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demucs.py
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demucs.py
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# Copyright (c) Facebook, Inc. and its affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.
# author: adefossez
import math
import time
import torch as th
from torch import nn
from torch.nn import functional as F
from .resample import downsample2, upsample2
from .utils import capture_init
class BLSTM(nn.Module):
def __init__(self, dim, layers=2, bi=True):
super().__init__()
klass = nn.LSTM
self.lstm = klass(bidirectional=bi, num_layers=layers, hidden_size=dim, input_size=dim)
self.linear = None
if bi:
self.linear = nn.Linear(2 * dim, dim)
def forward(self, x, hidden=None):
x, hidden = self.lstm(x, hidden)
if self.linear:
x = self.linear(x)
return x, hidden
def rescale_conv(conv, reference):
std = conv.weight.std().detach()
scale = (std / reference)**0.5
conv.weight.data /= scale
if conv.bias is not None:
conv.bias.data /= scale
def rescale_module(module, reference):
for sub in module.modules():
if isinstance(sub, (nn.Conv1d, nn.ConvTranspose1d)):
rescale_conv(sub, reference)
class Demucs(nn.Module):
"""
Demucs speech enhancement model.
Args:
- chin (int): number of input channels.
- chout (int): number of output channels.
- hidden (int): number of initial hidden channels.
- depth (int): number of layers.
- kernel_size (int): kernel size for each layer.
- stride (int): stride for each layer.
- causal (bool): if false, uses BiLSTM instead of LSTM.
- resample (int): amount of resampling to apply to the input/output.
Can be one of 1, 2 or 4.
- growth (float): number of channels is multiplied by this for every layer.
- max_hidden (int): maximum number of channels. Can be useful to
control the size/speed of the model.
- normalize (bool): if true, normalize the input.
- glu (bool): if true uses GLU instead of ReLU in 1x1 convolutions.
- rescale (float): controls custom weight initialization.
See https://arxiv.org/abs/1911.13254.
- floor (float): stability flooring when normalizing.
- sample_rate (float): sample_rate used for training the model.
"""
@capture_init
def __init__(self,
chin=1,
chout=1,
hidden=48,
depth=5,
kernel_size=8,
stride=4,
causal=True,
resample=4,
growth=2,
max_hidden=10_000,
normalize=True,
glu=True,
rescale=0.1,
floor=1e-3,
sample_rate=16_000):
super().__init__()
if resample not in [1, 2, 4]:
raise ValueError("Resample should be 1, 2 or 4.")
self.chin = chin
self.chout = chout
self.hidden = hidden
self.depth = depth
self.kernel_size = kernel_size
self.stride = stride
self.causal = causal
self.floor = floor
self.resample = resample
self.normalize = normalize
self.sample_rate = sample_rate
self.encoder = nn.ModuleList()
self.decoder = nn.ModuleList()
activation = nn.GLU(1) if glu else nn.ReLU()
ch_scale = 2 if glu else 1
for index in range(depth):
encode = []
encode += [
nn.Conv1d(chin, hidden, kernel_size, stride),
nn.ReLU(),
nn.Conv1d(hidden, hidden * ch_scale, 1), activation,
]
self.encoder.append(nn.Sequential(*encode))
decode = []
decode += [
nn.Conv1d(hidden, ch_scale * hidden, 1), activation,
nn.ConvTranspose1d(hidden, chout, kernel_size, stride),
]
if index > 0:
decode.append(nn.ReLU())
self.decoder.insert(0, nn.Sequential(*decode))
chout = hidden
chin = hidden
hidden = min(int(growth * hidden), max_hidden)
self.lstm = BLSTM(chin, bi=not causal)
if rescale:
rescale_module(self, reference=rescale)
def valid_length(self, length):
"""
Return the nearest valid length to use with the model so that
there is no time steps left over in a convolutions, e.g. for all
layers, size of the input - kernel_size % stride = 0.
If the mixture has a valid length, the estimated sources
will have exactly the same length.
"""
length = math.ceil(length * self.resample)
for idx in range(self.depth):
length = math.ceil((length - self.kernel_size) / self.stride) + 1
length = max(length, 1)
for idx in range(self.depth):
length = (length - 1) * self.stride + self.kernel_size
length = int(math.ceil(length / self.resample))
return int(length)
@property
def total_stride(self):
return self.stride ** self.depth // self.resample
def forward(self, mix):
if mix.dim() == 2:
mix = mix.unsqueeze(1)
if self.normalize:
mono = mix.mean(dim=1, keepdim=True)
std = mono.std(dim=-1, keepdim=True)
mix = mix / (self.floor + std)
else:
std = 1
length = mix.shape[-1]
x = mix
x = F.pad(x, (0, self.valid_length(length) - length))
if self.resample == 2:
x = upsample2(x)
elif self.resample == 4:
x = upsample2(x)
x = upsample2(x)
skips = []
for encode in self.encoder:
x = encode(x)
skips.append(x)
x = x.permute(2, 0, 1)
x, _ = self.lstm(x)
x = x.permute(1, 2, 0)
for decode in self.decoder:
skip = skips.pop(-1)
x = x + skip[..., :x.shape[-1]]
x = decode(x)
if self.resample == 2:
x = downsample2(x)
elif self.resample == 4:
x = downsample2(x)
x = downsample2(x)
x = x[..., :length]
return std * x
def fast_conv(conv, x):
"""
Faster convolution evaluation if either kernel size is 1
or length of sequence is 1.
