# Copyright (c) Alibaba, Inc. and its affiliates.
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# Part of the implementation is borrowed from espnet/espnet.
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from typing import Tuple
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import numpy as np
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import torch
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import torchaudio.compliance.kaldi as kaldi
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from funasr.models.frontend.abs_frontend import AbsFrontend
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from typeguard import check_argument_types
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from torch.nn.utils.rnn import pad_sequence
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def load_cmvn(cmvn_file):
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with open(cmvn_file, 'r', encoding='utf-8') as f:
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lines = f.readlines()
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means_list = []
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vars_list = []
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for i in range(len(lines)):
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line_item = lines[i].split()
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if line_item[0] == '<AddShift>':
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line_item = lines[i + 1].split()
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if line_item[0] == '<LearnRateCoef>':
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add_shift_line = line_item[3:(len(line_item) - 1)]
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means_list = list(add_shift_line)
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continue
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elif line_item[0] == '<Rescale>':
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line_item = lines[i + 1].split()
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if line_item[0] == '<LearnRateCoef>':
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rescale_line = line_item[3:(len(line_item) - 1)]
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vars_list = list(rescale_line)
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continue
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means = np.array(means_list).astype(np.float)
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vars = np.array(vars_list).astype(np.float)
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cmvn = np.array([means, vars])
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cmvn = torch.as_tensor(cmvn)
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return cmvn
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def apply_cmvn(inputs, cmvn_file): # noqa
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"""
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Apply CMVN with mvn data
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"""
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device = inputs.device
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dtype = inputs.dtype
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frame, dim = inputs.shape
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cmvn = load_cmvn(cmvn_file)
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means = np.tile(cmvn[0:1, :dim], (frame, 1))
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vars = np.tile(cmvn[1:2, :dim], (frame, 1))
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inputs += torch.from_numpy(means).type(dtype).to(device)
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inputs *= torch.from_numpy(vars).type(dtype).to(device)
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return inputs.type(torch.float32)
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def apply_lfr(inputs, lfr_m, lfr_n):
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LFR_inputs = []
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T = inputs.shape[0]
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T_lfr = int(np.ceil(T / lfr_n))
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left_padding = inputs[0].repeat((lfr_m - 1) // 2, 1)
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inputs = torch.vstack((left_padding, inputs))
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T = T + (lfr_m - 1) // 2
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for i in range(T_lfr):
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if lfr_m <= T - i * lfr_n:
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LFR_inputs.append((inputs[i * lfr_n:i * lfr_n + lfr_m]).view(1, -1))
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else: # process last LFR frame
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num_padding = lfr_m - (T - i * lfr_n)
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frame = (inputs[i * lfr_n:]).view(-1)
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for _ in range(num_padding):
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frame = torch.hstack((frame, inputs[-1]))
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LFR_inputs.append(frame)
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LFR_outputs = torch.vstack(LFR_inputs)
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return LFR_outputs.type(torch.float32)
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class WavFrontend(AbsFrontend):
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"""Conventional frontend structure for ASR.
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"""
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def __init__(
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self,
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cmvn_file: str = None,
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fs: int = 16000,
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window: str = 'hamming',
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n_mels: int = 80,
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frame_length: int = 25,
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frame_shift: int = 10,
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filter_length_min: int = -1,
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filter_length_max: int = -1,
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lfr_m: int = 1,
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lfr_n: int = 1,
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dither: float = 1.0
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):
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assert check_argument_types()
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super().__init__()
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self.fs = fs
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self.window = window
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self.n_mels = n_mels
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self.frame_length = frame_length
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self.frame_shift = frame_shift
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self.filter_length_min = filter_length_min
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self.filter_length_max = filter_length_max
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self.lfr_m = lfr_m
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self.lfr_n = lfr_n
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self.cmvn_file = cmvn_file
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self.dither = dither
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def output_size(self) -> int:
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return self.n_mels * self.lfr_m
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def forward(
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self,
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input: torch.Tensor,
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input_lengths: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
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batch_size = input.size(0)
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feats = []
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feats_lens = []
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for i in range(batch_size):
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waveform_length = input_lengths[i]
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waveform = input[i][:waveform_length]
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waveform = waveform * (1 << 15)
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waveform = waveform.unsqueeze(0)
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mat = kaldi.fbank(waveform,
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num_mel_bins=self.n_mels,
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frame_length=self.frame_length,
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frame_shift=self.frame_shift,
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dither=self.dither,
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energy_floor=0.0,
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window_type=self.window,
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sample_frequency=self.fs)
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if self.lfr_m != 1 or self.lfr_n != 1:
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mat = apply_lfr(mat, self.lfr_m, self.lfr_n)
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if self.cmvn_file is not None:
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mat = apply_cmvn(mat, self.cmvn_file)
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feat_length = mat.size(0)
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feats.append(mat)
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feats_lens.append(feat_length)
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feats_lens = torch.as_tensor(feats_lens)
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feats_pad = pad_sequence(feats,
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batch_first=True,
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padding_value=0.0)
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return feats_pad, feats_lens
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def forward_fbank(
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self,
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input: torch.Tensor,
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input_lengths: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
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batch_size = input.size(0)
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feats = []
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feats_lens = []
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for i in range(batch_size):
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waveform_length = input_lengths[i]
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waveform = input[i][:waveform_length]
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waveform = waveform * (1 << 15)
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waveform = waveform.unsqueeze(0)
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mat = kaldi.fbank(waveform,
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num_mel_bins=self.n_mels,
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frame_length=self.frame_length,
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frame_shift=self.frame_shift,
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dither=self.dither,
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energy_floor=0.0,
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window_type=self.window,
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sample_frequency=self.fs)
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# if self.lfr_m != 1 or self.lfr_n != 1:
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# mat = apply_lfr(mat, self.lfr_m, self.lfr_n)
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# if self.cmvn_file is not None:
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# mat = apply_cmvn(mat, self.cmvn_file)
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feat_length = mat.size(0)
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feats.append(mat)
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feats_lens.append(feat_length)
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feats_lens = torch.as_tensor(feats_lens)
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feats_pad = pad_sequence(feats,
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batch_first=True,
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padding_value=0.0)
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return feats_pad, feats_lens
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def forward_lfr_cmvn(
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self,
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input: torch.Tensor,
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input_lengths: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
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batch_size = input.size(0)
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feats = []
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feats_lens = []
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for i in range(batch_size):
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mat = input[i, :input_lengths[i], :]
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if self.lfr_m != 1 or self.lfr_n != 1:
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mat = apply_lfr(mat, self.lfr_m, self.lfr_n)
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if self.cmvn_file is not None:
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mat = apply_cmvn(mat, self.cmvn_file)
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feat_length = mat.size(0)
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feats.append(mat)
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feats_lens.append(feat_length)
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feats_lens = torch.as_tensor(feats_lens)
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feats_pad = pad_sequence(feats,
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batch_first=True,
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padding_value=0.0)
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return feats_pad, feats_lens
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