diff --git a/deepspeech/modules/conv.py b/deepspeech/modules/conv.py
deleted file mode 100644
index 22a168800be17885c772f69d1ad3fd710f0abfe6..0000000000000000000000000000000000000000
--- a/deepspeech/modules/conv.py
+++ /dev/null
@@ -1,170 +0,0 @@
-# Copyright (c) 2021 PaddlePaddle Authors. 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.
-from paddle import nn
-from paddle.nn import functional as F
-
-from deepspeech.modules.activation import brelu
-from deepspeech.modules.mask import make_non_pad_mask
-from deepspeech.utils.log import Log
-
-logger = Log(__name__).getlog()
-
-__all__ = ['ConvStack', "conv_output_size"]
-
-
-def conv_output_size(I, F, P, S):
-    # https://stanford.edu/~shervine/teaching/cs-230/cheatsheet-convolutional-neural-networks#hyperparameters
-    # Output size after Conv:
-    #   By noting I the length of the input volume size, 
-    #   F the length of the filter, 
-    #   P the amount of zero padding, 
-    #   S the stride,
-    #   then the output size O of the feature map along that dimension is given by:
-    #       O = (I - F + Pstart + Pend) // S + 1
-    #   When Pstart == Pend == P, we can replace Pstart + Pend by 2P.
-    #   When Pstart == Pend == 0
-    #       O = (I - F - S) // S
-    # https://iq.opengenus.org/output-size-of-convolution/
-    # Output height = (Input height + padding height top + padding height bottom - kernel height) / (stride height) + 1
-    # Output width = (Output width + padding width right + padding width left - kernel width) / (stride width) + 1
-    return (I - F + 2 * P - S) // S
-
-
-# receptive field calculator
-# https://fomoro.com/research/article/receptive-field-calculator
-# https://stanford.edu/~shervine/teaching/cs-230/cheatsheet-convolutional-neural-networks#hyperparameters
-# https://distill.pub/2019/computing-receptive-fields/
-# Rl-1 = Sl * Rl + (Kl - Sl) 
-
-
-class ConvBn(nn.Layer):
-    """Convolution layer with batch normalization.
-
-    :param kernel_size: The x dimension of a filter kernel. Or input a tuple for
-                        two image dimension.
-    :type kernel_size: int|tuple|list
-    :param num_channels_in: Number of input channels.
-    :type num_channels_in: int
-    :param num_channels_out: Number of output channels.
-    :type num_channels_out: int
-    :param stride: The x dimension of the stride. Or input a tuple for two 
-                image dimension. 
-    :type stride: int|tuple|list
-    :param padding: The x dimension of the padding. Or input a tuple for two
-                    image dimension.
-    :type padding: int|tuple|list
-    :param act: Activation type, relu|brelu
-    :type act: string
-    :return: Batch norm layer after convolution layer.
-    :rtype: Variable
-
-    """
-
-    def __init__(self, num_channels_in, num_channels_out, kernel_size, stride,
-                 padding, act):
-
-        super().__init__()
-        assert len(kernel_size) == 2
-        assert len(stride) == 2
-        assert len(padding) == 2
-        self.kernel_size = kernel_size
-        self.stride = stride
-        self.padding = padding
-
-        self.conv = nn.Conv2D(
-            num_channels_in,
-            num_channels_out,
-            kernel_size=kernel_size,
-            stride=stride,
-            padding=padding,
-            weight_attr=None,
-            bias_attr=False,
-            data_format='NCHW')
-
-        self.bn = nn.BatchNorm2D(
-            num_channels_out,
-            weight_attr=None,
-            bias_attr=None,
-            data_format='NCHW')
-        self.act = F.relu if act == 'relu' else brelu
-
-    def forward(self, x, x_len):
-        """
-        x(Tensor): audio, shape [B, C, D, T]
-        """
-        x = self.conv(x)
-        x = self.bn(x)
-        x = self.act(x)
-
-        x_len = (x_len - self.kernel_size[1] + 2 * self.padding[1]
-                 ) // self.stride[1] + 1
-
-        # reset padding part to 0
-        masks = make_non_pad_mask(x_len)  #[B, T]
-        masks = masks.unsqueeze(1).unsqueeze(1)  # [B, 1, 1, T]
-        # https://github.com/PaddlePaddle/Paddle/pull/29265
-        # rhs will type promote to lhs
-        x = x * masks
-        return x, x_len
-
-
-class ConvStack(nn.Layer):
-    """Convolution group with stacked convolution layers.
-
-    :param feat_size: audio feature dim.
-    :type feat_size: int
-    :param num_stacks: Number of stacked convolution layers.
