Initial commit

This commit is contained in:
王新升
2026-02-06 20:31:14 +08:00
parent a0b51be095
commit c589bcb837
145 changed files with 28773 additions and 0 deletions
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from .bs_roformer import BSRoformer
from .mel_band_roformer import MelBandRoformer
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from functools import wraps
from packaging import version
from collections import namedtuple
import os
import torch
from torch import nn, einsum
import torch.nn.functional as F
from einops import rearrange, reduce
# constants
FlashAttentionConfig = namedtuple('FlashAttentionConfig', ['enable_flash', 'enable_math', 'enable_mem_efficient'])
# helpers
def exists(val):
return val is not None
def default(v, d):
return v if exists(v) else d
def once(fn):
called = False
@wraps(fn)
def inner(x):
nonlocal called
if called:
return
called = True
return fn(x)
return inner
print_once = once(print)
# main class
class Attend(nn.Module):
def __init__(
self,
dropout = 0.,
flash = False,
scale = None
):
super().__init__()
self.scale = scale
self.dropout = dropout
self.attn_dropout = nn.Dropout(dropout)
self.flash = flash
assert not (flash and version.parse(torch.__version__) < version.parse('2.0.0')), 'in order to use flash attention, you must be using pytorch 2.0 or above'
# determine efficient attention configs for cuda and cpu
self.cpu_config = FlashAttentionConfig(True, True, True)
self.cuda_config = None
if not torch.cuda.is_available() or not flash:
return
device_properties = torch.cuda.get_device_properties(torch.device('cuda'))
device_version = version.parse(f'{device_properties.major}.{device_properties.minor}')
if device_version >= version.parse('8.0'):
if os.name == 'nt':
print_once('Windows OS detected, using math or mem efficient attention if input tensor is on cuda')
self.cuda_config = FlashAttentionConfig(False, True, True)
else:
print_once('GPU Compute Capability equal or above 8.0, using flash attention if input tensor is on cuda')
self.cuda_config = FlashAttentionConfig(True, False, False)
else:
print_once('GPU Compute Capability below 8.0, using math or mem efficient attention if input tensor is on cuda')
self.cuda_config = FlashAttentionConfig(False, True, True)
def flash_attn(self, q, k, v):
_, heads, q_len, _, k_len, is_cuda, device = *q.shape, k.shape[-2], q.is_cuda, q.device
if exists(self.scale):
default_scale = q.shape[-1] ** -0.5
q = q * (self.scale / default_scale)
# Check if there is a compatible device for flash attention
config = self.cuda_config if is_cuda else self.cpu_config
# pytorch 2.0 flash attn: q, k, v, mask, dropout, softmax_scale
with torch.backends.cuda.sdp_kernel(**config._asdict()):
out = F.scaled_dot_product_attention(
q, k, v,
dropout_p = self.dropout if self.training else 0.
)
return out
def forward(self, q, k, v):
"""
einstein notation
b - batch
h - heads
n, i, j - sequence length (base sequence length, source, target)
d - feature dimension
"""
q_len, k_len, device = q.shape[-2], k.shape[-2], q.device
scale = default(self.scale, q.shape[-1] ** -0.5)
if self.flash:
return self.flash_attn(q, k, v)
# similarity
sim = einsum(f"b h i d, b h j d -> b h i j", q, k) * scale
# attention
attn = sim.softmax(dim=-1)
attn = self.attn_dropout(attn)
# aggregate values
out = einsum(f"b h i j, b h j d -> b h i d", attn, v)
return out
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from functools import wraps
from packaging import version
from collections import namedtuple
import os
import torch
from torch import nn, einsum
import torch.nn.functional as F
from einops import rearrange, reduce
def _print_once(msg):
printed = False
@wraps(print)
def inner():
nonlocal printed
if not printed:
print(msg)
printed = True
return inner
try:
from sageattention import sageattn
_has_sage_attention = True
# _print_sage_found = _print_once("SageAttention found. Will be used when flash=True.")
# _print_sage_found()
except ImportError:
_has_sage_attention = False
_print_sage_not_found = _print_once("SageAttention not found. Will fall back to PyTorch SDPA (if available) or manual einsum.")
_print_sage_not_found()
# helpers
def exists(val):
return val is not None
def default(v, d):
return v if exists(v) else d
# main class
class Attend(nn.Module):
def __init__(
self,
dropout = 0.,
flash = False, # If True, attempts to use SageAttention or PyTorch SDPA
scale = None
):
super().__init__()
self.scale = scale # Store the scale if needed for einsum path
self.dropout = dropout # Store dropout if needed for einsum/SDPA path
# Determine which attention mechanism to *try* first
self.use_sage = flash and _has_sage_attention
self.use_pytorch_sdpa = False
self._sdpa_checked = False # Flag to check PyTorch version only once
if flash and not self.use_sage:
# Only consider PyTorch SDPA if Sage isn't available/chosen
if not self._sdpa_checked:
if version.parse(torch.__version__) >= version.parse('2.0.0'):
self.use_pytorch_sdpa = True
_print_sdpa_used = _print_once("Using PyTorch SDPA backend (FlashAttention-2, Memory-Efficient, or Math).")
_print_sdpa_used()
else:
_print_fallback_einsum = _print_once("Flash attention requested but Pytorch < 2.0 and SageAttention not found. Falling back to einsum.")
