EchoScout-FourTask / code /omini /models /st_audio_encoder.py
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"""ST-Audio Encoder:时间分辨空间音频编码器(对齐 Oh et al. 2026)。
前端可配置(`audio_frontend`):
- "binaural"(默认):BinauralFeatureExtractor(2ch→logmel×2+IPD×2=4ch) →
conv_downsample(4→1)。conv_downsample/backbone/head(355)/fc_norm/pos_embed/cls_tokens
全继承 BAT `finetuned.pth`(双声道域,零迁移)——即论文 stage1+2 已由 BAT 训好,只需训 stage3。
**不建静态 DoA/dist 头**(stage1/2 跳过;静态定位 token 本就不进 LLM)。
- "foa":FOAFeatureExtractor(4ch→7ch) → foa_conv(7→1)(随机初始化,需 FOA 域 stage1+2)。
建 doa_head/dist_head(论文 stage2 的静态全局定位头)。
公共结构:12 层 backbone → 3 全局 token(semantic[/DoA/dist]) + 512 patch;patch reshape
[T'=64,F'=8] → 频率维平均 → 插值 40 bin → 2 层时序 self-attn → 逐 bin 动态头
(activity/direction/log-distance)。送 LLM = [semantic_token] ++ [40 temporal] = 41 token。
命名约定(ckpt 继承):binaural 前端 conv 用 `conv_downsample`(4→1) 以继承 finetuned.pth;
foa 前端 conv 用 `foa_conv`(7→1) 避开同名不同 shape 冲突(strict=False 仍会 raise size mismatch)。
"""
from dataclasses import dataclass
from functools import partial
from typing import Optional
import torch
import torch.nn as nn
import torch.nn.functional as F
from .binaural_features import BinauralFeatureExtractor
from .foa_features import FOAFeatureExtractor
from .spatial_ast import PatchEmbed_new, conv3x3
from .vision_transformer import Block, VisionTransformer
@dataclass
class STEncoderOutput:
audio_tokens: torch.Tensor # [B,41,768]
semantic_logits: torch.Tensor # [B,355]
class75_logits: torch.Tensor # [B,75]
activity: torch.Tensor # [B,40] logit
direction: torch.Tensor # [B,40,3] 单位向量
log_distance: torch.Tensor # [B,40]
doa_vec: Optional[torch.Tensor] = None # [B,3] 单位向量;仅 foa 前端(静态定位头)有
dist: Optional[torch.Tensor] = None # [B,1] log 距离;仅 foa 前端有
class STAudioEncoder(VisionTransformer):
def __init__(self, audio_frontend="binaural", num_classes=355, embed_dim=768,
depth=12, num_heads=12, audio_bins=40, temporal_layers=2,
mlp_ratio=4, qkv_bias=True, drop_path_rate=0.1, patch_size=16,
norm_layer=partial(nn.LayerNorm, eps=1e-6)):
super().__init__(
num_classes=num_classes, drop_path_rate=drop_path_rate,
patch_size=patch_size, embed_dim=embed_dim, depth=depth,
num_heads=num_heads, mlp_ratio=mlp_ratio, qkv_bias=qkv_bias,
norm_layer=norm_layer,
)
if audio_frontend not in ("binaural", "foa"):
raise ValueError(f"audio_frontend must be 'binaural' or 'foa', got {audio_frontend!r}")
self.audio_frontend = audio_frontend
img_size = (1024, 128)
self.audio_bins = audio_bins
# 3 个静态全局 token:semantic / DoA / distance(继承 finetuned.pth cls_tokens(1,3,768))
del self.cls_token
self.num_cls_tokens = 3
self.cls_tokens = nn.Parameter(torch.zeros(1, 3, embed_dim))
self.patch_embed = PatchEmbed_new(
img_size=img_size, patch_size=(16, 16), in_chans=1,
embed_dim=embed_dim, stride=16,
)
num_patches = self.patch_embed.num_patches # 64*8 = 512
self.patch_hw = self.patch_embed.patch_hw # (64, 8)
self.pos_embed = nn.Parameter(
torch.zeros(1, num_patches + 1, embed_dim), requires_grad=False
)
