Add yin based pitch computation

TTS/utils/yin.py

@@ -0,0 +1,118 @@
+# adapted from https://github.com/patriceguyot/Yin
+
+import numpy as np
+
+
+def differenceFunction(x, N, tau_max):
+    """
+    Compute difference function of data x. This corresponds to equation (6) in [1]
+    This solution is implemented directly with Numpy fft.
+
+
+    :param x: audio data
+    :param N: length of data
+    :param tau_max: integration window size
+    :return: difference function
+    :rtype: list
+    """
+
+    x = np.array(x, np.float64)
+    w = x.size
+    tau_max = min(tau_max, w)
+    x_cumsum = np.concatenate((np.array([0.0]), (x * x).cumsum()))
+    size = w + tau_max
+    p2 = (size // 32).bit_length()
+    nice_numbers = (16, 18, 20, 24, 25, 27, 30, 32)
+    size_pad = min(x * 2 ** p2 for x in nice_numbers if x * 2 ** p2 >= size)
+    fc = np.fft.rfft(x, size_pad)
+    conv = np.fft.irfft(fc * fc.conjugate())[:tau_max]
+    return x_cumsum[w : w - tau_max : -1] + x_cumsum[w] - x_cumsum[:tau_max] - 2 * conv
+
+
+def cumulativeMeanNormalizedDifferenceFunction(df, N):
+    """
+    Compute cumulative mean normalized difference function (CMND).
+
+    This corresponds to equation (8) in [1]
+
+    :param df: Difference function
+    :param N: length of data
+    :return: cumulative mean normalized difference function
+    :rtype: list
+    """
+
+    cmndf = df[1:] * range(1, N) / np.cumsum(df[1:]).astype(float)  # scipy method
+    return np.insert(cmndf, 0, 1)
+
+
+def getPitch(cmdf, tau_min, tau_max, harmo_th=0.1):
+    """
+    Return fundamental period of a frame based on CMND function.
+
+    :param cmdf: Cumulative Mean Normalized Difference function
+    :param tau_min: minimum period for speech
+    :param tau_max: maximum period for speech
+    :param harmo_th: harmonicity threshold to determine if it is necessary to compute pitch frequency
+    :return: fundamental period if there is values under threshold, 0 otherwise
+    :rtype: float
+    """
+    tau = tau_min
+    while tau < tau_max:
+        if cmdf[tau] < harmo_th:
+            while tau + 1 < tau_max and cmdf[tau + 1] < cmdf[tau]:
+                tau += 1
+            return tau
+        tau += 1
+
+    return 0  # if unvoiced
+
+
+def compute_yin(sig, sr, w_len=512, w_step=256, f0_min=100, f0_max=500, harmo_thresh=0.1):
+    """
+
+    Compute the Yin Algorithm. Return fundamental frequency and harmonic rate.
+
+    :param sig: Audio signal (list of float)
+    :param sr: sampling rate (int)
+    :param w_len: size of the analysis window (samples)
+    :param w_step: size of the lag between two consecutives windows (samples)
+    :param f0_min: Minimum fundamental frequency that can be detected (hertz)
+    :param f0_max: Maximum fundamental frequency that can be detected (hertz)
+    :param harmo_tresh: Threshold of detection. The yalgorithmù return the first minimum of the CMND function below this treshold.
+
+    :returns:
+
+        * pitches: list of fundamental frequencies,
+        * harmonic_rates: list of harmonic rate values for each fundamental frequency value (= confidence value)
+        * argmins: minimums of the Cumulative Mean Normalized DifferenceFunction
+        * times: list of time of each estimation
+    :rtype: tuple
+    """
+
+    tau_min = int(sr / f0_max)
+    tau_max = int(sr / f0_min)
+
+    timeScale = range(0, len(sig) - w_len, w_step)  # time values for each analysis window
+    times = [t / float(sr) for t in timeScale]
+    frames = [sig[t : t + w_len] for t in timeScale]
+
+    pitches = [0.0] * len(timeScale)
+    harmonic_rates = [0.0] * len(timeScale)
+    argmins = [0.0] * len(timeScale)
+
+    for i, frame in enumerate(frames):
+        # Compute YIN
+        df = differenceFunction(frame, w_len, tau_max)
+        cmdf = cumulativeMeanNormalizedDifferenceFunction(df, tau_max)
+        p = getPitch(cmdf, tau_min, tau_max, harmo_thresh)
+
+        # Get results
+        if np.argmin(cmdf) > tau_min:
+            argmins[i] = float(sr / np.argmin(cmdf))
+        if p != 0:  # A pitch was found
+            pitches[i] = float(sr / p)
+            harmonic_rates[i] = cmdf[p]
+        else:  # No pitch, but we compute a value of the harmonic rate
+            harmonic_rates[i] = min(cmdf)
+
+    return pitches, harmonic_rates, argmins, times