_print_fallback_einsum()
self._sdpa_checked = True
# Dropout layer for manual einsum implementation ONLY
# SDPA and SageAttention handle dropout differently (or not at all in Sage's base API)
self.attn_dropout = nn.Dropout(dropout)
def forward(self, q, k, v):
"""
einstein notation
b - batch
h - heads
n, i, j - sequence length (base sequence length, source, target)
d - feature dimension
Input tensors q, k, v expected in shape: (batch, heads, seq_len, dim_head) -> HND layout
"""
q_len, k_len, device = q.shape[-2], k.shape[-2], q.device
# --- Priority 1: SageAttention ---
if self.use_sage:
# Assumes q, k, v are FP16/BF16 (handled by autocast upstream)
# Assumes scale is handled internally by sageattn
# Assumes dropout is NOT handled by sageattn kernel
# is_causal=False based on how Attend is called in mel_band_roformer
out = sageattn(q, k, v, tensor_layout='HND', is_causal=False)
return out
try:
return out
# print("Attempting SageAttention") # Optional: for debugging
out = sageattn(q, k, v, tensor_layout='HND', is_causal=False)
return out
except Exception as e:
print(f"SageAttention failed with error: {e}. Falling back.")
self.use_sage = False # Don't try Sage again if it failed once
# Decide fallback: Check if PyTorch SDPA is an option
if not self._sdpa_checked:
if version.parse(torch.__version__) >= version.parse('2.0.0'):
self.use_pytorch_sdpa = True
_print_sdpa_fallback = _print_once("Falling back to PyTorch SDPA.")
_print_sdpa_fallback()
else:
_print_einsum_fallback = _print_once("Falling back to einsum.")
_print_einsum_fallback()
self._sdpa_checked = True
# --- Priority 2: PyTorch SDPA ---
if self.use_pytorch_sdpa:
# Use PyTorch's Scaled Dot Product Attention (SDPA)
# It handles scaling and dropout internally.
try:
# print("Attempting PyTorch SDPA") # Optional: for debugging
# Let PyTorch choose the best backend (Flash V2, Mem Efficient, Math)
with torch.backends.cuda.sdp_kernel(enable_flash=True, enable_math=True, enable_mem_efficient=True):
out = F.scaled_dot_product_attention(
q, k, v,
attn_mask=None, # Assuming no explicit mask needed here
dropout_p = self.dropout if self.training else 0.,
is_causal=False # Assuming not needed based on usage context
)
return out
except Exception as e:
print(f"PyTorch SDPA failed with error: {e}. Falling back to einsum.")
self.use_pytorch_sdpa = False # Fallback to einsum on error
# Calculate scale
scale = default(self.scale, q.shape[-1] ** -0.5)
# similarity
sim = einsum(f"b h i d, b h j d -> b h i j", q, k) * scale
# attention
attn = sim.softmax(dim=-1)
attn = self.attn_dropout(attn) # Apply dropout ONLY in einsum path
# aggregate values
out = einsum(f"b h i j, b h j d -> b h i d", attn, v)
return out
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from functools import partial
import torch
from torch import nn, einsum, Tensor
from torch.nn import Module, ModuleList
import torch.nn.functional as F
from .attend import Attend
try:
from .attend_sage import Attend as AttendSage
except:
pass
from torch.utils.checkpoint import checkpoint
from beartype.typing import Tuple, Optional, List, Callable
from beartype import beartype
from rotary_embedding_torch import RotaryEmbedding
from einops import rearrange, pack, unpack
from einops.layers.torch import Rearrange
# helper functions
def exists(val):
return val is not None
def default(v, d):
return v if exists(v) else d
def pack_one(t, pattern):
return pack([t], pattern)
def unpack_one(t, ps, pattern):
return unpack(t, ps, pattern)[0]
# norm
def l2norm(t):
return F.normalize(t, dim = -1, p = 2)
class RMSNorm(Module):
def __init__(self, dim):
super().__init__()
self.scale = dim ** 0.5
self.gamma = nn.Parameter(torch.ones(dim))
def forward(self, x):
return F.normalize(x, dim=-1) * self.scale * self.gamma
# attention
class FeedForward(Module):
def __init__(
self,
dim,
mult=4,
dropout=0.
):
super().__init__()
dim_inner = int(dim * mult)
self.net = nn.Sequential(
RMSNorm(dim),
nn.Linear(dim, dim_inner),
nn.GELU(),
nn.Dropout(dropout),
nn.Linear(dim_inner, dim),
nn.Dropout(dropout)
)
def forward(self, x):
return self.net(x)
class Attention(Module):
def __init__(
self,
dim,
heads=8,
dim_head=64,
dropout=0.,
rotary_embed=None,
flash=True,
sage_attention=False,
):
super().__init__()
self.heads = heads
self.scale = dim_head ** -0.5
dim_inner = heads * dim_head
self.rotary_embed = rotary_embed
if sage_attention:
self.attend = AttendSage(flash=flash, dropout=dropout)
else:
self.attend = Attend(flash=flash, dropout=dropout)
self.norm = RMSNorm(dim)
self.to_qkv = nn.Linear(dim, dim_inner * 3, bias=False)
self.to_gates = nn.Linear(dim, heads)
self.to_out = nn.Sequential(
nn.Linear(dim_inner, dim, bias=False),
nn.Dropout(dropout)
)
def forward(self, x):
x = self.norm(x)
q, k, v = rearrange(self.to_qkv(x), 'b n (qkv h d) -> qkv b h n d', qkv=3, h=self.heads)
if exists(self.rotary_embed):
q = self.rotary_embed.rotate_queries_or_keys(q)
k = self.rotary_embed.rotate_queries_or_keys(k)
out = self.attend(q, k, v)
gates = self.to_gates(x)
out = out * rearrange(gates, 'b n h -> b h n 1').sigmoid()
out = rearrange(out, 'b h n d -> b n (h d)')
return self.to_out(out)
class LinearAttention(Module):
"""
this flavor of linear attention proposed in https://arxiv.org/abs/2106.09681 by El-Nouby et al.
