def __init__(self, mix_scp, s1_scp, s2_scp):
        """Initialize DataReader. (2 mixtures)

        Args:
            mix_scp: scp file for mixed waves (KALDI format)
        """
        check(mix_scp, s1_scp, s2_scp)
        self.key = read_key(mix_scp)
        self.mix_path = read_path(mix_scp)
        self.s1_path = read_path(s1_scp)
        self.s2_path = read_path(s2_scp)
    def __init__(self,
                 mix_c1_scp,
                 s1_c1_scp,
                 s2_c1_scp,
                 mix_c2_scp,
                 s1_c2_scp,
                 s2_c2_scp,
                 sample_rate,
                 sample_clip_size=4):
        """Initialize the TimeDomainDateset. (2 mixtures)

        Args:
            mix_scp: scp file for mixed waves (KALDI format)
            s1_scp: scp file for speaker 1
            s2_scp: scp file for speaker 2
            sample_clip_size: segmental length (default: 4s)
        """
        check(mix_c1_scp, s1_c1_scp, s2_c1_scp, mix_c2_scp, s1_c2_scp,
              s2_c2_scp)
        self.sample_rate = sample_rate
        self.sample_clip_size = sample_clip_size
        self.segment_length = self.sample_rate * self.sample_clip_size

        self.mix_c1_path = read_path(mix_c1_scp)
        self.s1_c1_path = read_path(s1_c1_scp)
        self.s2_c1_path = read_path(s2_c1_scp)
        self.mix_c2_path = read_path(mix_c2_scp)
        self.s1_c2_path = read_path(s1_c2_scp)
        self.s2_c2_path = read_path(s2_c2_scp)

        self.retrieve_index = []
        for i in range(len(self.mix_c1_path)):
            sample_size = len(wavread(self.mix_c1_path[i])[0])
            if sample_size < self.segment_length:
                # wave length is smaller than segmental length
                if sample_size * 2 < self.segment_length:
                    continue
                self.retrieve_index.append((i, -1))
            else:
                # Cut wave into clips and restore the retrieve index
                sample_index = 0
                while sample_index + self.segment_length < sample_size:
                    self.retrieve_index.append((i, sample_index))
                    sample_index += self.segment_length
                if sample_index != sample_size - 1:
                    self.retrieve_index.append(
                        (i, sample_size - self.segment_length))