说明：  Mel-frequency cepstral coefficients (MFCCs) are coefficients that collectively make up an MFC. They are derived a type of cepstral representation of the audio clip (a nonlinear spectrum-of-a-spectrum ). The difference between the cepstrum and the mel-frequency cepstrum is that in the MFC, the frequency bands are equally spaced on the mel scale, which approximates the human auditory system s response more closely than the linearly-spaced frequency bands used in the normal cepstrum.