"""
@beartype
def __init__(
self,
*,
dim,
dim_head=32,
heads=8,
scale=8,
flash=False,
dropout=0.,
sage_attention=False,
):
super().__init__()
dim_inner = dim_head * heads
self.norm = RMSNorm(dim)
self.to_qkv = nn.Sequential(
nn.Linear(dim, dim_inner * 3, bias=False),
Rearrange('b n (qkv h d) -> qkv b h d n', qkv=3, h=heads)
)
self.temperature = nn.Parameter(torch.ones(heads, 1, 1))
if sage_attention:
self.attend = AttendSage(
scale=scale,
dropout=dropout,
flash=flash
)
else:
self.attend = Attend(
scale=scale,
dropout=dropout,
flash=flash
)
self.to_out = nn.Sequential(
Rearrange('b h d n -> b n (h d)'),
nn.Linear(dim_inner, dim, bias=False)
)
def forward(
self,
x
):
x = self.norm(x)
q, k, v = self.to_qkv(x)
q, k = map(l2norm, (q, k))
q = q * self.temperature.exp()
out = self.attend(q, k, v)
return self.to_out(out)
class Transformer(Module):
def __init__(
self,
*,
dim,
depth,
dim_head=64,
heads=8,
attn_dropout=0.,
ff_dropout=0.,
ff_mult=4,
norm_output=True,
rotary_embed=None,
flash_attn=True,
linear_attn=False,
sage_attention=False,
):
super().__init__()
self.layers = ModuleList([])
for _ in range(depth):
if linear_attn:
attn = LinearAttention(
dim=dim,
dim_head=dim_head,
heads=heads,
dropout=attn_dropout,
flash=flash_attn,
sage_attention=sage_attention
)
else:
attn = Attention(
dim=dim,
dim_head=dim_head,
heads=heads,
dropout=attn_dropout,
rotary_embed=rotary_embed,
flash=flash_attn,
sage_attention=sage_attention
)
self.layers.append(ModuleList([
attn,
FeedForward(dim=dim, mult=ff_mult, dropout=ff_dropout)
]))
self.norm = RMSNorm(dim) if norm_output else nn.Identity()
def forward(self, x):
for attn, ff in self.layers:
x = attn(x) + x
x = ff(x) + x
return self.norm(x)
# bandsplit module
class BandSplit(Module):
@beartype
def __init__(
self,
dim,
dim_inputs: Tuple[int, ...]
):
super().__init__()
self.dim_inputs = dim_inputs
self.to_features = ModuleList([])
for dim_in in dim_inputs:
net = nn.Sequential(
RMSNorm(dim_in),
nn.Linear(dim_in, dim)
)
self.to_features.append(net)
def forward(self, x):
x = x.split(self.dim_inputs, dim=-1)
outs = []
for split_input, to_feature in zip(x, self.to_features):
split_output = to_feature(split_input)
outs.append(split_output)
return torch.stack(outs, dim=-2)
def MLP(
dim_in,
dim_out,
dim_hidden=None,
depth=1,
activation=nn.Tanh
):
dim_hidden = default(dim_hidden, dim_in)
net = []
dims = (dim_in, *((dim_hidden,) * (depth - 1)), dim_out)
for ind, (layer_dim_in, layer_dim_out) in enumerate(zip(dims[:-1], dims[1:])):
is_last = ind == (len(dims) - 2)
net.append(nn.Linear(layer_dim_in, layer_dim_out))
if is_last:
continue
net.append(activation())
return nn.Sequential(*net)
class MaskEstimator(Module):
@beartype
def __init__(
self,
dim,
dim_inputs: Tuple[int, ...],
depth,
mlp_expansion_factor=4
):
super().__init__()
self.dim_inputs = dim_inputs
self.to_freqs = ModuleList([])
dim_hidden = dim * mlp_expansion_factor
for dim_in in dim_inputs:
net = []
mlp = nn.Sequential(
MLP(dim, dim_in * 2, dim_hidden=dim_hidden, depth=depth),
nn.GLU(dim=-1)
)
self.to_freqs.append(mlp)
def forward(self, x):
x = x.unbind(dim=-2)
outs = []
for band_features, mlp in zip(x, self.to_freqs):
freq_out = mlp(band_features)
outs.append(freq_out)
return torch.cat(outs, dim=-1)
# main class
DEFAULT_FREQS_PER_BANDS = (
2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
12, 12, 12, 12, 12, 12, 12, 12,
24, 24, 24, 24, 24, 24, 24, 24,
48, 48, 48, 48, 48, 48, 48, 48,
128, 129,
)
class BSRoformer(Module):
@beartype
def __init__(
self,
dim,
*,
depth,
stereo=False,
num_stems=1,
time_transformer_depth=2,
freq_transformer_depth=2,
linear_transformer_depth=0,
freqs_per_bands: Tuple[int, ...] = DEFAULT_FREQS_PER_BANDS,
# in the paper, they divide into ~60 bands, test with 1 for starters
dim_head=64,
heads=8,
attn_dropout=0.,
ff_dropout=0.,
flash_attn=True,
dim_freqs_in=1025,
stft_n_fft=2048,
stft_hop_length=512,
# 10ms at 44100Hz, from sections 4.1, 4.4 in the paper - @faroit recommends // 2 or // 4 for better reconstruction
stft_win_length=2048,
stft_normalized=False,
stft_window_fn: Optional[Callable] = None,
mask_estimator_depth=2,
multi_stft_resolution_loss_weight=1.,
multi_stft_resolutions_window_sizes: Tuple[int, ...] = (4096, 2048, 1024, 512, 256),
multi_stft_hop_size=147,
multi_stft_normalized=False,
multi_stft_window_fn: Callable = torch.hann_window,
mlp_expansion_factor=4,
use_torch_checkpoint=False,
skip_connection=False,
sage_attention=False,
):
super().__init__()
