chromagram.py 文件源码

def CQT_slow(x, fs, bins, fmin, fmax):

    K = int(bins*np.ceil(np.log2(fmax/fmin)))
    Q = 1/(2**(1/bins)-1)
    cqt = np.zeros(K, dtype = np.complex)

    for k in range(K):
        fk = (2**(k/bins))*fmin
        N = int(np.round(Q*fs/fk))
        arr = -2*np.pi*1j*Q*np.arange(N)/N 
        cqt[k] = np.dot(x[:N], np.transpose(hamming(N) * np.exp(arr)))/N 
    return cqt