# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2019 Mobvoi Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# Modified from wenet(https://github.com/wenet-e2e/wenet)
import paddle
from paddle import nn
from paddlespeech.s2t.utils.log import Log
logger = Log(__name__).getlog()
__all__ = ['GlobalCMVN']
[docs]class GlobalCMVN(nn.Layer):
def __init__(self,
mean: paddle.Tensor,
istd: paddle.Tensor,
norm_var: bool=True):
"""
Args:
mean (paddle.Tensor): mean stats
istd (paddle.Tensor): inverse std, std which is 1.0 / std
"""
super().__init__()
assert mean.shape == istd.shape
self.norm_var = norm_var
# The buffer can be accessed from this module using self.mean
self.register_buffer("mean", mean)
self.register_buffer("istd", istd)
def __repr__(self):
return ("{name}(mean={mean}, istd={istd}, norm_var={norm_var})".format(
name=self.__class__.__name__,
mean=self.mean,
istd=self.istd,
norm_var=self.norm_var))
[docs] def forward(self, x: paddle.Tensor):
"""
Args:
x (paddle.Tensor): (batch, max_len, feat_dim)
Returns:
(paddle.Tensor): normalized feature
"""
x = x - self.mean
if self.norm_var:
x = x * self.istd
return x