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# Copyright (c) 2024 Alibaba Inc (authors: Xiang Lyu, Zhihao Du) | |
# | |
# Licensed under the Apache License, Version 2.0 (the "License"); | |
# you may not use this file except in compliance with the License. | |
# You may obtain a copy of the License at | |
# | |
# http://www.apache.org/licenses/LICENSE-2.0 | |
# | |
# Unless required by applicable law or agreed to in writing, software | |
# distributed under the License is distributed on an "AS IS" BASIS, | |
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
# See the License for the specific language governing permissions and | |
# limitations under the License. | |
import torch | |
import torch.nn.functional as F | |
from matcha.models.components.flow_matching import BASECFM | |
class ConditionalCFM(BASECFM): | |
def __init__(self, in_channels, cfm_params, n_spks=1, spk_emb_dim=64, estimator: torch.nn.Module = None): | |
super().__init__( | |
n_feats=in_channels, | |
cfm_params=cfm_params, | |
n_spks=n_spks, | |
spk_emb_dim=spk_emb_dim, | |
) | |
self.t_scheduler = cfm_params.t_scheduler | |
self.training_cfg_rate = cfm_params.training_cfg_rate | |
self.inference_cfg_rate = cfm_params.inference_cfg_rate | |
in_channels = in_channels + (spk_emb_dim if n_spks > 0 else 0) | |
# Just change the architecture of the estimator here | |
self.estimator = estimator | |
def forward(self, mu, mask, n_timesteps, temperature=1.0, spks=None, cond=None): | |
"""Forward diffusion | |
Args: | |
mu (torch.Tensor): output of encoder | |
shape: (batch_size, n_feats, mel_timesteps) | |
mask (torch.Tensor): output_mask | |
shape: (batch_size, 1, mel_timesteps) | |
n_timesteps (int): number of diffusion steps | |
temperature (float, optional): temperature for scaling noise. Defaults to 1.0. | |
spks (torch.Tensor, optional): speaker ids. Defaults to None. | |
shape: (batch_size, spk_emb_dim) | |
cond: Not used but kept for future purposes | |
Returns: | |
sample: generated mel-spectrogram | |
shape: (batch_size, n_feats, mel_timesteps) | |
""" | |
z = torch.randn_like(mu) * temperature | |
t_span = torch.linspace(0, 1, n_timesteps + 1, device=mu.device, dtype=mu.dtype) | |
if self.t_scheduler == 'cosine': | |
t_span = 1 - torch.cos(t_span * 0.5 * torch.pi) | |
return self.solve_euler(z, t_span=t_span, mu=mu, mask=mask, spks=spks, cond=cond) | |
def solve_euler(self, x, t_span, mu, mask, spks, cond): | |
""" | |
Fixed euler solver for ODEs. | |
Args: | |
x (torch.Tensor): random noise | |
t_span (torch.Tensor): n_timesteps interpolated | |
shape: (n_timesteps + 1,) | |
mu (torch.Tensor): output of encoder | |
shape: (batch_size, n_feats, mel_timesteps) | |
mask (torch.Tensor): output_mask | |
shape: (batch_size, 1, mel_timesteps) | |
spks (torch.Tensor, optional): speaker ids. Defaults to None. | |
shape: (batch_size, spk_emb_dim) | |
cond: Not used but kept for future purposes | |
""" | |
t, _, dt = t_span[0], t_span[-1], t_span[1] - t_span[0] | |
t = t.unsqueeze(dim=0) | |
# I am storing this because I can later plot it by putting a debugger here and saving it to a file | |
# Or in future might add like a return_all_steps flag | |
sol = [] | |
for step in range(1, len(t_span)): | |
dphi_dt = self.forward_estimator(x, mask, mu, t, spks, cond) | |
# Classifier-Free Guidance inference introduced in VoiceBox | |
if self.inference_cfg_rate > 0: | |
cfg_dphi_dt = self.forward_estimator( | |
x, mask, | |
torch.zeros_like(mu), t, | |
torch.zeros_like(spks) if spks is not None else None, | |
torch.zeros_like(cond) | |
) | |
dphi_dt = ((1.0 + self.inference_cfg_rate) * dphi_dt - | |
self.inference_cfg_rate * cfg_dphi_dt) | |
x = x + dt * dphi_dt | |
t = t + dt | |
sol.append(x) | |
if step < len(t_span) - 1: | |
dt = t_span[step + 1] - t | |
return sol[-1] | |
def forward_estimator(self, x, mask, mu, t, spks, cond): | |
if self.estimator is not None: | |
return self.estimator.forward(x, mask, mu, t, spks, cond) | |
else: | |
assert self.training is False, 'tensorrt cannot be used in training' | |
bs = x.shape[0] | |
hs = x.shape[1] | |
seq_len = x.shape[2] | |
# assert bs == 1 and hs == 80 | |
ret = torch.empty_like(x) | |
self.estimator_context.set_input_shape("x", x.shape) | |
self.estimator_context.set_input_shape("mask", mask.shape) | |
self.estimator_context.set_input_shape("mu", mu.shape) | |
self.estimator_context.set_input_shape("t", t.shape) | |
self.estimator_context.set_input_shape("spks", spks.shape) | |
self.estimator_context.set_input_shape("cond", cond.shape) | |
bindings = [x.data_ptr(), mask.data_ptr(), mu.data_ptr(), t.data_ptr(), spks.data_ptr(), cond.data_ptr(), ret.data_ptr()] | |
names = ['x', 'mask', 'mu', 't', 'spks', 'cond', 'estimator_out'] | |
for i in range(len(bindings)): | |
self.estimator_context.set_tensor_address(names[i], bindings[i]) | |
handle = torch.cuda.current_stream().cuda_stream | |
self.estimator_context.execute_async_v3(stream_handle=handle) | |
return ret | |
def compute_loss(self, x1, mask, mu, spks=None, cond=None): | |
"""Computes diffusion loss | |
Args: | |
x1 (torch.Tensor): Target | |
shape: (batch_size, n_feats, mel_timesteps) | |
mask (torch.Tensor): target mask | |
shape: (batch_size, 1, mel_timesteps) | |
mu (torch.Tensor): output of encoder | |
shape: (batch_size, n_feats, mel_timesteps) | |
spks (torch.Tensor, optional): speaker embedding. Defaults to None. | |
shape: (batch_size, spk_emb_dim) | |
Returns: | |
loss: conditional flow matching loss | |
y: conditional flow | |
shape: (batch_size, n_feats, mel_timesteps) | |
""" | |
b, _, t = mu.shape | |
# random timestep | |
t = torch.rand([b, 1, 1], device=mu.device, dtype=mu.dtype) | |
if self.t_scheduler == 'cosine': | |
t = 1 - torch.cos(t * 0.5 * torch.pi) | |
# sample noise p(x_0) | |
z = torch.randn_like(x1) | |
y = (1 - (1 - self.sigma_min) * t) * z + t * x1 | |
u = x1 - (1 - self.sigma_min) * z | |
# during training, we randomly drop condition to trade off mode coverage and sample fidelity | |
if self.training_cfg_rate > 0: | |
cfg_mask = torch.rand(b, device=x1.device) > self.training_cfg_rate | |
mu = mu * cfg_mask.view(-1, 1, 1) | |
spks = spks * cfg_mask.view(-1, 1) | |
cond = cond * cfg_mask.view(-1, 1, 1) | |
pred = self.estimator(y, mask, mu, t.squeeze(), spks, cond) | |
loss = F.mse_loss(pred * mask, u * mask, reduction="sum") / (torch.sum(mask) * u.shape[1]) | |
return loss, y | |