Python runtime 对齐发布规范：NPU 默认、依赖补全、前 5 帧置零

README.md

@@ -53,6 +53,10 @@ pip install axengine-x.x.x-py3-none-any.whl
 pip install -r requirements.txt
 ```
 
+`requirements.txt` 已包含 axengine（pyaxengine）wheel 依赖，直接
+`pip install -r requirements.txt` 即可。`--backend onnx`（CPU 回退）仅用于
+开发/验证，发布运行请使用默认 `axengine`（NPU）。
+
 AX650：
 
 ```bash

requirements.txt

@@ -1 +1,3 @@
 numpy>=1.24
+# AX 芯片 NPU 推理引擎（pyaxengine；GitHub Releases 包名为 axengine，板端必需）
+axengine @ https://github.com/AXERA-TECH/pyaxengine/releases/download/0.1.3.rc3/axengine-0.1.3-py3-none-any.whl

scripts/openwakeword_ax.py

@@ -162,6 +162,7 @@ def infer_clip(
     mel_buffer = np.ones((76, 32), dtype=np.float32)
     feature_buffer = np.zeros((34, 96), dtype=np.float32)
     scores: dict[str, list[list[float]]] = {name: [] for name in CLASSIFIERS}
+    frame_index = 0
 
     for start in range(0, samples.size, 1280):
         chunk = samples[start : start + 1280]
@@ -206,6 +207,11 @@ def infer_clip(
                 classifier.run({classifier.inputs[0].name: classifier_input}),
             )
             scores[name].append(np.asarray(output).reshape(-1).tolist())
+        # 对齐 openwakeword 官方行为：前 5 帧为初始化窗口，得分置零
+        if frame_index < 5:
+            for name in CLASSIFIERS:
+                scores[name][-1] = [0.0] * len(scores[name][-1])
+        frame_index += 1
 
     max_scores = {
         name: np.max(np.asarray(values, dtype=np.float64), axis=0).tolist()
@@ -260,7 +266,13 @@ def main(
     target_hardware: str = "AX650",
 ) -> None:
     parser = argparse.ArgumentParser()
-    parser.add_argument("--backend", choices=("axengine", "onnx"), default="axengine")
+    parser.add_argument(
+        "--backend",
+        choices=("axengine", "onnx"),
+        default="axengine",
+        help="推理后端：axengine=NPU（发布默认，仅板端可用）；"
+             "onnx=CPU 仅用于开发/验证，不属于发布运行路径",
+    )
     parser.add_argument("--mel-backend", choices=("numpy", "model"), default="numpy")
     parser.add_argument("--mel-weights", type=Path, default=DEFAULT_MEL_WEIGHTS)
     parser.add_argument("--models-dir", type=Path, default=default_models_dir)

scripts/runtime.py

@@ -65,7 +65,8 @@ class InferenceSession:
                 raise RuntimeError(
                     "axengine is unavailable; run this backend on an AXERA board"
                 ) from error
-            self._session = axengine.InferenceSession(str(self.path))
+            self._session = axengine.InferenceSession(
+                str(self.path), providers=["AxEngineExecutionProvider"])
         elif backend == "onnx":
             try:
                 import onnxruntime as ort