    def valid_length(self, length):
        """
        Return the nearest valid length to use with the model so that
        there is no time steps left over in a convolutions, e.g. for all
        layers, size of the input - kernel_size % stride = 0.

        If the mixture has a valid length, the estimated sources
        will have exactly the same length.
        """
        length = math.ceil(length * self.resample)
        for _ in range(self.depth):
            length = math.ceil((length - self.kernel_size) / self.stride) + 1
            length = max(length, 1)
        for _ in range(self.depth):
            length = (length - 1) * self.stride + self.kernel_size
        length = int(math.ceil(length / self.resample))
        return int(length)
Return the nearest valid length to use with the model so that
there is no time steps left over in a convolutions, e.g. for all
layers, size of the input - kernel_size % stride = 0.

If the mixture has a valid length, the estimated sources
will have exactly the same length.
examples/speech_synthesis/preprocessing/denoiser/demucs.py