EchoScout-FourTask / code /omini /models /spatial_ast.py
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"""Spatial-AST 音频前端的共享组件(torchlibrosa shim + conv/patch 工具)。
Vendored from SLAM-LLM's `src/slam_llm/models/SpatialAST/SpatialAST.py`.
原 `BinauralEncoder`(双声道编码器)与 `load_spatial_ast` 已随 ST-Audio Encoder
改造移除——本模块现在只保留被 `foa_features` / `st_audio_encoder` 复用的部件:
`_STFTBuffer` / `_LogmelFilterBankBuffer`(STFT/logmel shim)、`conv3x3`、
`PatchEmbed_new`。
torchlibrosa's `STFT` / `LogmelFilterBank` use `nn.Parameter.data = torch.Tensor(...)`
assignment in __init__, which crashes inside HF's `init_empty_weights()` and
DeepSpeed's `zero.Init()` contexts (the parameter has been moved to meta
device or partitioned, and in-place .data assignment from a real cpu tensor
mismatches). We provide drop-in replacements `_STFTBuffer` and
`_LogmelFilterBankBuffer` that use `register_buffer` for the (frozen) FFT
basis and mel filter — the math is byte-identical to torchlibrosa, only the
storage type differs, and buffers are not subject to accelerate's parameter
materialisation hook (when `include_buffers=False`, the default).
"""
import librosa
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from timm.models.layers import to_2tuple
# ---------------------------- torchlibrosa-compatible shims ----------------------------
def _dft_matrix(n: int) -> np.ndarray:
"""Same as torchlibrosa.stft.DFTBase.dft_matrix — returns (n, n) complex."""
x, y = np.meshgrid(np.arange(n), np.arange(n))
omega = np.exp(-2 * np.pi * 1j / n)
return np.power(omega, x * y)
class _STFTBuffer(nn.Module):
"""Drop-in replacement for torchlibrosa.stft.STFT using register_buffer.
Same fourier-basis math, same windowing, same conv1d compute, same output
shape `(batch, 1, time_steps, n_fft//2+1)` — bit-exact with torchlibrosa.
"""
def __init__(self, n_fft=2048, hop_length=None, win_length=None,
window='hann', center=True, pad_mode='reflect',
freeze_parameters=True):
super().__init__()
self.n_fft = n_fft
self.center = center
self.pad_mode = pad_mode
self.win_length = win_length if win_length is not None else n_fft
self.hop_length = hop_length if hop_length is not None else int(self.win_length // 4)
fft_window = librosa.filters.get_window(window, self.win_length, fftbins=True)
fft_window = librosa.util.pad_center(fft_window, size=n_fft)
W = _dft_matrix(n_fft)
out_channels = n_fft // 2 + 1
real_w = np.real(W[:, :out_channels] * fft_window[:, None]).T[:, None, :] # (n_freq, 1, n_fft)
imag_w = np.imag(W[:, :out_channels] * fft_window[:, None]).T[:, None, :]
self.register_buffer("conv_real_weight", torch.tensor(real_w, dtype=torch.float32))
self.register_buffer("conv_imag_weight", torch.tensor(imag_w, dtype=torch.float32))
def forward(self, input):
# input: (B, T)
x = input.unsqueeze(1) # (B, 1, T)
if self.center:
x = F.pad(x, (self.n_fft // 2, self.n_fft // 2), mode=self.pad_mode)
# Buffers stay fp32 by design (numerical stability of FFT basis); cast to
# input dtype on the fly so bf16 / fp16 audio flows work without `model.to`
# having converted them.
w_real = self.conv_real_weight.to(x.dtype)
w_imag = self.conv_imag_weight.to(x.dtype)
real = F.conv1d(x, w_real, stride=self.hop_length) # (B, n_freq, T')
imag = F.conv1d(x, w_imag, stride=self.hop_length)
real = real[:, None, :, :].transpose(2, 3) # (B, 1, T', n_freq)
imag = imag[:, None, :, :].transpose(2, 3)
return real, imag
class _LogmelFilterBankBuffer(nn.Module):
"""Drop-in replacement for torchlibrosa.stft.LogmelFilterBank using
register_buffer. Same mel matrix (librosa.filters.mel), same matmul, same
power_to_db. `self.melW` attribute exposed for code that reaches into it
(e.g. FOAFeatureExtractor uses it to apply mel to intensity features).
"""
def __init__(self, sr=22050, n_fft=2048, n_mels=64, fmin=0.0, fmax=None,
is_log=True, ref=1.0, amin=1e-10, top_db=80.0,
freeze_parameters=True):
super().__init__()
self.is_log = is_log
self.ref = ref
self.amin = amin
self.top_db = top_db
if fmax is None:
fmax = sr // 2
mel_np = librosa.filters.mel(
sr=sr, n_fft=n_fft, n_mels=n_mels, fmin=fmin, fmax=fmax,
).T # (n_freq, n_mels)
self.register_buffer("melW", torch.tensor(mel_np, dtype=torch.float32))
def forward(self, input):
# input: (..., n_freq) → output: (..., n_mels)
# Cast melW to input dtype on the fly (same rationale as _STFTBuffer).
mel = torch.matmul(input, self.melW.to(input.dtype))
if not self.is_log:
return mel
log_spec = 10.0 * torch.log10(torch.clamp(mel, min=self.amin))
log_spec = log_spec - 10.0 * float(np.log10(max(self.amin, self.ref)))
if self.top_db is not None:
log_spec = torch.clamp(log_spec, min=log_spec.max().item() - self.top_db)
return log_spec
# ---------------------------- shared conv / patch-embed helpers ----------------------------
def conv3x3(in_channels, out_channels, stride=1):
"3x3 convolution with padding"
return nn.Conv2d(in_channels, out_channels, kernel_size=3, stride=stride, padding=1, bias=False)
class PatchEmbed_new(nn.Module):
"""Flexible image-to-patch embedding (overlapping patches supported)."""
def __init__(self, img_size=224, patch_size=16, in_chans=3, embed_dim=768, stride=10):
super().__init__()
img_size = to_2tuple(img_size)
patch_size = to_2tuple(patch_size)
stride = to_2tuple(stride)
self.img_size = img_size
self.patch_size = patch_size
self.in_chans = in_chans
self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=stride)
# Conv2d output shape (padding=0, dilation=1, groups=1):
# out = floor((in - kernel) / stride) + 1
# We compute it analytically rather than running a dummy forward in
# __init__ — under DeepSpeed zero.Init the Conv2d weight has shape [0]
# (partitioned) and forward crashes with "weight should have at least
# three dimensions".
h = (img_size[0] - patch_size[0]) // stride[0] + 1
w = (img_size[1] - patch_size[1]) // stride[1] + 1
self.patch_hw = (h, w)
self.num_patches = h * w
def get_output_shape(self, img_size):
# Kept for backward-compat with any external caller; not used in __init__.
return self.proj(torch.randn(1, self.in_chans, img_size[0], img_size[1])).shape
def forward(self, x):
x = self.proj(x)
x = x.flatten(2)
x = x.transpose(1, 2)
return x