self.stereo = stereo
self.audio_channels = 2 if stereo else 1
self.num_stems = num_stems
self.use_torch_checkpoint = use_torch_checkpoint
self.skip_connection = skip_connection
self.layers = ModuleList([])
if sage_attention:
print("Use Sage Attention")
transformer_kwargs = dict(
dim=dim,
heads=heads,
dim_head=dim_head,
attn_dropout=attn_dropout,
ff_dropout=ff_dropout,
flash_attn=flash_attn,
norm_output=False,
sage_attention=sage_attention,
)
time_rotary_embed = RotaryEmbedding(dim=dim_head)
freq_rotary_embed = RotaryEmbedding(dim=dim_head)
for _ in range(depth):
tran_modules = []
if linear_transformer_depth > 0:
tran_modules.append(Transformer(depth=linear_transformer_depth, linear_attn=True, **transformer_kwargs))
tran_modules.append(
Transformer(depth=time_transformer_depth, rotary_embed=time_rotary_embed, **transformer_kwargs)
)
tran_modules.append(
Transformer(depth=freq_transformer_depth, rotary_embed=freq_rotary_embed, **transformer_kwargs)
)
self.layers.append(nn.ModuleList(tran_modules))
self.final_norm = RMSNorm(dim)
self.stft_kwargs = dict(
n_fft=stft_n_fft,
hop_length=stft_hop_length,
win_length=stft_win_length,
normalized=stft_normalized
)
self.stft_window_fn = partial(default(stft_window_fn, torch.hann_window), stft_win_length)
freqs = torch.stft(torch.randn(1, 4096), **self.stft_kwargs, window=torch.ones(stft_win_length), return_complex=True).shape[1]
assert len(freqs_per_bands) > 1
assert sum(
freqs_per_bands) == freqs, f'the number of freqs in the bands must equal {freqs} based on the STFT settings, but got {sum(freqs_per_bands)}'
freqs_per_bands_with_complex = tuple(2 * f * self.audio_channels for f in freqs_per_bands)
self.band_split = BandSplit(
dim=dim,
dim_inputs=freqs_per_bands_with_complex
)
self.mask_estimators = nn.ModuleList([])
for _ in range(num_stems):
mask_estimator = MaskEstimator(
dim=dim,
dim_inputs=freqs_per_bands_with_complex,
depth=mask_estimator_depth,
mlp_expansion_factor=mlp_expansion_factor,
)
self.mask_estimators.append(mask_estimator)
# for the multi-resolution stft loss
self.multi_stft_resolution_loss_weight = multi_stft_resolution_loss_weight
self.multi_stft_resolutions_window_sizes = multi_stft_resolutions_window_sizes
self.multi_stft_n_fft = stft_n_fft
self.multi_stft_window_fn = multi_stft_window_fn
self.multi_stft_kwargs = dict(
hop_length=multi_stft_hop_size,
normalized=multi_stft_normalized
)
def forward(
self,
raw_audio,
target=None,
return_loss_breakdown=False
):
"""
einops
b - batch
f - freq
t - time
s - audio channel (1 for mono, 2 for stereo)
n - number of 'stems'
c - complex (2)
d - feature dimension
"""
device = raw_audio.device
# defining whether model is loaded on MPS (MacOS GPU accelerator)
x_is_mps = True if device.type == "mps" else False
if raw_audio.ndim == 2:
raw_audio = rearrange(raw_audio, 'b t -> b 1 t')
channels = raw_audio.shape[1]
assert (not self.stereo and channels == 1) or (self.stereo and channels == 2), 'stereo needs to be set to True if passing in audio signal that is stereo (channel dimension of 2). also need to be False if mono (channel dimension of 1)'
# to stft
raw_audio, batch_audio_channel_packed_shape = pack_one(raw_audio, '* t')
stft_window = self.stft_window_fn(device=device)
# RuntimeError: FFT operations are only supported on MacOS 14+
# Since it's tedious to define whether we're on correct MacOS version - simple try-catch is used
try:
stft_repr = torch.stft(raw_audio, **self.stft_kwargs, window=stft_window, return_complex=True)
except:
stft_repr = torch.stft(raw_audio.cpu() if x_is_mps else raw_audio, **self.stft_kwargs,
window=stft_window.cpu() if x_is_mps else stft_window, return_complex=True).to(
device)
stft_repr = torch.view_as_real(stft_repr)
stft_repr = unpack_one(stft_repr, batch_audio_channel_packed_shape, '* f t c')
# merge stereo / mono into the frequency, with frequency leading dimension, for band splitting
stft_repr = rearrange(stft_repr,'b s f t c -> b (f s) t c')
x = rearrange(stft_repr, 'b f t c -> b t (f c)')
if self.use_torch_checkpoint:
x = checkpoint(self.band_split, x, use_reentrant=False)
else:
x = self.band_split(x)
# axial / hierarchical attention
store = [None] * len(self.layers)
for i, transformer_block in enumerate(self.layers):
if len(transformer_block) == 3:
linear_transformer, time_transformer, freq_transformer = transformer_block
x, ft_ps = pack([x], 'b * d')
if self.use_torch_checkpoint:
x = checkpoint(linear_transformer, x, use_reentrant=False)
else:
