sound.py 文件源码

def generate_chord(T=1,fs=44100,noise=True):
    """
    Generate random major chord with amplitude 1
    for duration T with sampling rate fs

    Return chord and label (pitch class)
    0  = Ab / G#
    1  = A
    2  = Bb / A#
    3  = B
    4  = C
    5  = Db / C#
    6  = D
    7  = Eb / D#
    8  = E
    9  = F
    10 = Gb / F#
    11 = G
    """
    t = np.linspace(0,T,T*fs)
    n1 = np.random.randint(1+17,88-10)
    chord_inversion = np.random.randint(1,6)
    n3 = 0  
    n5 = 0
    if chord_inversion == 1:
        n3 = n1 + 4
        n5 = n1 + 7
    if chord_inversion == 2:
        n3 = n1 + 7
        n5 = n1 + 16
    if chord_inversion == 3:
        n3 = n1 + -8
        n5 = n1 + 7
    if chord_inversion == 4:    
        n3 = n1 + -8
        n5 = n1 + -5
    if chord_inversion == 5:
        n3 = n1 + 4
        n5 = n1 + -5
    if chord_inversion == 6:
        n3 = n1 + -8
        n5 = n1 + -17
    f1 = 2**((n1-49)/12.0)*440
    f2 = 2**((n3-49)/12.0)*440
    f3 = 2**((n5-49)/12.0)*440

    phase1 = np.random.uniform(0, 2*np.pi, 1)
    phase2 = np.random.uniform(0, 2*np.pi, 1)
    phase3 = np.random.uniform(0, 2*np.pi, 1)
    label = (n1 % 12) + 1
    noise_var = np.random.uniform(0, 1, 1)

    sig = signal.square(f1*2*np.pi*t + phase1) + signal.square(f2*2*np.pi*t + phase2) + signal.square(f3*2*np.pi*t + phase3)
    if noise:
        sig = sig + noise_var*np.random.randn(int(T*fs))
    return sig/3, label-1