (2007): 75-75.【2】Cohen, L. “The scale representation.” IEEE Transactions on Signal Processing 41, no. 12 (1993): 3275-3292.
色谱能量归一化。具体内容需参考文献：Meinard Müller and Sebastian Ewert “Chroma Toolbox: MATLAB implementations for extracting variants of chroma-based audio features” In Proceedings of the International Conference on Music Information Retrieval (ISMIR), 2011.
melspectrogram()
计算梅尔频谱
mfcc()
梅尔倒频谱系数
rms()
谱的均方根
spectral_centroid()
谱中心
spectral_bandwidth()
谱带宽。
spectral_contrast()
谱对比度，参考文献：Jiang, Dan-Ning, Lie Lu, Hong-Jiang Zhang, Jian-Hua Tao, and Lian-Hong Cai. “Music type classification by spectral contrast feature.” In Multimedia and Expo, 2002. ICME‘02. Proceedings. 2002 IEEE International Conference on, vol. 1, pp. 113-116. IEEE, 2002.
spectral_flatness()
频谱平坦度
spectral_rolloff()
滚降频率
poly_feature()
求一个n阶多项式与谱图列的拟合系数
tonnetz()
计算色调质心特征(tonnetz)，详见参考文献：Harte, C., Sandler, M., & Gasser, M. (2006). “Detecting Harmonic Change in Musical Audio.” In Proceedings of the 1st ACM Workshop on Audio and Music Computing Multimedia (pp. 21-26). Santa Barbara, CA, USA: ACM Press. doi:10.1145/1178723.1178727.
zero_crossing_rate()
过零率
Rhythm features
函数名称
功能
tempogram()
计算模板图:起始强度包络线的局部自相关。参考文献：Grosche, Peter, Meinard Müller, and Frank Kurth. “Cyclic tempogram - A mid-level tempo representation for music signals.” ICASSP, 2010.
Filtering by nearest-neighbors.参考文献【1】Buades, A., Coll, B., & Morel, J. M. (2005, June). A non-local algorithm for image denoising. In Computer Vision and Pattern Recognition, 2005. CVPR 2005. IEEE Computer Society Conference on (Vol. 2, pp. 60-65). IEEE.【2】Rafii, Z., & Pardo, B. (2012, October). “Music/Voice Separation Using the Similarity Matrix.” International Society for Music Information Retrieval Conference, 2012.