"""Implements Conv-TasNet with building blocks of it. Based on https://github.com/naplab/Conv-TasNet/tree/e66d82a8f956a69749ec8a4ae382217faa097c5c """ from typing import Optional, Tuple import torch class ConvBlock(torch.nn.Module): """1D Convolutional block. Args: io_channels (int): The number of input/output channels, hidden_channels (int): The number of channels in the internal layers, . kernel_size (int): The convolution kernel size of the middle layer,

. padding (int): Padding value of the convolution in the middle layer. dilation (int, optional): Dilation value of the convolution in the middle layer. no_redisual (bool, optional): Disable residual block/output. Note: This implementation corresponds to the "non-causal" setting in the paper. """ def __init__( self, io_channels: int, hidden_channels: int, kernel_size: int, padding: int, dilation: int = 1, no_residual: bool = False, ): super().__init__() self.conv_layers = torch.nn.Sequential( torch.nn.Conv1d(in_channels=io_channels, out_channels=hidden_channels, kernel_size=1), torch.nn.PReLU(), torch.nn.GroupNorm(num_groups=1, num_channels=hidden_channels, eps=1e-08), torch.nn.Conv1d( in_channels=hidden_channels, out_channels=hidden_channels, kernel_size=kernel_size, padding=padding, dilation=dilation, groups=hidden_channels, ), torch.nn.PReLU(), torch.nn.GroupNorm(num_groups=1, num_channels=hidden_channels, eps=1e-08), ) self.res_out = ( None if no_residual else torch.nn.Conv1d(in_channels=hidden_channels, out_channels=io_channels, kernel_size=1) ) self.skip_out = torch.nn.Conv1d(in_channels=hidden_channels, out_channels=io_channels, kernel_size=1) def forward(self, input: torch.Tensor) -> Tuple[Optional[torch.Tensor], torch.Tensor]: feature = self.conv_layers(input) if self.res_out is None: residual = None else: residual = self.res_out(feature) skip_out = self.skip_out(feature) return residual, skip_out class MaskGenerator(torch.nn.Module): """TCN (Temporal Convolution Network) Separation Module Generates masks for separation. Args: input_dim (int): Input feature dimension, . num_sources (int): The number of sources to separate. kernel_size (int): The convolution kernel size of conv blocks,

. num_featrs (int): Input/output feature dimenstion of conv blocks, . num_hidden (int): Intermediate feature dimention of conv blocks, num_layers (int): The number of conv blocks in one stack, . num_stacks (int): The number of conv block stacks, . msk_activate (str): The activation function of the mask output. Note: This implementation corresponds to the "non-causal" setting in the paper. """ def __init__( self, input_dim: int, num_sources: int, kernel_size: int, num_feats: int, num_hidden: int, num_layers: int, num_stacks: int, msk_activate: str, ): super().__init__() self.input_dim = input_dim self.num_sources = num_sources self.input_norm = torch.nn.GroupNorm(num_groups=1, num_channels=input_dim, eps=1e-8) self.input_conv = torch.nn.Conv1d(in_channels=input_dim, out_channels=num_feats, kernel_size=1) self.receptive_field = 0 self.conv_layers = torch.nn.ModuleList([]) for s in range(num_stacks): for l in range(num_layers): multi = 2**l self.conv_layers.append( ConvBlock( io_channels=num_feats, hidden_channels=num_hidden, kernel_size=kernel_size, dilation=multi, padding=multi, # The last ConvBlock does not need residual no_residual=(l == (num_layers - 1) and s == (num_stacks - 1)), ) ) self.receptive_field += kernel_size if s == 0 and l == 0 else (kernel_size - 1) * multi self.output_prelu = torch.nn.PReLU() self.output_conv = torch.nn.Conv1d( in_channels=num_feats, out_channels=input_dim * num_sources, kernel_size=1, ) if msk_activate == "sigmoid": self.mask_activate = torch.nn.Sigmoid() elif msk_activate == "relu": self.mask_activate = torch.nn.ReLU() else: raise ValueError(f"Unsupported activation {msk_activate}") def forward(self, input: torch.Tensor) -> torch.Tensor: """Generate separation mask. Args: input (torch.Tensor): 3D Tensor with shape [batch, features, frames] Returns: Tensor: shape [batch, num_sources, features, frames] """ batch_size = input.shape[0] feats = self.input_norm(input) feats = self.input_conv(feats) output = 0.0 for layer in self.conv_layers: residual, skip = layer(feats) if residual is not None: # the last conv layer does not produce residual feats = feats + residual output = output + skip output = self.output_prelu(output) output = self.output_conv(output) output = self.mask_activate(output) return output.view(batch_size, self.num_sources, self.input_dim, -1) class ConvTasNet(torch.nn.Module): """Conv-TasNet architecture introduced in *Conv-TasNet: Surpassing Ideal Time–Frequency Magnitude Masking for Speech Separation* :cite:`Luo_2019`. Note: This implementation corresponds to the "non-causal" setting in the paper. See Also: * :class:`torchaudio.pipelines.SourceSeparationBundle`: Source separation pipeline with pre-trained models. Args: num_sources (int, optional): The number of sources to split. enc_kernel_size (int, optional): The convolution kernel size of the encoder/decoder, . enc_num_feats (int, optional): The feature dimensions passed to mask generator, . msk_kernel_size (int, optional): The convolution kernel size of the mask generator,

