File size: 5,799 Bytes
c968fc3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
# Copyright (c) 2023 Amphion.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

# This model code is adopted from DiffWave/model.py under the Apache License
# https://github.com/lmnt-com/diffwave
# Only the config-related varaible names are changed.

import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F

from math import sqrt


Linear = nn.Linear
ConvTranspose2d = nn.ConvTranspose2d


def Conv1d(*args, **kwargs):
    layer = nn.Conv1d(*args, **kwargs)
    nn.init.kaiming_normal_(layer.weight)
    return layer


@torch.jit.script
def silu(x):
    return x * torch.sigmoid(x)


class DiffusionEmbedding(nn.Module):
    def __init__(self, max_steps):
        super().__init__()
        self.register_buffer(
            "embedding", self._build_embedding(max_steps), persistent=False
        )
        self.projection1 = Linear(128, 512)
        self.projection2 = Linear(512, 512)

    def forward(self, diffusion_step):
        if diffusion_step.dtype in [torch.int32, torch.int64]:
            x = self.embedding[diffusion_step]
        else:
            x = self._lerp_embedding(diffusion_step)
        x = self.projection1(x)
        x = silu(x)
        x = self.projection2(x)
        x = silu(x)
        return x

    def _lerp_embedding(self, t):
        low_idx = torch.floor(t).long()
        high_idx = torch.ceil(t).long()
        low = self.embedding[low_idx]
        high = self.embedding[high_idx]
        return low + (high - low) * (t - low_idx)

    def _build_embedding(self, max_steps):
        steps = torch.arange(max_steps).unsqueeze(1)  # [T,1]
        dims = torch.arange(64).unsqueeze(0)  # [1,64]
        table = steps * 10.0 ** (dims * 4.0 / 63.0)  # [T,64]
        table = torch.cat([torch.sin(table), torch.cos(table)], dim=1)
        return table


class SpectrogramUpsampler(nn.Module):
    def __init__(self, upsample_factors):
        super().__init__()
        self.conv1 = ConvTranspose2d(
            1,
            1,
            [3, upsample_factors[0] * 2],
            stride=[1, upsample_factors[0]],
            padding=[1, upsample_factors[0] // 2],
        )
        self.conv2 = ConvTranspose2d(
            1,
            1,
            [3, upsample_factors[1] * 2],
            stride=[1, upsample_factors[1]],
            padding=[1, upsample_factors[1] // 2],
        )

    def forward(self, x):
        x = torch.unsqueeze(x, 1)
        x = self.conv1(x)
        x = F.leaky_relu(x, 0.4)
        x = self.conv2(x)
        x = F.leaky_relu(x, 0.4)
        x = torch.squeeze(x, 1)
        return x


class ResidualBlock(nn.Module):
    def __init__(self, n_mels, residual_channels, dilation):
        super().__init__()
        self.dilated_conv = Conv1d(
            residual_channels,
            2 * residual_channels,
            3,
            padding=dilation,
            dilation=dilation,
        )
        self.diffusion_projection = Linear(512, residual_channels)

        self.conditioner_projection = Conv1d(n_mels, 2 * residual_channels, 1)

        self.output_projection = Conv1d(residual_channels, 2 * residual_channels, 1)

    def forward(self, x, diffusion_step, conditioner):
        diffusion_step = self.diffusion_projection(diffusion_step).unsqueeze(-1)
        y = x + diffusion_step

        conditioner = self.conditioner_projection(conditioner)
        y = self.dilated_conv(y) + conditioner

        gate, filter = torch.chunk(y, 2, dim=1)
        y = torch.sigmoid(gate) * torch.tanh(filter)

        y = self.output_projection(y)
        residual, skip = torch.chunk(y, 2, dim=1)
        return (x + residual) / sqrt(2.0), skip


class DiffWave(nn.Module):
    def __init__(self, cfg):
        super().__init__()
        self.cfg = cfg
        self.cfg.model.diffwave.noise_schedule = np.linspace(
            self.cfg.model.diffwave.noise_schedule_factors[0],
            self.cfg.model.diffwave.noise_schedule_factors[1],
            self.cfg.model.diffwave.noise_schedule_factors[2],
        ).tolist()
        self.input_projection = Conv1d(1, self.cfg.model.diffwave.residual_channels, 1)
        self.diffusion_embedding = DiffusionEmbedding(
            len(self.cfg.model.diffwave.noise_schedule)
        )
        self.spectrogram_upsampler = SpectrogramUpsampler(
            self.cfg.model.diffwave.upsample_factors
        )

        self.residual_layers = nn.ModuleList(
            [
                ResidualBlock(
                    self.cfg.preprocess.n_mel,
                    self.cfg.model.diffwave.residual_channels,
                    2 ** (i % self.cfg.model.diffwave.dilation_cycle_length),
                )
                for i in range(self.cfg.model.diffwave.residual_layers)
            ]
        )
        self.skip_projection = Conv1d(
            self.cfg.model.diffwave.residual_channels,
            self.cfg.model.diffwave.residual_channels,
            1,
        )
        self.output_projection = Conv1d(self.cfg.model.diffwave.residual_channels, 1, 1)
        nn.init.zeros_(self.output_projection.weight)

    def forward(self, audio, diffusion_step, spectrogram):
        x = audio.unsqueeze(1)
        x = self.input_projection(x)
        x = F.relu(x)

        diffusion_step = self.diffusion_embedding(diffusion_step)
        spectrogram = self.spectrogram_upsampler(spectrogram)

        skip = None
        for layer in self.residual_layers:
            x, skip_connection = layer(x, diffusion_step, spectrogram)
            skip = skip_connection if skip is None else skip_connection + skip

        x = skip / sqrt(len(self.residual_layers))
        x = self.skip_projection(x)
        x = F.relu(x)
        x = self.output_projection(x)
        return x