"""
batch, chin, length = x.shape
chout, chin, kernel = conv.weight.shape
assert batch == 1
if kernel == 1:
x = x.view(chin, length)
out = th.addmm(conv.bias.view(-1, 1),
conv.weight.view(chout, chin), x)
elif length == kernel:
x = x.view(chin * kernel, 1)
out = th.addmm(conv.bias.view(-1, 1),
conv.weight.view(chout, chin * kernel), x)
else:
out = conv(x)
return out.view(batch, chout, -1)
class DemucsStreamer:
"""
Streaming implementation for Demucs. It supports being fed with any amount
of audio at a time. You will get back as much audio as possible at that
point.
Args:
- demucs (Demucs): Demucs model.
- dry (float): amount of dry (e.g. input) signal to keep. 0 is maximum
noise removal, 1 just returns the input signal. Small values > 0
allows to limit distortions.
- num_frames (int): number of frames to process at once. Higher values
will increase overall latency but improve the real time factor.
- resample_lookahead (int): extra lookahead used for the resampling.
- resample_buffer (int): size of the buffer of previous inputs/outputs
kept for resampling.
"""
def __init__(self, demucs,
dry=0,
num_frames=1,
resample_lookahead=64,
resample_buffer=256):
device = next(iter(demucs.parameters())).device
self.demucs = demucs
self.lstm_state = None
self.conv_state = None
self.dry = dry
self.resample_lookahead = resample_lookahead
resample_buffer = min(demucs.total_stride, resample_buffer)
self.resample_buffer = resample_buffer
self.frame_length = demucs.valid_length(1) + demucs.total_stride * (num_frames - 1)
self.total_length = self.frame_length + self.resample_lookahead
self.stride = demucs.total_stride * num_frames
self.resample_in = th.zeros(demucs.chin, resample_buffer, device=device)
self.resample_out = th.zeros(demucs.chin, resample_buffer, device=device)
self.frames = 0
self.total_time = 0
self.variance = 0
self.pending = th.zeros(demucs.chin, 0, device=device)
bias = demucs.decoder[0][2].bias
weight = demucs.decoder[0][2].weight
chin, chout, kernel = weight.shape
self._bias = bias.view(-1, 1).repeat(1, kernel).view(-1, 1)
self._weight = weight.permute(1, 2, 0).contiguous()
def reset_time_per_frame(self):
self.total_time = 0
self.frames = 0
@property
def time_per_frame(self):
return self.total_time / self.frames
def flush(self):
"""
Flush remaining audio by padding it with zero and initialize the previous
status. Call this when you have no more input and want to get back the last
chunk of audio.
"""
self.lstm_state = None
self.conv_state = None
pending_length = self.pending.shape[1]
padding = th.zeros(self.demucs.chin, self.total_length, device=self.pending.device)
out = self.feed(padding)
return out[:, :pending_length]
def feed(self, wav):
"""
Apply the model to mix using true real time evaluation.
Normalization is done online as is the resampling.
"""
begin = time.time()
demucs = self.demucs
resample_buffer = self.resample_buffer
stride = self.stride
resample = demucs.resample
if wav.dim() != 2:
raise ValueError("input wav should be two dimensional.")
