File size: 8,654 Bytes
a344f64
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200

import torch
import torch.nn as nn
from torch.nn import functional as nnf
from torch.utils.data import Dataset, DataLoader
from enum import Enum
from transformers import GPT2LMHeadModel
from typing import Tuple, Optional, Union

def get_clapcap(name: str):
    if name == "ClapCaption":
        return ClapCaptionModel
    else:
        raise Exception('The ClapCap model {} is incorrect or not supported'.format(name))

class MappingType(Enum):
    MLP = 'mlp'
    Transformer = 'transformer'

class MLP(nn.Module):
    def __init__(self, sizes: Tuple[int, ...], bias=True, act=nn.Tanh):
        super(MLP, self).__init__()
        layers = []
        for i in range(len(sizes) - 1):
            layers.append(nn.Linear(sizes[i], sizes[i + 1], bias=bias))
            if i < len(sizes) - 2:
                layers.append(act())
        self.model = nn.Sequential(*layers)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        return self.model(x)


class MlpTransformer(nn.Module):
    def __init__(self, in_dim, h_dim, out_d: Optional[int] = None, act=nnf.relu, dropout=0.):
        super().__init__()
        out_d = out_d if out_d is not None else in_dim
        self.fc1 = nn.Linear(in_dim, h_dim)
        self.act = act
        self.fc2 = nn.Linear(h_dim, out_d)
        self.dropout = nn.Dropout(dropout)

    def forward(self, x):
        x = self.fc1(x)
        x = self.act(x)
        x = self.dropout(x)
        x = self.fc2(x)
        x = self.dropout(x)
        return x

class MultiHeadAttention(nn.Module):

    def __init__(self, dim_self, dim_ref, num_heads, bias=True, dropout=0.):
        super().__init__()
        self.num_heads = num_heads
        head_dim = dim_self // num_heads
        self.scale = head_dim ** -0.5
        self.to_queries = nn.Linear(dim_self, dim_self, bias=bias)
        self.to_keys_values = nn.Linear(dim_ref, dim_self * 2, bias=bias)
        self.project = nn.Linear(dim_self, dim_self)
        self.dropout = nn.Dropout(dropout)

    def forward(self, x, y=None, mask=None):
        y = y if y is not None else x
        b, n, c = x.shape
        _, m, d = y.shape
        # b n h dh
        queries = self.to_queries(x).reshape(b, n, self.num_heads, c // self.num_heads)
        # b m 2 h dh
        keys_values = self.to_keys_values(y).reshape(b, m, 2, self.num_heads, c // self.num_heads)
        keys, values = keys_values[:, :, 0], keys_values[:, :, 1]
        attention = torch.einsum('bnhd,bmhd->bnmh', queries, keys) * self.scale
        if mask is not None:
            if mask.dim() == 2:
                mask = mask.unsqueeze(1)
            attention = attention.masked_fill(mask.unsqueeze(3), float("-inf"))
        attention = attention.softmax(dim=2)
        out = torch.einsum('bnmh,bmhd->bnhd', attention, values).reshape(b, n, c)
        out = self.project(out)
        return out, attention


class TransformerLayer(nn.Module):

    def forward_with_attention(self, x, y=None, mask=None):
        x_, attention = self.attn(self.norm1(x), y, mask)
        x = x + x_
        x = x + self.mlp(self.norm2(x))
        return x, attention

    def forward(self, x, y=None, mask=None):
        x = x + self.attn(self.norm1(x), y, mask)[0]
        x = x + self.mlp(self.norm2(x))
        return x

    def __init__(self, dim_self, dim_ref, num_heads, mlp_ratio=4., bias=False, dropout=0., act=nnf.relu,
                 norm_layer: nn.Module = nn.LayerNorm):
        super().__init__()
        self.norm1 = norm_layer(dim_self)
        self.attn = MultiHeadAttention(dim_self, dim_ref, num_heads, bias=bias, dropout=dropout)
        self.norm2 = norm_layer(dim_self)
        self.mlp = MlpTransformer(dim_self, int(dim_self * mlp_ratio), act=act, dropout=dropout)