x = linear_transformer(x)
x, = unpack(x, ft_ps, 'b * d')
else:
time_transformer, freq_transformer = transformer_block
if self.skip_connection:
# Sum all previous
for j in range(i):
x = x + store[j]
x = rearrange(x, 'b t f d -> b f t d')
x, ps = pack([x], '* t d')
if self.use_torch_checkpoint:
x = checkpoint(time_transformer, x, use_reentrant=False)
else:
x = time_transformer(x)
x, = unpack(x, ps, '* t d')
x = rearrange(x, 'b f t d -> b t f d')
x, ps = pack([x], '* f d')
if self.use_torch_checkpoint:
x = checkpoint(freq_transformer, x, use_reentrant=False)
else:
x = freq_transformer(x)
x, = unpack(x, ps, '* f d')
if self.skip_connection:
store[i] = x
x = self.final_norm(x)
num_stems = len(self.mask_estimators)
if self.use_torch_checkpoint:
mask = torch.stack([checkpoint(fn, x, use_reentrant=False) for fn in self.mask_estimators], dim=1)
else:
mask = torch.stack([fn(x) for fn in self.mask_estimators], dim=1)
mask = rearrange(mask, 'b n t (f c) -> b n f t c', c=2)
# modulate frequency representation
stft_repr = rearrange(stft_repr, 'b f t c -> b 1 f t c')
# complex number multiplication
stft_repr = torch.view_as_complex(stft_repr)
mask = torch.view_as_complex(mask)
stft_repr = stft_repr * mask
# istft
stft_repr = rearrange(stft_repr, 'b n (f s) t -> (b n s) f t', s=self.audio_channels)
# same as torch.stft() fix for MacOS MPS above
try:
recon_audio = torch.istft(stft_repr, **self.stft_kwargs, window=stft_window, return_complex=False, length=raw_audio.shape[-1])
except:
recon_audio = torch.istft(stft_repr.cpu() if x_is_mps else stft_repr, **self.stft_kwargs, window=stft_window.cpu() if x_is_mps else stft_window, return_complex=False, length=raw_audio.shape[-1]).to(device)
recon_audio = rearrange(recon_audio, '(b n s) t -> b n s t', s=self.audio_channels, n=num_stems)
if num_stems == 1:
recon_audio = rearrange(recon_audio, 'b 1 s t -> b s t')
# if a target is passed in, calculate loss for learning
if not exists(target):
return recon_audio
if self.num_stems > 1:
assert target.ndim == 4 and target.shape[1] == self.num_stems
if target.ndim == 2:
target = rearrange(target, '... t -> ... 1 t')
target = target[..., :recon_audio.shape[-1]] # protect against lost length on istft
loss = F.l1_loss(recon_audio, target)
multi_stft_resolution_loss = 0.
for window_size in self.multi_stft_resolutions_window_sizes:
res_stft_kwargs = dict(
n_fft=max(window_size, self.multi_stft_n_fft), # not sure what n_fft is across multi resolution stft
win_length=window_size,
return_complex=True,
window=self.multi_stft_window_fn(window_size, device=device),
**self.multi_stft_kwargs,
)
recon_Y = torch.stft(rearrange(recon_audio, '... s t -> (... s) t'), **res_stft_kwargs)
target_Y = torch.stft(rearrange(target, '... s t -> (... s) t'), **res_stft_kwargs)
multi_stft_resolution_loss = multi_stft_resolution_loss + F.l1_loss(recon_Y, target_Y)
weighted_multi_resolution_loss = multi_stft_resolution_loss * self.multi_stft_resolution_loss_weight
total_loss = loss + weighted_multi_resolution_loss
if not return_loss_breakdown:
return total_loss
return total_loss, (loss, multi_stft_resolution_loss)
@@ -0,0 +1,703 @@
from functools import partial
import torch
from torch import nn, einsum, Tensor
from torch.nn import Module, ModuleList
import torch.nn.functional as F
from .attend import Attend
try:
from .attend_sage import Attend as AttendSage
except:
pass
from torch.utils.checkpoint import checkpoint
from beartype.typing import Tuple, Optional, List, Callable
from beartype import beartype
from rotary_embedding_torch import RotaryEmbedding
from einops import rearrange, pack, unpack, reduce, repeat
from einops.layers.torch import Rearrange
from librosa import filters
# helper functions
def exists(val):
return val is not None
def default(v, d):
return v if exists(v) else d
def pack_one(t, pattern):
return pack([t], pattern)
def unpack_one(t, ps, pattern):
return unpack(t, ps, pattern)[0]
def pad_at_dim(t, pad, dim=-1, value=0.):
dims_from_right = (- dim - 1) if dim < 0 else (t.ndim - dim - 1)
zeros = ((0, 0) * dims_from_right)
return F.pad(t, (*zeros, *pad), value=value)
def l2norm(t):
return F.normalize(t, dim=-1, p=2)
# norm
class RMSNorm(Module):
def __init__(self, dim):
super().__init__()
self.scale = dim ** 0.5
self.gamma = nn.Parameter(torch.ones(dim))
def forward(self, x):
return F.normalize(x, dim=-1) * self.scale * self.gamma
# attention
class FeedForward(Module):
def __init__(
self,
dim,
mult=4,
dropout=0.