. msk_num_feats (int, optional): The input/output feature dimension of conv block in the mask generator, . msk_num_hidden_feats (int, optional): The internal feature dimension of conv block of the mask generator, . msk_num_layers (int, optional): The number of layers in one conv block of the mask generator, . msk_num_stacks (int, optional): The numbr of conv blocks of the mask generator, . msk_activate (str, optional): The activation function of the mask output (Default: ``sigmoid``). """ def __init__( self, num_sources: int = 2, # encoder/decoder parameters enc_kernel_size: int = 16, enc_num_feats: int = 512, # mask generator parameters msk_kernel_size: int = 3, msk_num_feats: int = 128, msk_num_hidden_feats: int = 512, msk_num_layers: int = 8, msk_num_stacks: int = 3, msk_activate: str = "sigmoid", ): super().__init__() self.num_sources = num_sources self.enc_num_feats = enc_num_feats self.enc_kernel_size = enc_kernel_size self.enc_stride = enc_kernel_size // 2 self.encoder = torch.nn.Conv1d( in_channels=1, out_channels=enc_num_feats, kernel_size=enc_kernel_size, stride=self.enc_stride, padding=self.enc_stride, bias=False, ) self.mask_generator = MaskGenerator( input_dim=enc_num_feats, num_sources=num_sources, kernel_size=msk_kernel_size, num_feats=msk_num_feats, num_hidden=msk_num_hidden_feats, num_layers=msk_num_layers, num_stacks=msk_num_stacks, msk_activate=msk_activate, ) self.decoder = torch.nn.ConvTranspose1d( in_channels=enc_num_feats, out_channels=1, kernel_size=enc_kernel_size, stride=self.enc_stride, padding=self.enc_stride, bias=False, ) def _align_num_frames_with_strides(self, input: torch.Tensor) -> Tuple[torch.Tensor, int]: """Pad input Tensor so that the end of the input tensor corresponds with 1. (if kernel size is odd) the center of the last convolution kernel or 2. (if kernel size is even) the end of the first half of the last convolution kernel Assumption: The resulting Tensor will be padded with the size of stride (== kernel_width // 2) on the both ends in Conv1D |<--- k_1 --->| | | |<-- k_n-1 -->| | | | |<--- k_n --->| | | | | | | | | | | | v v v | |<---->|<--- input signal --->|<--->|<---->| stride PAD stride Args: input (torch.Tensor): 3D Tensor with shape (batch_size, channels==1, frames) Returns: Tensor: Padded Tensor int: Number of paddings performed """ batch_size, num_channels, num_frames = input.shape is_odd = self.enc_kernel_size % 2 num_strides = (num_frames - is_odd) // self.enc_stride num_remainings = num_frames - (is_odd + num_strides * self.enc_stride) if num_remainings == 0: return input, 0 num_paddings = self.enc_stride - num_remainings pad = torch.zeros( batch_size, num_channels, num_paddings, dtype=input.dtype, device=input.device, ) return torch.cat([input, pad], 2), num_paddings def forward(self, input: torch.Tensor) -> torch.Tensor: """Perform source separation. Generate audio source waveforms. Args: input (torch.Tensor): 3D Tensor with shape [batch, channel==1, frames] Returns: Tensor: 3D Tensor with shape [batch, channel==num_sources, frames] """ if input.ndim != 3 or input.shape[1] != 1: raise ValueError(f"Expected 3D tensor (batch, channel==1, frames). Found: {input.shape}") # B: batch size # L: input frame length # L': padded input frame length # F: feature dimension # M: feature frame length # S: number of sources padded, num_pads = self._align_num_frames_with_strides(input) # B, 1, L' batch_size, num_padded_frames = padded.shape[0], padded.shape[2] feats = self.encoder(padded) # B, F, M masked = self.mask_generator(feats) * feats.unsqueeze(1) # B, S, F, M masked = masked.view(batch_size * self.num_sources, self.enc_num_feats, -1) # B*S, F, M decoded = self.decoder(masked) # B*S, 1, L' output = decoded.view(batch_size, self.num_sources, num_padded_frames) # B, S, L' if num_pads > 0: output = output[..., :-num_pads] # B, S, L return output def conv_tasnet_base(num_sources: int = 2) -> ConvTasNet: r"""Builds non-causal version of :class:`~torchaudio.models.ConvTasNet`. The parameter settings follow the ones with the highest Si-SNR metirc score in the paper, except the mask activation function is changed from "sigmoid" to "relu" for performance improvement. Args: num_sources (int, optional): Number of sources in the output. (Default: 2) Returns: ConvTasNet: ConvTasNet model. """ return ConvTasNet( num_sources=num_sources, enc_kernel_size=16, enc_num_feats=512, msk_kernel_size=3, msk_num_feats=128, msk_num_hidden_feats=512, msk_num_layers=8, msk_num_stacks=3, msk_activate="relu", )