-    :type num_stacks: int
-    """
-
-    def __init__(self, feat_size, num_stacks):
-        super().__init__()
-        self.feat_size = feat_size  # D
-        self.num_stacks = num_stacks
-
-        self.conv_in = ConvBn(
-            num_channels_in=1,
-            num_channels_out=32,
-            kernel_size=(41, 11),  #[D, T]
-            stride=(2, 3),
-            padding=(20, 5),
-            act='brelu')
-
-        out_channel = 32
-        convs = [
-            ConvBn(
-                num_channels_in=32,
-                num_channels_out=out_channel,
-                kernel_size=(21, 11),
-                stride=(2, 1),
-                padding=(10, 5),
-                act='brelu') for i in range(num_stacks - 1)
-        ]
-        self.conv_stack = nn.LayerList(convs)
-
-        # conv output feat_dim
-        output_height = (feat_size - 1) // 2 + 1
-        for i in range(self.num_stacks - 1):
-            output_height = (output_height - 1) // 2 + 1
-        self.output_height = out_channel * output_height
-
-    def forward(self, x, x_len):
-        """
-        x: shape [B, C, D, T]
-        x_len : shape [B]
-        """
-        x, x_len = self.conv_in(x, x_len)
-        for i, conv in enumerate(self.conv_stack):
-            x, x_len = conv(x, x_len)
-        return x, x_len
diff --git a/deepspeech/modules/rnn.py b/deepspeech/modules/rnn.py
deleted file mode 100644
index 8f8b2a18dd5455943d03e9634f958b14caa3fc57..0000000000000000000000000000000000000000
--- a/deepspeech/modules/rnn.py
+++ /dev/null
@@ -1,314 +0,0 @@
-# Copyright (c) 2021 PaddlePaddle Authors. 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.
-import math
-
-import paddle
-from paddle import nn
-from paddle.nn import functional as F
-from paddle.nn import initializer as I
-
-from deepspeech.modules.activation import brelu
-from deepspeech.modules.mask import make_non_pad_mask
-from deepspeech.utils.log import Log
-
-logger = Log(__name__).getlog()
-
-__all__ = ['RNNStack']
-
-
-class RNNCell(nn.RNNCellBase):
-    r"""
-    Elman RNN (SimpleRNN) cell. Given the inputs and previous states, it 
-    computes the outputs and updates states.
-    The formula used is as follows:
-    .. math::
-        h_{t} & = act(x_{t} + b_{ih} + W_{hh}h_{t-1} + b_{hh})
-        y_{t} & = h_{t}
-    
-    where :math:`act` is for :attr:`activation`.
-    """
-
-    def __init__(self,
-                 hidden_size: int,
-                 activation="tanh",
-                 weight_ih_attr=None,
-                 weight_hh_attr=None,
-                 bias_ih_attr=None,
-                 bias_hh_attr=None,
-                 name=None):
-        super().__init__()
-        std = 1.0 / math.sqrt(hidden_size)
-        self.weight_hh = self.create_parameter(
-            (hidden_size, hidden_size),
-            weight_hh_attr,
-            default_initializer=I.Uniform(-std, std))
-        self.bias_ih = None
-        self.bias_hh = self.create_parameter(
-            (hidden_size, ),
-            bias_hh_attr,
-            is_bias=True,
-            default_initializer=I.Uniform(-std, std))
-
-        self.hidden_size = hidden_size
-        if activation not in ["tanh", "relu", "brelu"]:
-            raise ValueError(
-                "activation for SimpleRNNCell should be tanh or relu, "
-                "but get {}".format(activation))
-        self.activation = activation
-        self._activation_fn = paddle.tanh \
-            if activation == "tanh" \
-            else F.relu
-        if activation == 'brelu':
-            self._activation_fn = brelu
-
-    def forward(self, inputs, states=None):
-        if states is None:
-            states = self.get_initial_states(inputs, self.state_shape)
-        pre_h = states
-        i2h = inputs
-        if self.bias_ih is not None:
-            i2h += self.bias_ih
-        h2h = paddle.matmul(pre_h, self.weight_hh, transpose_y=True)
-        if self.bias_hh is not None:
-            h2h += self.bias_hh
-        h = self._activation_fn(i2h + h2h)
-        return h, h
-
-    @property
-    def state_shape(self):
-        return (self.hidden_size, )
-
-
-class GRUCell(nn.RNNCellBase):
-    r"""
-    Gated Recurrent Unit (GRU) RNN cell. Given the inputs and previous states, 
-    it computes the outputs and updates states.
