1 files changed, 46 insertions, 0 deletions
diff --git a/become_yukarin/dataset/utility.py b/become_yukarin/dataset/utility.py
new file mode 100644
index 0000000..b2f5480
--- /dev/null
+++ b/become_yukarin/dataset/utility.py
@@ -0,0 +1,46 @@
+import fastdtw
+import nnmnkwii.metrics
+import numpy
+import scipy.interpolate
+
+
+class DTWAligner(object):
+    """
+    from https://github.com/r9y9/nnmnkwii/blob/4cade86b5c35b4e35615a2a8162ddc638018af0e/nnmnkwii/preprocessing/alignment.py#L14
+    """
+
+    def __init__(self, x, y, dist=lambda x, y: numpy.linalg.norm(x - y), radius=1):
+        assert x.ndim == 2 and y.ndim == 2
+
+        _, path = fastdtw.fastdtw(x, y, radius=radius, dist=dist)
+        self.normed_path_x = numpy.array(list(map(lambda l: l[0], path))) / len(x)
+        self.normed_path_y = numpy.array(list(map(lambda l: l[1], path))) / len(y)
+
+    def align_x(self, x):
+        path = self._interp_path(self.normed_path_x, len(x))
+        return x[path]
+
+    def align_y(self, y):
+        path = self._interp_path(self.normed_path_y, len(y))
+        return y[path]
+
+    def align(self, x, y):
+        return self.align_x(x), self.align_y(y)
+
+    @staticmethod
+    def align_and_transform(x, y, *args, **kwargs):
+        aligner = DTWAligner(*args, x=x, y=y, **kwargs)
+        return aligner.align(x, y)
+
+    @staticmethod
+    def _interp_path(normed_path: numpy.ndarray, target_length: int):
+        base = numpy.linspace(0, 1, len(normed_path))
+        target = numpy.linspace(0, 1, target_length)
+        path = scipy.interpolate.interp1d(base, normed_path)(target)
+        path = numpy.floor(path * target_length).astype(numpy.int)
+        return path
+
+
+class MFCCAligner(DTWAligner):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, dist=nnmnkwii.metrics.melcd, **kwargs)