# 前端 + 通道下采样 conv(命名决定能否继承 finetuned.pth)
if audio_frontend == "binaural":
self.in_chans = 2
self.binaural = BinauralFeatureExtractor()
self.conv_downsample = nn.Sequential(conv3x3(4, 1), nn.BatchNorm2d(1), nn.GELU())
self.doa_head = None # stage1/2 跳过:无静态定位头
self.dist_head = None
else: # foa
self.in_chans = 4
self.foa = FOAFeatureExtractor()
self.foa_conv = nn.Sequential(conv3x3(7, 1), nn.BatchNorm2d(1), nn.GELU())
self.doa_head = nn.Linear(embed_dim, 3)
self.dist_head = nn.Linear(embed_dim, 1)
# 语义头 self.head(355) 与 fc_norm 继承自基类/ckpt
self.fc_norm = norm_layer(embed_dim)
self.class75_head = nn.Linear(embed_dim, 75)
# 时序分支(stage3 新增,随机初始化)
dpr = [0.0] * temporal_layers
self.temporal_blocks = nn.ModuleList([
Block(dim=embed_dim, num_heads=num_heads, mlp_ratio=mlp_ratio,
qkv_bias=qkv_bias, drop_path=dpr[i], norm_layer=norm_layer)
for i in range(temporal_layers)
])
self.act_head = nn.Linear(embed_dim, 1)
self.dir_head = nn.Linear(embed_dim, 3)
self.logdist_head = nn.Linear(embed_dim, 1)
del self.norm # 与原 Spatial-AST 一致:不在 backbone 末尾再 norm
def _frontend(self, waveforms):
if self.audio_frontend == "binaural":
return self.conv_downsample(self.binaural(waveforms)) # [B,1,1024,128]
return self.foa_conv(self.foa(waveforms)) # [B,1,1024,128]
def forward_backbone(self, waveforms):
if waveforms.dim() != 3 or waveforms.shape[1] != self.in_chans:
raise ValueError(
f"audio_frontend={self.audio_frontend!r} 需要 [B,{self.in_chans},T] 波形,"
f"收到 {tuple(waveforms.shape)}"
)
x = self._frontend(waveforms) # [B,1,1024,128]
x = self.patch_embed(x) # [B,512,768]
x = x + self.pos_embed[:, 1:, :]
cls = self.cls_tokens.expand(x.shape[0], -1, -1)
x = torch.cat([cls, x], dim=1) # [B,515,768]
x = self.pos_drop(x)
for blk in self.blocks:
x = blk(x)
return x # [B,515,768]
def forward(self, waveforms):
x = self.forward_backbone(waveforms)
B = x.shape[0]
sem_t, doa_t, dist_t = x[:, 0], x[:, 1], x[:, 2]
patches = x[:, 3:] # [B,512,768]
norm_sem = self.fc_norm(sem_t)
semantic_logits = self.head(norm_sem)
class75_logits = self.class75_head(norm_sem)
doa_vec = dist = None
if self.doa_head is not None: # 仅 foa 前端
doa_vec = F.normalize(self.doa_head(self.fc_norm(doa_t)), dim=-1)
dist = self.dist_head(self.fc_norm(dist_t))
# patch → [T'=64, F'=8] → 频率平均 → 插值 40 → 时序 self-attn
Tp, Fp = self.patch_hw
grid = patches.reshape(B, Tp, Fp, -1).mean(dim=2) # [B,64,768]
temporal = F.interpolate(
grid.transpose(1, 2), size=self.audio_bins,
mode="linear", align_corners=False,
).transpose(1, 2) # [B,40,768]
for blk in self.temporal_blocks:
temporal = blk(temporal)
activity = self.act_head(temporal).squeeze(-1) # [B,40]
direction = F.normalize(self.dir_head(temporal), dim=-1) # [B,40,3]
log_distance = self.logdist_head(temporal).squeeze(-1) # [B,40]
audio_tokens = torch.cat([sem_t.unsqueeze(1), temporal], dim=1) # [B,41,768]
return STEncoderOutput(
audio_tokens=audio_tokens,
semantic_logits=semantic_logits,
class75_logits=class75_logits,
activity=activity, direction=direction, log_distance=log_distance,
doa_vec=doa_vec, dist=dist,
)