-    The formula for GRU used is as follows:
-    ..  math::
-        r_{t} & = \sigma(W_{ir}x_{t} + b_{ir} + W_{hr}h_{t-1} + b_{hr})
-        z_{t} & = \sigma(W_{iz}x_{t} + b_{iz} + W_{hz}h_{t-1} + b_{hz})
-        \widetilde{h}_{t} & = \tanh(W_{ic}x_{t} + b_{ic} + r_{t} * (W_{hc}h_{t-1} + b_{hc}))
-        h_{t} & = z_{t} * h_{t-1} + (1 - z_{t}) * \widetilde{h}_{t}
-        y_{t} & = h_{t}
-    
-    where :math:`\sigma` is the sigmoid fucntion, and * is the elemetwise 
-    multiplication operator.
-    """
-
-    def __init__(self,
-                 input_size: int,
-                 hidden_size: int,
-                 weight_ih_attr=None,
-                 weight_hh_attr=None,
-                 bias_ih_attr=None,
-                 bias_hh_attr=None,
-                 name=None):
-        super().__init__()
-        std = 1.0 / math.sqrt(hidden_size)
-        self.weight_hh = self.create_parameter(
-            (3 * hidden_size, hidden_size),
-            weight_hh_attr,
-            default_initializer=I.Uniform(-std, std))
-        self.bias_ih = None
-        self.bias_hh = self.create_parameter(
-            (3 * hidden_size, ),
-            bias_hh_attr,
-            is_bias=True,
-            default_initializer=I.Uniform(-std, std))
-
-        self.hidden_size = hidden_size
-        self.input_size = input_size
-        self._gate_activation = F.sigmoid
-        self._activation = paddle.tanh
-
-    def forward(self, inputs, states=None):
-        if states is None:
-            states = self.get_initial_states(inputs, self.state_shape)
-
-        pre_hidden = states
-        x_gates = inputs
-        if self.bias_ih is not None:
-            x_gates = x_gates + self.bias_ih
-        h_gates = paddle.matmul(pre_hidden, self.weight_hh, transpose_y=True)
-        if self.bias_hh is not None:
-            h_gates = h_gates + self.bias_hh
-
-        x_r, x_z, x_c = paddle.split(x_gates, num_or_sections=3, axis=1)
-        h_r, h_z, h_c = paddle.split(h_gates, num_or_sections=3, axis=1)
-
-        r = self._gate_activation(x_r + h_r)
-        z = self._gate_activation(x_z + h_z)
-        c = self._activation(x_c + r * h_c)  # apply reset gate after mm
-        h = (pre_hidden - c) * z + c
-        # https://www.paddlepaddle.org.cn/documentation/docs/zh/api/paddle/fluid/layers/dynamic_gru_cn.html#dynamic-gru
-
-        return h, h
-
-    @property
-    def state_shape(self):
-        r"""
-        The `state_shape` of GRUCell is a shape `[hidden_size]` (-1 for batch
-        size would be automatically inserted into shape). The shape corresponds
-        to the shape of :math:`h_{t-1}`.
-        """
-        return (self.hidden_size, )
-
-
-class BiRNNWithBN(nn.Layer):
-    """Bidirectonal simple rnn layer with sequence-wise batch normalization.
-    The batch normalization is only performed on input-state weights.
-
-    :param size: Dimension of RNN cells.
-    :type size: int
-    :param share_weights: Whether to share input-hidden weights between
-                          forward and backward directional RNNs.
-    :type share_weights: bool
-    :return: Bidirectional simple rnn layer.
-    :rtype: Variable
-    """
-
-    def __init__(self, i_size: int, h_size: int, share_weights: bool):
-        super().__init__()
-        self.share_weights = share_weights
-        if self.share_weights:
-            #input-hidden weights shared between bi-directional rnn.
-            self.fw_fc = nn.Linear(i_size, h_size, bias_attr=False)
-            # batch norm is only performed on input-state projection
-            self.fw_bn = nn.BatchNorm1D(
-                h_size, bias_attr=None, data_format='NLC')
-            self.bw_fc = self.fw_fc
-            self.bw_bn = self.fw_bn
-        else:
-            self.fw_fc = nn.Linear(i_size, h_size, bias_attr=False)
-            self.fw_bn = nn.BatchNorm1D(
-                h_size, bias_attr=None, data_format='NLC')
-            self.bw_fc = nn.Linear(i_size, h_size, bias_attr=False)
-            self.bw_bn = nn.BatchNorm1D(
-                h_size, bias_attr=None, data_format='NLC')
-
-        self.fw_cell = RNNCell(hidden_size=h_size, activation='brelu')
-        self.bw_cell = RNNCell(hidden_size=h_size, activation='brelu')
-        self.fw_rnn = nn.RNN(
-            self.fw_cell, is_reverse=False, time_major=False)  #[B, T, D]
-        self.bw_rnn = nn.RNN(
-            self.fw_cell, is_reverse=True, time_major=False)  #[B, T, D]
-
-    def forward(self, x: paddle.Tensor, x_len: paddle.Tensor):
-        # x, shape [B, T, D]
-        fw_x = self.fw_bn(self.fw_fc(x))
-        bw_x = self.bw_bn(self.bw_fc(x))
-        fw_x, _ = self.fw_rnn(inputs=fw_x, sequence_length=x_len)
-        bw_x, _ = self.bw_rnn(inputs=bw_x, sequence_length=x_len)
-        x = paddle.concat([fw_x, bw_x], axis=-1)
-        return x, x_len
-
-
-class BiGRUWithBN(nn.Layer):
-    """Bidirectonal gru layer with sequence-wise batch normalization.