):
super().__init__()
dim_inner = int(dim * mult)
self.net = nn.Sequential(
RMSNorm(dim),
nn.Linear(dim, dim_inner),
nn.GELU(),
nn.Dropout(dropout),
nn.Linear(dim_inner, dim),
nn.Dropout(dropout)
)
def forward(self, x):
return self.net(x)
class Attention(Module):
def __init__(
self,
dim,
heads=8,
dim_head=64,
dropout=0.,
rotary_embed=None,
flash=True,
sage_attention=False,
):
super().__init__()
self.heads = heads
self.scale = dim_head ** -0.5
dim_inner = heads * dim_head
self.rotary_embed = rotary_embed
if sage_attention:
self.attend = AttendSage(flash=flash, dropout=dropout)
else:
self.attend = Attend(flash=flash, dropout=dropout)
self.norm = RMSNorm(dim)
self.to_qkv = nn.Linear(dim, dim_inner * 3, bias=False)
self.to_gates = nn.Linear(dim, heads)
self.to_out = nn.Sequential(
nn.Linear(dim_inner, dim, bias=False),
nn.Dropout(dropout)
)
def forward(self, x):
x = self.norm(x)
q, k, v = rearrange(self.to_qkv(x), 'b n (qkv h d) -> qkv b h n d', qkv=3, h=self.heads)
if exists(self.rotary_embed):
q = self.rotary_embed.rotate_queries_or_keys(q)
k = self.rotary_embed.rotate_queries_or_keys(k)
out = self.attend(q, k, v)
gates = self.to_gates(x)
out = out * rearrange(gates, 'b n h -> b h n 1').sigmoid()
out = rearrange(out, 'b h n d -> b n (h d)')
return self.to_out(out)
class LinearAttention(Module):
"""
this flavor of linear attention proposed in https://arxiv.org/abs/2106.09681 by El-Nouby et al.
"""
@beartype
def __init__(
self,
*,
dim,
dim_head=32,
heads=8,
scale=8,
flash=False,
dropout=0.,
sage_attention=False
):
super().__init__()
dim_inner = dim_head * heads
self.norm = RMSNorm(dim)
self.to_qkv = nn.Sequential(
nn.Linear(dim, dim_inner * 3, bias=False),
Rearrange('b n (qkv h d) -> qkv b h d n', qkv=3, h=heads)
)
self.temperature = nn.Parameter(torch.ones(heads, 1, 1))
if sage_attention:
self.attend = AttendSage(
scale=scale,
dropout=dropout,
flash=flash
)
else:
self.attend = Attend(
scale=scale,
dropout=dropout,
flash=flash
)
self.to_out = nn.Sequential(
Rearrange('b h d n -> b n (h d)'),
nn.Linear(dim_inner, dim, bias=False)
)
def forward(
self,
x
):
x = self.norm(x)
q, k, v = self.to_qkv(x)
q, k = map(l2norm, (q, k))
q = q * self.temperature.exp()
out = self.attend(q, k, v)
return self.to_out(out)
class Transformer(Module):
def __init__(
self,
*,
dim,
depth,
dim_head=64,
heads=8,
attn_dropout=0.,
ff_dropout=0.,
ff_mult=4,
norm_output=True,
rotary_embed=None,
flash_attn=True,
linear_attn=False,
sage_attention=False,
):
super().__init__()
self.layers = ModuleList([])
for _ in range(depth):
if linear_attn:
attn = LinearAttention(
dim=dim,
dim_head=dim_head,
heads=heads,
dropout=attn_dropout,
flash=flash_attn,
sage_attention=sage_attention
)
else:
attn = Attention(
dim=dim,
dim_head=dim_head,
heads=heads,
dropout=attn_dropout,
rotary_embed=rotary_embed,
flash=flash_attn,
sage_attention=sage_attention
)
self.layers.append(ModuleList([
attn,
FeedForward(dim=dim, mult=ff_mult, dropout=ff_dropout)
]))
self.norm = RMSNorm(dim) if norm_output else nn.Identity()
def forward(self, x):
for attn, ff in self.layers:
x = attn(x) + x
x = ff(x) + x
return self.norm(x)
# bandsplit module
class BandSplit(Module):
@beartype
def __init__(
self,
dim,
dim_inputs: Tuple[int, ...]
):
super().__init__()
self.dim_inputs = dim_inputs
self.to_features = ModuleList([])
for dim_in in dim_inputs:
net = nn.Sequential(
RMSNorm(dim_in),
nn.Linear(dim_in, dim)
)
self.to_features.append(net)
def forward(self, x):
x = x.split(self.dim_inputs, dim=-1)
outs = []
for split_input, to_feature in zip(x, self.to_features):
split_output = to_feature(split_input)
outs.append(split_output)
return torch.stack(outs, dim=-2)
def MLP(
dim_in,
dim_out,
dim_hidden=None,
depth=1,
activation=nn.Tanh
):
dim_hidden = default(dim_hidden, dim_in)
net = []
dims = (dim_in, *((dim_hidden,) * depth), dim_out)
for ind, (layer_dim_in, layer_dim_out) in enumerate(zip(dims[:-1], dims[1:])):
is_last = ind == (len(dims) - 2)
net.append(nn.Linear(layer_dim_in, layer_dim_out))
if is_last:
continue
net.append(activation())
return nn.Sequential(*net)
class MaskEstimator(Module):
@beartype
def __init__(
self,
dim,
dim_inputs: Tuple[int, ...],
depth,
mlp_expansion_factor=4
):
super().__init__()
self.dim_inputs = dim_inputs
self.to_freqs = ModuleList([])
dim_hidden = dim * mlp_expansion_factor
for dim_in in dim_inputs:
net = []
mlp = nn.Sequential(
MLP(dim, dim_in * 2, dim_hidden=dim_hidden, depth=depth),
nn.GLU(dim=-1)
)
self.to_freqs.append(mlp)
def forward(self, x):
x = x.unbind(dim=-2)
outs = []
for band_features, mlp in zip(x, self.to_freqs):
freq_out = mlp(band_features)
outs.append(freq_out)
return torch.cat(outs, dim=-1)
# main class
class MelBandRoformer(Module):
@beartype
def __init__(
self,
dim,
*,
depth,
stereo=False,
num_stems=1,
time_transformer_depth=2,
freq_transformer_depth=2,
linear_transformer_depth=0,
num_bands=60,
dim_head=64,
heads=8,
attn_dropout=0.1,
ff_dropout=0.1,
