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# Copyright (c) 2024 Amphion.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
from typing import Union
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from einops import rearrange
from torch.nn.utils import weight_norm
from models.codec.amphion_codec.quantize.factorized_vector_quantize import (
FactorizedVectorQuantize,
)
from models.codec.amphion_codec.quantize.vector_quantize import VectorQuantize
from models.codec.amphion_codec.quantize.lookup_free_quantize import LookupFreeQuantize
class ResidualVQ(nn.Module):
"""
Introduced in SoundStream: An end2end neural audio codec
https://arxiv.org/abs/2107.03312
"""
def __init__(
self,
input_dim: int = 256,
num_quantizers: int = 8,
codebook_size: int = 1024,
codebook_dim: int = 256,
quantizer_type: str = "vq", # "vq" or "fvq" or "lfq"
quantizer_dropout: float = 0.5,
**kwargs,
):
super().__init__()
self.input_dim = input_dim
self.num_quantizers = num_quantizers
self.codebook_size = codebook_size
self.codebook_dim = codebook_dim
self.quantizer_type = quantizer_type
self.quantizer_dropout = quantizer_dropout
if quantizer_type == "vq":
VQ = VectorQuantize
elif quantizer_type == "fvq":
VQ = FactorizedVectorQuantize
elif quantizer_type == "lfq":
VQ = LookupFreeQuantize
else:
raise ValueError(f"Unknown quantizer type {quantizer_type}")
self.quantizers = nn.ModuleList(
[
VQ(
input_dim=input_dim,
codebook_size=codebook_size,
codebook_dim=codebook_dim,
**kwargs,
)
for _ in range(num_quantizers)
]
)
def forward(self, z, n_quantizers: int = None):
"""
Parameters
----------
z : Tensor[B x D x T]
n_quantizers : int, optional
No. of quantizers to use
(n_quantizers < self.n_codebooks ex: for quantizer dropout)
Note: if `self.quantizer_dropout` is True, this argument is ignored
when in training mode, and a random number of quantizers is used.
Returns
-------
"quantized_out" : Tensor[B x D x T]
Quantized continuous representation of input
"all_indices" : Tensor[N x B x T]
Codebook indices for each codebook
(quantized discrete representation of input)
"all_commit_losses" : Tensor[N]
"all_codebook_losses" : Tensor[N]
"all_quantized" : Tensor[N x B x D x T]
"""
quantized_out = 0.0
residual = z
all_commit_losses = []
all_codebook_losses = []
all_indices = []
all_quantized = []
if n_quantizers is None:
n_quantizers = self.num_quantizers
if self.training:
n_quantizers = torch.ones((z.shape[0],)) * self.num_quantizers + 1
dropout = torch.randint(1, self.num_quantizers + 1, (z.shape[0],))
n_dropout = int(z.shape[0] * self.quantizer_dropout)
n_quantizers[:n_dropout] = dropout[:n_dropout]
n_quantizers = n_quantizers.to(z.device)
for i, quantizer in enumerate(self.quantizers):
if self.training is False and i >= n_quantizers:
break
z_q_i, commit_loss_i, codebook_loss_i, indices_i, z_e_i = quantizer(
residual
)
# Create mask to apply quantizer dropout
mask = (
torch.full((z.shape[0],), fill_value=i, device=z.device) < n_quantizers
)
quantized_out = quantized_out + z_q_i * mask[:, None, None]
residual = residual - z_q_i
commit_loss_i = (commit_loss_i * mask).mean()
codebook_loss_i = (codebook_loss_i * mask).mean()
all_commit_losses.append(commit_loss_i)
all_codebook_losses.append(codebook_loss_i)
all_indices.append(indices_i)
all_quantized.append(z_q_i)
all_commit_losses, all_codebook_losses, all_indices, all_quantized = map(
torch.stack,
(all_commit_losses, all_codebook_losses, all_indices, all_quantized),
)
return (
quantized_out,
all_indices,
all_commit_losses,
all_codebook_losses,
all_quantized,
)
def vq2emb(self, vq, n_quantizers=None):
quantized_out = 0.0
if n_quantizers is None:
n_quantizers = self.num_quantizers
for idx, quantizer in enumerate(self.quantizers):
if idx >= n_quantizers:
break
quantized_out += quantizer.vq2emb(vq[idx])
return quantized_out
def latent2dist(self, z, n_quantizers=None):
quantized_out = 0.0
residual = z
all_dists = []
all_indices = []
if n_quantizers is None:
n_quantizers = self.num_quantizers
for i, quantizer in enumerate(self.quantizers):
if self.training is False and i >= n_quantizers:
break
dist_i, indices_i, z_q_i = quantizer.latent2dist(residual)
all_dists.append(dist_i)
all_indices.append(indices_i)
quantized_out = quantized_out + z_q_i
residual = residual - z_q_i
all_dists = torch.stack(all_dists)
all_indices = torch.stack(all_indices)
return all_dists, all_indices
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