-    The batch normalization is only performed on input-state weights.
-
-    :param name: Name of the layer.
-    :type name: string
-    :param input: Input layer.
-    :type input: Variable
-    :param size: Dimension of GRU cells.
-    :type size: int
-    :param act: Activation type.
-    :type act: string
-    :return: Bidirectional GRU layer.
-    :rtype: Variable
-    """
-
-    def __init__(self, i_size: int, h_size: int):
-        super().__init__()
-        hidden_size = h_size * 3
-
-        self.fw_fc = nn.Linear(i_size, hidden_size, bias_attr=False)
-        self.fw_bn = nn.BatchNorm1D(
-            hidden_size, bias_attr=None, data_format='NLC')
-        self.bw_fc = nn.Linear(i_size, hidden_size, bias_attr=False)
-        self.bw_bn = nn.BatchNorm1D(
-            hidden_size, bias_attr=None, data_format='NLC')
-
-        self.fw_cell = GRUCell(input_size=hidden_size, hidden_size=h_size)
-        self.bw_cell = GRUCell(input_size=hidden_size, hidden_size=h_size)
-        self.fw_rnn = nn.RNN(
-            self.fw_cell, is_reverse=False, time_major=False)  #[B, T, D]
-        self.bw_rnn = nn.RNN(
-            self.fw_cell, is_reverse=True, time_major=False)  #[B, T, D]
-
-    def forward(self, x, x_len):
-        # x, shape [B, T, D]
-        fw_x = self.fw_bn(self.fw_fc(x))
-        bw_x = self.bw_bn(self.bw_fc(x))
-        fw_x, _ = self.fw_rnn(inputs=fw_x, sequence_length=x_len)
-        bw_x, _ = self.bw_rnn(inputs=bw_x, sequence_length=x_len)
-        x = paddle.concat([fw_x, bw_x], axis=-1)
-        return x, x_len
-
-
-class RNNStack(nn.Layer):
-    """RNN group with stacked bidirectional simple RNN or GRU layers.
-
-    :param input: Input layer.
-    :type input: Variable
-    :param size: Dimension of RNN cells in each layer.
-    :type size: int
-    :param num_stacks: Number of stacked rnn layers.
-    :type num_stacks: int
-    :param use_gru: Use gru if set True. Use simple rnn if set False.
-    :type use_gru: bool
-    :param share_rnn_weights: Whether to share input-hidden weights between
-                              forward and backward directional RNNs.
-                              It is only available when use_gru=False.
-    :type share_weights: bool
-    :return: Output layer of the RNN group.
-    :rtype: Variable
-    """
-
-    def __init__(self,
-                 i_size: int,
-                 h_size: int,
-                 num_stacks: int,
-                 use_gru: bool,
-                 share_rnn_weights: bool):
-        super().__init__()
-        rnn_stacks = []
-        for i in range(num_stacks):
-            if use_gru:
-                #default:GRU using tanh
-                rnn_stacks.append(BiGRUWithBN(i_size=i_size, h_size=h_size))
-            else:
-                rnn_stacks.append(
-                    BiRNNWithBN(
-                        i_size=i_size,
-                        h_size=h_size,
-                        share_weights=share_rnn_weights))
-            i_size = h_size * 2
-
-        self.rnn_stacks = nn.LayerList(rnn_stacks)
-
-    def forward(self, x: paddle.Tensor, x_len: paddle.Tensor):
-        """
-        x: shape [B, T, D]
-        x_len: shpae [B]
-        """
-        for i, rnn in enumerate(self.rnn_stacks):
-            x, x_len = rnn(x, x_len)
-            masks = make_non_pad_mask(x_len)  #[B, T]
-            masks = masks.unsqueeze(-1)  # [B, T, 1]
-            # https://github.com/PaddlePaddle/Paddle/pull/29265
-            # rhs will type promote to lhs
-            x = x * masks
-        return x, x_len