141 lines
5.2 KiB
Python
141 lines
5.2 KiB
Python
import torch
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import torch.nn as nn
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from torch.nn.utils import weight_norm
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from typing import List, Optional, Tuple
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from einops import rearrange
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from torchaudio.transforms import Spectrogram
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class MultipleDiscriminator(nn.Module):
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def __init__(
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self, mpd: nn.Module, mrd: nn.Module
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):
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super().__init__()
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self.mpd = mpd
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self.mrd = mrd
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def forward(self, y: torch.Tensor, y_hat: torch.Tensor):
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y_d_rs, y_d_gs, fmap_rs, fmap_gs = [], [], [], []
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this_y_d_rs, this_y_d_gs, this_fmap_rs, this_fmap_gs = self.mpd(y.unsqueeze(dim=1), y_hat.unsqueeze(dim=1))
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y_d_rs += this_y_d_rs
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y_d_gs += this_y_d_gs
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fmap_rs += this_fmap_rs
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fmap_gs += this_fmap_gs
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this_y_d_rs, this_y_d_gs, this_fmap_rs, this_fmap_gs = self.mrd(y, y_hat)
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y_d_rs += this_y_d_rs
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y_d_gs += this_y_d_gs
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fmap_rs += this_fmap_rs
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fmap_gs += this_fmap_gs
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return y_d_rs, y_d_gs, fmap_rs, fmap_gs
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class MultiResolutionDiscriminator(nn.Module):
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def __init__(
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self,
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fft_sizes: Tuple[int, ...] = (2048, 1024, 512),
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num_embeddings: Optional[int] = None,
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):
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"""
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Multi-Resolution Discriminator module adapted from https://github.com/descriptinc/descript-audio-codec.
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Additionally, it allows incorporating conditional information with a learned embeddings table.
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Args:
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fft_sizes (tuple[int]): Tuple of window lengths for FFT. Defaults to (2048, 1024, 512).
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num_embeddings (int, optional): Number of embeddings. None means non-conditional discriminator.
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Defaults to None.
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"""
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super().__init__()
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self.discriminators = nn.ModuleList(
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[DiscriminatorR(window_length=w, num_embeddings=num_embeddings) for w in fft_sizes]
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)
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def forward(
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self, y: torch.Tensor, y_hat: torch.Tensor, bandwidth_id: torch.Tensor = None
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) -> Tuple[List[torch.Tensor], List[torch.Tensor], List[List[torch.Tensor]], List[List[torch.Tensor]]]:
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y_d_rs = []
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y_d_gs = []
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fmap_rs = []
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fmap_gs = []
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for d in self.discriminators:
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y_d_r, fmap_r = d(x=y, cond_embedding_id=bandwidth_id)
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y_d_g, fmap_g = d(x=y_hat, cond_embedding_id=bandwidth_id)
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y_d_rs.append(y_d_r)
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fmap_rs.append(fmap_r)
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y_d_gs.append(y_d_g)
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fmap_gs.append(fmap_g)
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return y_d_rs, y_d_gs, fmap_rs, fmap_gs
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class DiscriminatorR(nn.Module):
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def __init__(
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self,
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window_length: int,
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num_embeddings: Optional[int] = None,
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channels: int = 32,
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hop_factor: float = 0.25,
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bands: Tuple[Tuple[float, float], ...] = ((0.0, 0.1), (0.1, 0.25), (0.25, 0.5), (0.5, 0.75), (0.75, 1.0)),
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):
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super().__init__()
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self.window_length = window_length
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self.hop_factor = hop_factor
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self.spec_fn = Spectrogram(
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n_fft=window_length, hop_length=int(window_length * hop_factor), win_length=window_length, power=None
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)
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n_fft = window_length // 2 + 1
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bands = [(int(b[0] * n_fft), int(b[1] * n_fft)) for b in bands]
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self.bands = bands
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convs = lambda: nn.ModuleList(
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[
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weight_norm(nn.Conv2d(2, channels, (3, 9), (1, 1), padding=(1, 4))),
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weight_norm(nn.Conv2d(channels, channels, (3, 9), (1, 2), padding=(1, 4))),
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weight_norm(nn.Conv2d(channels, channels, (3, 9), (1, 2), padding=(1, 4))),
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weight_norm(nn.Conv2d(channels, channels, (3, 9), (1, 2), padding=(1, 4))),
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weight_norm(nn.Conv2d(channels, channels, (3, 3), (1, 1), padding=(1, 1))),
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]
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)
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self.band_convs = nn.ModuleList([convs() for _ in range(len(self.bands))])
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if num_embeddings is not None:
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self.emb = torch.nn.Embedding(num_embeddings=num_embeddings, embedding_dim=channels)
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torch.nn.init.zeros_(self.emb.weight)
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self.conv_post = weight_norm(nn.Conv2d(channels, 1, (3, 3), (1, 1), padding=(1, 1)))
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def spectrogram(self, x):
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# Remove DC offset
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x = x - x.mean(dim=-1, keepdims=True)
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# Peak normalize the volume of input audio
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x = 0.8 * x / (x.abs().max(dim=-1, keepdim=True)[0] + 1e-9)
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x = self.spec_fn(x)
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x = torch.view_as_real(x)
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x = rearrange(x, "b f t c -> b c t f")
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# Split into bands
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x_bands = [x[..., b[0]: b[1]] for b in self.bands]
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return x_bands
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def forward(self, x: torch.Tensor, cond_embedding_id: torch.Tensor = None):
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x_bands = self.spectrogram(x)
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fmap = []
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x = []
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for band, stack in zip(x_bands, self.band_convs):
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for i, layer in enumerate(stack):
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band = layer(band)
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band = torch.nn.functional.leaky_relu(band, 0.1)
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if i > 0:
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fmap.append(band)
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x.append(band)
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x = torch.cat(x, dim=-1)
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if cond_embedding_id is not None:
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emb = self.emb(cond_embedding_id)
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h = (emb.view(1, -1, 1, 1) * x).sum(dim=1, keepdims=True)
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else:
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h = 0
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x = self.conv_post(x)
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fmap.append(x)
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x += h
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return x, fmap
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