flash_attn=True,
dim_freqs_in=1025,
sample_rate=44100, # needed for mel filter bank from librosa
stft_n_fft=2048,
stft_hop_length=512,
# 10ms at 44100Hz, from sections 4.1, 4.4 in the paper - @faroit recommends // 2 or // 4 for better reconstruction
stft_win_length=2048,
stft_normalized=False,
stft_window_fn: Optional[Callable] = None,
mask_estimator_depth=1,
multi_stft_resolution_loss_weight=1.,
multi_stft_resolutions_window_sizes: Tuple[int, ...] = (4096, 2048, 1024, 512, 256),
multi_stft_hop_size=147,
multi_stft_normalized=False,
multi_stft_window_fn: Callable = torch.hann_window,
match_input_audio_length=False, # if True, pad output tensor to match length of input tensor
mlp_expansion_factor=4,
use_torch_checkpoint=False,
skip_connection=False,
sage_attention=False,
):
super().__init__()
self.stereo = stereo
self.audio_channels = 2 if stereo else 1
self.num_stems = num_stems
self.use_torch_checkpoint = use_torch_checkpoint
self.skip_connection = skip_connection
self.layers = ModuleList([])
if sage_attention:
print("Use Sage Attention")
transformer_kwargs = dict(
dim=dim,
heads=heads,
dim_head=dim_head,
attn_dropout=attn_dropout,
ff_dropout=ff_dropout,
flash_attn=flash_attn,
sage_attention=sage_attention,
)
time_rotary_embed = RotaryEmbedding(dim=dim_head)
freq_rotary_embed = RotaryEmbedding(dim=dim_head)
for _ in range(depth):
tran_modules = []
if linear_transformer_depth > 0:
tran_modules.append(Transformer(depth=linear_transformer_depth, linear_attn=True, **transformer_kwargs))
tran_modules.append(
Transformer(depth=time_transformer_depth, rotary_embed=time_rotary_embed, **transformer_kwargs)
)
tran_modules.append(
Transformer(depth=freq_transformer_depth, rotary_embed=freq_rotary_embed, **transformer_kwargs)
)
self.layers.append(nn.ModuleList(tran_modules))
self.stft_window_fn = partial(default(stft_window_fn, torch.hann_window), stft_win_length)
self.stft_kwargs = dict(
n_fft=stft_n_fft,
hop_length=stft_hop_length,
win_length=stft_win_length,
normalized=stft_normalized
)
freqs = torch.stft(torch.randn(1, 4096), **self.stft_kwargs, window=torch.ones(stft_n_fft), return_complex=True).shape[1]
# create mel filter bank
# with librosa.filters.mel as in section 2 of paper
mel_filter_bank_numpy = filters.mel(sr=sample_rate, n_fft=stft_n_fft, n_mels=num_bands)
mel_filter_bank = torch.from_numpy(mel_filter_bank_numpy)
# for some reason, it doesn't include the first freq? just force a value for now
mel_filter_bank[0][0] = 1.
# In some systems/envs we get 0.0 instead of ~1.9e-18 in the last position,
# so let's force a positive value
mel_filter_bank[-1, -1] = 1.
# binary as in paper (then estimated masks are averaged for overlapping regions)
freqs_per_band = mel_filter_bank > 0
assert freqs_per_band.any(dim=0).all(), 'all frequencies need to be covered by all bands for now'
repeated_freq_indices = repeat(torch.arange(freqs), 'f -> b f', b=num_bands)
freq_indices = repeated_freq_indices[freqs_per_band]
if stereo:
freq_indices = repeat(freq_indices, 'f -> f s', s=2)
freq_indices = freq_indices * 2 + torch.arange(2)
freq_indices = rearrange(freq_indices, 'f s -> (f s)')
self.register_buffer('freq_indices', freq_indices, persistent=False)
self.register_buffer('freqs_per_band', freqs_per_band, persistent=False)
num_freqs_per_band = reduce(freqs_per_band, 'b f -> b', 'sum')
num_bands_per_freq = reduce(freqs_per_band, 'b f -> f', 'sum')
self.register_buffer('num_freqs_per_band', num_freqs_per_band, persistent=False)
self.register_buffer('num_bands_per_freq', num_bands_per_freq, persistent=False)
# band split and mask estimator
freqs_per_bands_with_complex = tuple(2 * f * self.audio_channels for f in num_freqs_per_band.tolist())
self.band_split = BandSplit(
dim=dim,
dim_inputs=freqs_per_bands_with_complex
)
self.mask_estimators = nn.ModuleList([])
for _ in range(num_stems):
mask_estimator = MaskEstimator(
dim=dim,
dim_inputs=freqs_per_bands_with_complex,
depth=mask_estimator_depth,
mlp_expansion_factor=mlp_expansion_factor,
)
self.mask_estimators.append(mask_estimator)
# for the multi-resolution stft loss
self.multi_stft_resolution_loss_weight = multi_stft_resolution_loss_weight
self.multi_stft_resolutions_window_sizes = multi_stft_resolutions_window_sizes
self.multi_stft_n_fft = stft_n_fft
self.multi_stft_window_fn = multi_stft_window_fn
self.multi_stft_kwargs = dict(
hop_length=multi_stft_hop_size,
normalized=multi_stft_normalized
)
self.match_input_audio_length = match_input_audio_length
def forward(
self,
raw_audio,
target=None,
return_loss_breakdown=False
):
"""
einops
b - batch
f - freq
t - time
s - audio channel (1 for mono, 2 for stereo)
n - number of 'stems'
c - complex (2)
d - feature dimension
"""
device = raw_audio.device
if raw_audio.ndim == 2:
raw_audio = rearrange(raw_audio, 'b t -> b 1 t')
batch, channels, raw_audio_length = raw_audio.shape
istft_length = raw_audio_length if self.match_input_audio_length else None
