File size: 4,910 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
# 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.

import torch
import torch.nn.functional as F
import torch.nn as nn
from torch.nn.utils import weight_norm, remove_weight_norm, spectral_norm
from torch import nn

LRELU_SLOPE = 0.1


# This code is a refined MRD adopted from BigVGAN under the MIT License
# https://github.com/NVIDIA/BigVGAN


class DiscriminatorR(nn.Module):
    def __init__(self, cfg, resolution):
        super().__init__()

        self.resolution = resolution
        assert (
            len(self.resolution) == 3
        ), "MRD layer requires list with len=3, got {}".format(self.resolution)
        self.lrelu_slope = LRELU_SLOPE

        norm_f = (
            weight_norm if cfg.model.mrd.use_spectral_norm == False else spectral_norm
        )
        if cfg.model.mrd.mrd_override:
            print(
                "INFO: overriding MRD use_spectral_norm as {}".format(
                    cfg.model.mrd.mrd_use_spectral_norm
                )
            )
            norm_f = (
                weight_norm
                if cfg.model.mrd.mrd_use_spectral_norm == False
                else spectral_norm
            )
        self.d_mult = cfg.model.mrd.discriminator_channel_mult_factor
        if cfg.model.mrd.mrd_override:
            print(
                "INFO: overriding mrd channel multiplier as {}".format(
                    cfg.model.mrd.mrd_channel_mult
                )
            )
            self.d_mult = cfg.model.mrd.mrd_channel_mult

        self.convs = nn.ModuleList(
            [
                norm_f(nn.Conv2d(1, int(32 * self.d_mult), (3, 9), padding=(1, 4))),
                norm_f(
                    nn.Conv2d(
                        int(32 * self.d_mult),
                        int(32 * self.d_mult),
                        (3, 9),
                        stride=(1, 2),
                        padding=(1, 4),
                    )
                ),
                norm_f(
                    nn.Conv2d(
                        int(32 * self.d_mult),
                        int(32 * self.d_mult),
                        (3, 9),
                        stride=(1, 2),
                        padding=(1, 4),
                    )
                ),
                norm_f(
                    nn.Conv2d(
                        int(32 * self.d_mult),
                        int(32 * self.d_mult),
                        (3, 9),
                        stride=(1, 2),
                        padding=(1, 4),
                    )
                ),
                norm_f(
                    nn.Conv2d(
                        int(32 * self.d_mult),
                        int(32 * self.d_mult),
                        (3, 3),
                        padding=(1, 1),
                    )
                ),
            ]
        )
        self.conv_post = norm_f(
            nn.Conv2d(int(32 * self.d_mult), 1, (3, 3), padding=(1, 1))
        )

    def forward(self, x):
        fmap = []

        x = self.spectrogram(x)
        x = x.unsqueeze(1)
        for l in self.convs:
            x = l(x)
            x = F.leaky_relu(x, self.lrelu_slope)
            fmap.append(x)
        x = self.conv_post(x)
        fmap.append(x)
        x = torch.flatten(x, 1, -1)

        return x, fmap

    def spectrogram(self, x):
        n_fft, hop_length, win_length = self.resolution
        x = F.pad(
            x,
            (int((n_fft - hop_length) / 2), int((n_fft - hop_length) / 2)),
            mode="reflect",
        )
        x = x.squeeze(1)
        x = torch.stft(
            x,
            n_fft=n_fft,
            hop_length=hop_length,
            win_length=win_length,
            center=False,
            return_complex=True,
        )
        x = torch.view_as_real(x)  # [B, F, TT, 2]
        mag = torch.norm(x, p=2, dim=-1)  # [B, F, TT]

        return mag


class MultiResolutionDiscriminator(nn.Module):
    def __init__(self, cfg, debug=False):
        super().__init__()
        self.resolutions = cfg.model.mrd.resolutions
        assert (
            len(self.resolutions) == 3
        ), "MRD requires list of list with len=3, each element having a list with len=3. got {}".format(
            self.resolutions
        )
        self.discriminators = nn.ModuleList(
            [DiscriminatorR(cfg, resolution) for resolution in self.resolutions]
        )

    def forward(self, y, y_hat):
        y_d_rs = []
        y_d_gs = []
        fmap_rs = []
        fmap_gs = []

        for i, d in enumerate(self.discriminators):
            y_d_r, fmap_r = d(x=y)
            y_d_g, fmap_g = d(x=y_hat)
            y_d_rs.append(y_d_r)
            fmap_rs.append(fmap_r)
            y_d_gs.append(y_d_g)
            fmap_gs.append(fmap_g)

        return y_d_rs, y_d_gs, fmap_rs, fmap_gs