Add amplitude parameter to sonify.pitch_contour

mir_eval/sonify.py

@@ -184,8 +184,8 @@ def __interpolator(x):
     return output
 
 
-def pitch_contour(times, frequencies, fs, function=np.sin, length=None,
-                  kind='linear'):
+def pitch_contour(times, frequencies, fs, amplitudes=None, function=np.sin,
+                  length=None, kind='linear'):
     '''Sonify a pitch contour.
 
     Parameters
@@ -200,6 +200,10 @@ def pitch_contour(times, frequencies, fs, function=np.sin, length=None,
     fs : int
         desired sampling rate of the output signal
 
+    amplitudes : np.ndarray
+        amplitude measurments, nonnegative
+        defaults to ``np.ones((length,))``
+
     function : function
         function to use to synthesize notes, should be :math:`2\pi`-periodic
 
@@ -208,7 +212,7 @@ def pitch_contour(times, frequencies, fs, function=np.sin, length=None,
         defaults to ``max(times)*fs``
 
     kind : str
-        Interpolation mode for the frequency estimator.
+        Interpolation mode for the frequency and amplitude values.
         See: ``scipy.interpolate.interp1d`` for valid settings.
 
     Returns
@@ -233,8 +237,17 @@ def pitch_contour(times, frequencies, fs, function=np.sin, length=None,
     # Estimate frequency at sample points
     f_est = f_interp(np.arange(length))
 
+    if amplitudes is None:
+        a_est = np.ones((length, ))
+    else:
+        # build an amplitude interpolator
+        a_interp = interp1d(
+            times * fs, amplitudes, kind=kind,
+            fill_value=0.0, bounds_error=False, copy=False)
+        a_est = a_interp(np.arange(length))
+
     # Sonify the waveform
-    return function(np.cumsum(f_est))
+    return a_est * function(np.cumsum(f_est))
 
 
 def chroma(chromagram, times, fs, **kwargs):

tests/test_sonify.py

@@ -72,6 +72,7 @@ def test_pitch_contour():
     noise = scipy.ndimage.gaussian_filter1d(np.random.randn(len(times)),
                                             sigma=256)
     freqs = 440.0 * 2.0**(16 * noise)
+    amps = np.linspace(0, 1, num=5 * fs, endpoint=True)
 
     # negate a bunch of sequences
     idx = np.unique(np.random.randint(0, high=len(times), size=32))
@@ -95,3 +96,9 @@ def test_pitch_contour():
     x = mir_eval.sonify.pitch_contour(times + 5.0, freqs, fs, length=fs * 7)
     assert len(x) == fs * 7
     assert np.allclose(x[:fs * 5], x[0])
+
+    # Test with explicit amplitude
+    x = mir_eval.sonify.pitch_contour(times, freqs, fs, length=fs * 7,
+                                      amplitudes=amps)
+    assert len(x) == fs * 7
+    assert np.allclose(x[0], 0)