chin, _ = wav.shape
if chin != demucs.chin:
raise ValueError(f"Expected {demucs.chin} channels, got {chin}")
self.pending = th.cat([self.pending, wav], dim=1)
outs = []
while self.pending.shape[1] >= self.total_length:
self.frames += 1
frame = self.pending[:, :self.total_length]
dry_signal = frame[:, :stride]
if demucs.normalize:
mono = frame.mean(0)
variance = (mono**2).mean()
self.variance = variance / self.frames + (1 - 1 / self.frames) * self.variance
frame = frame / (demucs.floor + math.sqrt(self.variance))
padded_frame = th.cat([self.resample_in, frame], dim=-1)
self.resample_in[:] = frame[:, stride - resample_buffer:stride]
frame = padded_frame
if resample == 4:
frame = upsample2(upsample2(frame))
elif resample == 2:
frame = upsample2(frame)
frame = frame[:, resample * resample_buffer:] # remove pre sampling buffer
frame = frame[:, :resample * self.frame_length] # remove extra samples after window
out, extra = self._separate_frame(frame)
padded_out = th.cat([self.resample_out, out, extra], 1)
self.resample_out[:] = out[:, -resample_buffer:]
if resample == 4:
out = downsample2(downsample2(padded_out))
elif resample == 2:
out = downsample2(padded_out)
else:
out = padded_out
out = out[:, resample_buffer // resample:]
out = out[:, :stride]
if demucs.normalize:
out *= math.sqrt(self.variance)
out = self.dry * dry_signal + (1 - self.dry) * out
outs.append(out)
self.pending = self.pending[:, stride:]
self.total_time += time.time() - begin
if outs:
out = th.cat(outs, 1)
else:
out = th.zeros(chin, 0, device=wav.device)
return out
def _separate_frame(self, frame):
demucs = self.demucs
skips = []
next_state = []
first = self.conv_state is None
stride = self.stride * demucs.resample
x = frame[None]
for idx, encode in enumerate(demucs.encoder):
stride //= demucs.stride
length = x.shape[2]
if idx == demucs.depth - 1:
# This is sligthly faster for the last conv
x = fast_conv(encode[0], x)
x = encode[1](x)
x = fast_conv(encode[2], x)
x = encode[3](x)
else:
if not first:
prev = self.conv_state.pop(0)
prev = prev[..., stride:]
tgt = (length - demucs.kernel_size) // demucs.stride + 1
missing = tgt - prev.shape[-1]
offset = length - demucs.kernel_size - demucs.stride * (missing - 1)
x = x[..., offset:]
x = encode[1](encode[0](x))
x = fast_conv(encode[2], x)
x = encode[3](x)
if not first:
x = th.cat([prev, x], -1)
next_state.append(x)
skips.append(x)
x = x.permute(2, 0, 1)
x, self.lstm_state = demucs.lstm(x, self.lstm_state)
x = x.permute(1, 2, 0)
# In the following, x contains only correct samples, i.e. the one
# for which each time position is covered by two window of the upper layer.
# extra contains extra samples to the right, and is used only as a
# better padding for the online resampling.
extra = None
for idx, decode in enumerate(demucs.decoder):
skip = skips.pop(-1)
x += skip[..., :x.shape[-1]]
x = fast_conv(decode[0], x)
x = decode[1](x)
if extra is not None:
skip = skip[..., x.shape[-1]:]
extra += skip[..., :extra.shape[-1]]
extra = decode[2](decode[1](decode[0](extra)))
x = decode[2](x)
next_state.append(x[..., -demucs.stride:] - decode[2].bias.view(-1, 1))
if extra is None:
extra = x[..., -demucs.stride:]
else:
extra[..., :demucs.stride] += next_state[-1]
x = x[..., :-demucs.stride]
if not first:
prev = self.conv_state.pop(0)
x[..., :demucs.stride] += prev
if idx != demucs.depth - 1:
x = decode[3](x)
extra = decode[3](extra)
self.conv_state = next_state
return x[0], extra[0]
def test():
import argparse
parser = argparse.ArgumentParser(
"denoiser.demucs",
description="Benchmark the streaming Demucs implementation, "
"as well as checking the delta with the offline implementation.")
parser.add_argument("--depth", default=5, type=int)
parser.add_argument("--resample", default=4, type=int)
parser.add_argument("--hidden", default=48, type=int)
parser.add_argument("--sample_rate", default=16000, type=float)
parser.add_argument("--device", default="cpu")
parser.add_argument("-t", "--num_threads", type=int)
parser.add_argument("-f", "--num_frames", type=int, default=1)
args = parser.parse_args()
if args.num_threads:
th.set_num_threads(args.num_threads)
sr = args.sample_rate
sr_ms = sr / 1000
demucs = Demucs(depth=args.depth, hidden=args.hidden, resample=args.resample).to(args.device)
x = th.randn(1, int(sr * 4)).to(args.device)
out = demucs(x[None])[0]
streamer = DemucsStreamer(demucs, num_frames=args.num_frames)
out_rt = []
frame_size = streamer.total_length
with th.no_grad():
while x.shape[1] > 0:
out_rt.append(streamer.feed(x[:, :frame_size]))
x = x[:, frame_size:]
frame_size = streamer.demucs.total_stride
out_rt.append(streamer.flush())
out_rt = th.cat(out_rt, 1)
model_size = sum(p.numel() for p in demucs.parameters()) * 4 / 2**20
initial_lag = streamer.total_length / sr_ms
tpf = 1000 * streamer.time_per_frame
print(f"model size: {model_size:.1f}MB, ", end='')
print(f"delta batch/streaming: {th.norm(out - out_rt) / th.norm(out):.2%}")
print(f"initial lag: {initial_lag:.1f}ms, ", end='')
print(f"stride: {streamer.stride * args.num_frames / sr_ms:.1f}ms")
print(f"time per frame: {tpf:.1f}ms, ", end='')
print(f"RTF: {((1000 * streamer.time_per_frame) / (streamer.stride / sr_ms)):.2f}")
print(f"Total lag with computation: {initial_lag + tpf:.1f}ms")
if __name__ == "__main__":
test()