assert (not self.stereo and channels == 1) or (
self.stereo and channels == 2), 'stereo needs to be set to True if passing in audio signal that is stereo (channel dimension of 2). also need to be False if mono (channel dimension of 1)'
# to stft
raw_audio, batch_audio_channel_packed_shape = pack_one(raw_audio, '* t')
stft_window = self.stft_window_fn(device=device)
stft_repr = torch.stft(raw_audio, **self.stft_kwargs, window=stft_window, return_complex=True)
stft_repr = torch.view_as_real(stft_repr)
stft_repr = unpack_one(stft_repr, batch_audio_channel_packed_shape, '* f t c')
# merge stereo / mono into the frequency, with frequency leading dimension, for band splitting
stft_repr = rearrange(stft_repr,'b s f t c -> b (f s) t c')
# index out all frequencies for all frequency ranges across bands ascending in one go
batch_arange = torch.arange(batch, device=device)[..., None]
# account for stereo
x = stft_repr[batch_arange, self.freq_indices]
# fold the complex (real and imag) into the frequencies dimension
x = rearrange(x, 'b f t c -> b t (f c)')
if self.use_torch_checkpoint:
x = checkpoint(self.band_split, x, use_reentrant=False)
else:
x = self.band_split(x)
# axial / hierarchical attention
store = [None] * len(self.layers)
for i, transformer_block in enumerate(self.layers):
if len(transformer_block) == 3:
linear_transformer, time_transformer, freq_transformer = transformer_block
x, ft_ps = pack([x], 'b * d')
if self.use_torch_checkpoint:
x = checkpoint(linear_transformer, x, use_reentrant=False)
else:
x = linear_transformer(x)
x, = unpack(x, ft_ps, 'b * d')
else:
time_transformer, freq_transformer = transformer_block
if self.skip_connection:
# Sum all previous
for j in range(i):
x = x + store[j]
x = rearrange(x, 'b t f d -> b f t d')
x, ps = pack([x], '* t d')
if self.use_torch_checkpoint:
x = checkpoint(time_transformer, x, use_reentrant=False)
else:
x = time_transformer(x)
x, = unpack(x, ps, '* t d')
x = rearrange(x, 'b f t d -> b t f d')
x, ps = pack([x], '* f d')
if self.use_torch_checkpoint:
x = checkpoint(freq_transformer, x, use_reentrant=False)
else:
x = freq_transformer(x)
x, = unpack(x, ps, '* f d')
if self.skip_connection:
store[i] = x
num_stems = len(self.mask_estimators)
if self.use_torch_checkpoint:
masks = torch.stack([checkpoint(fn, x, use_reentrant=False) for fn in self.mask_estimators], dim=1)
else:
masks = torch.stack([fn(x) for fn in self.mask_estimators], dim=1)
masks = rearrange(masks, 'b n t (f c) -> b n f t c', c=2)
# modulate frequency representation
stft_repr = rearrange(stft_repr, 'b f t c -> b 1 f t c')
# complex number multiplication
stft_repr = torch.view_as_complex(stft_repr)
masks = torch.view_as_complex(masks)
masks = masks.type(stft_repr.dtype)
# need to average the estimated mask for the overlapped frequencies
scatter_indices = repeat(self.freq_indices, 'f -> b n f t', b=batch, n=num_stems, t=stft_repr.shape[-1])
stft_repr_expanded_stems = repeat(stft_repr, 'b 1 ... -> b n ...', n=num_stems)
masks_summed = torch.zeros_like(stft_repr_expanded_stems).scatter_add_(2, scatter_indices, masks)
denom = repeat(self.num_bands_per_freq, 'f -> (f r) 1', r=channels)
masks_averaged = masks_summed / denom.clamp(min=1e-8)
# modulate stft repr with estimated mask
stft_repr = stft_repr * masks_averaged
# istft
stft_repr = rearrange(stft_repr, 'b n (f s) t -> (b n s) f t', s=self.audio_channels)
recon_audio = torch.istft(stft_repr, **self.stft_kwargs, window=stft_window, return_complex=False,
length=istft_length)
recon_audio = rearrange(recon_audio, '(b n s) t -> b n s t', b=batch, s=self.audio_channels, n=num_stems)
if num_stems == 1:
recon_audio = rearrange(recon_audio, 'b 1 s t -> b s t')
# if a target is passed in, calculate loss for learning
if not exists(target):
return recon_audio
if self.num_stems > 1:
assert target.ndim == 4 and target.shape[1] == self.num_stems
if target.ndim == 2:
target = rearrange(target, '... t -> ... 1 t')
target = target[..., :recon_audio.shape[-1]] # protect against lost length on istft
loss = F.l1_loss(recon_audio, target)
multi_stft_resolution_loss = 0.
for window_size in self.multi_stft_resolutions_window_sizes:
res_stft_kwargs = dict(
n_fft=max(window_size, self.multi_stft_n_fft), # not sure what n_fft is across multi resolution stft
win_length=window_size,
return_complex=True,
window=self.multi_stft_window_fn(window_size, device=device),
**self.multi_stft_kwargs,
)
recon_Y = torch.stft(rearrange(recon_audio, '... s t -> (... s) t'), **res_stft_kwargs)
target_Y = torch.stft(rearrange(target, '... s t -> (... s) t'), **res_stft_kwargs)
multi_stft_resolution_loss = multi_stft_resolution_loss + F.l1_loss(recon_Y, target_Y)
weighted_multi_resolution_loss = multi_stft_resolution_loss * self.multi_stft_resolution_loss_weight
total_loss = loss + weighted_multi_resolution_loss
if not return_loss_breakdown:
return total_loss
return total_loss, (loss, multi_stft_resolution_loss)