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Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

bolt_pet/audio/barge_in.py

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+"""Barge-in: notice that the user started talking *while the pet is talking*
+so playback can be cut short mid-sentence.
+
+Deliberately dumber than the utterance VAD in mic.py. The mic hears the pet's
+own voice coming back out of the speakers, so a single loud frame proves
+nothing — this requires several consecutive frames well above the normal
+speech threshold (BARGE_IN_RMS_THRESHOLD defaults to 4x VAD_RMS_THRESHOLD).
+Takes the same injectable stream shape as mic.record_utterance, so tests feed
+it fake frames instead of real audio hardware.
+"""
+
+from __future__ import annotations
+
+import numpy as np
+
+from .. import config
+from .mic import AudioStream, rms
+
+
+class BargeInDetector:
+    """Poll-driven: call check() repeatedly while audio plays. Each call
+    consumes exactly one mic frame (80ms at the default frame length), which
+    is also what paces the playback loop's polling."""
+
+    def __init__(
+        self,
+        stream: AudioStream,
+        threshold: int = None,
+        required_frames: int = None,
+        frame_len: int = config.FRAME_LEN,
+    ):
+        self._stream = stream
+        self._threshold = config.BARGE_IN_RMS_THRESHOLD if threshold is None else threshold
+        self._required = max(1, config.BARGE_IN_FRAMES if required_frames is None else required_frames)
+        self._frame_len = frame_len
+        self._loud_frames = 0
+
+    @property
+    def loud_frames(self) -> int:
+        return self._loud_frames
+
+    def reset(self) -> None:
+        self._loud_frames = 0
+
+    def check(self) -> bool:
+        """True once the user has been loud for long enough to count as an
+        interruption. Never raises: a mic hiccup mid-playback should not kill
+        the reply, it should just mean "no barge-in this frame"."""
+        try:
+            chunk, _ = self._stream.read(self._frame_len)
+        except Exception:
+            return False
+        frame = np.asarray(chunk)
+        if frame.ndim > 1:
+            frame = frame[:, 0]
+        if frame.size == 0:
+            return False
+        if rms(frame) >= self._threshold:
+            self._loud_frames += 1
+        else:
+            self._loud_frames = 0  # a single thump/cough shouldn't count
+        return self._loud_frames >= self._required