class Transformer(nn.Module):
    def __init__(self, dim_self: int, num_heads: int, num_layers: int, dim_ref: Optional[int] = None,
                 mlp_ratio: float = 2., act=nnf.relu, norm_layer: nn.Module = nn.LayerNorm, enc_dec: bool = False):
        super(Transformer, self).__init__()
        dim_ref = dim_ref if dim_ref is not None else dim_self
        self.enc_dec = enc_dec
        if enc_dec:
            num_layers = num_layers * 2
        layers = []
        for i in range(num_layers):
            if i % 2 == 0 and enc_dec:  # cross
                layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
            elif enc_dec:  # self
                layers.append(TransformerLayer(dim_self, dim_self, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
            else:  # self or cross
                layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
        self.layers = nn.ModuleList(layers)

    def forward_with_attention(self, x, y=None, mask=None):
        attentions = []
        for layer in self.layers:
            x, att = layer.forward_with_attention(x, y, mask)
            attentions.append(att)
        return x, attentions

    def forward(self, x, y=None, mask=None):
        for i, layer in enumerate(self.layers):
            if i % 2 == 0 and self.enc_dec: # cross
                x = layer(x, y)
            elif self.enc_dec:  # self
                x = layer(x, x, mask)
            else:  # self or cross
                x = layer(x, y, mask)
        return x


class TransformerMapper(nn.Module):
    def __init__(self, dim_clip: int, dim_embedding: int, prefix_length: int, clip_length: int, num_layers: int = 8):
        super(TransformerMapper, self).__init__()
        self.clip_length = clip_length
        self.transformer = Transformer(dim_embedding, 8, num_layers)
        self.linear = nn.Linear(dim_clip, clip_length * dim_embedding)
        self.prefix_const = nn.Parameter(torch.randn(prefix_length, dim_embedding), requires_grad=True)

    def forward(self, x):
        x = self.linear(x).view(x.shape[0], self.clip_length, -1)
        prefix = self.prefix_const.unsqueeze(0).expand(x.shape[0], *self.prefix_const.shape)
        prefix = torch.cat((x, prefix), dim=1)
        out = self.transformer(prefix)[:, self.clip_length:]
        return out

class ClapCaptionModel(nn.Module):
    def __init__(self, clap, text_decoder: str, prefix_length: int, clip_length: Optional[int] = None, prefix_size: int = 512,
                 num_layers: int = 8, normalize_prefix: bool = True, mapping_type: str = None,\
                 freeze_audio_encoder_weights: bool = True, freeze_gpt_weights: bool = True):
        super(ClapCaptionModel, self).__init__()
        self.clap = clap.audio_encoder
        self.prefix_length = prefix_length
        self.normalize_prefix = normalize_prefix
        self.gpt = GPT2LMHeadModel.from_pretrained(text_decoder)
        self.gpt_embedding_size = self.gpt.transformer.wte.weight.shape[1]
        if mapping_type == 'mlp':
            self.clap_project = MLP((prefix_size, (self.gpt_embedding_size * prefix_length) // 2,
                                     self.gpt_embedding_size * prefix_length))
        else:
            self.clap_project = TransformerMapper(prefix_size, self.gpt_embedding_size, prefix_length,
                                                                     clip_length, num_layers)

        # Freeze all CLAP parameters
        if freeze_audio_encoder_weights:
            for p in self.clap.parameters():
                p.requires_grad = False
        
        if freeze_gpt_weights:
            for p in self.gpt.parameters():
                p.requires_grad = False

    def get_dummy_token(self, batch_size: int, device: torch.device) -> torch.Tensor:
        return torch.zeros(batch_size, self.prefix_length, dtype=torch.int64, device=device)

    def forward(self, audios: torch.Tensor, tokens: torch.Tensor, mask: Optional[torch.Tensor] = None,
                labels: Optional[torch.Tensor] = None):
        # get audio embeddings
        prefix, _ = self.clap(audios)
        # normalize prefix (audio embedding)
        if self.normalize_prefix:
            prefix = prefix / prefix.norm(2, -1).reshape(-1,1)

        embedding_text = self.gpt.transformer.wte(tokens['input_ids'])
        prefix_projections = self.clap_project(prefix).view(-1, self.prefix_length, self.gpt_embedding_size)
        embedding_cat = torch.cat((prefix_projections, embedding_text), dim=1)
        if labels is not None:
            dummy_token = self.get_dummy_token(tokens['input_ids'].shape[0], tokens['input_ids'].device)
            labels = torch.cat((dummy_token, tokens), dim=1)
        out = self.gpt(inputs_embeds=embedding_cat, labels=labels, attention_mask=mask)
        return out