Files
sideline/engine/mic.py
David Gwilliam 15de46722a refactor: phase 4 - event-driven architecture foundation
- Add EventBus class with pub/sub messaging (thread-safe)
- Add emitter Protocol classes (EventEmitter, Startable, Stoppable)
- Add event emission to NtfyPoller (NtfyMessageEvent)
- Add event emission to MicMonitor (MicLevelEvent)
- Update StreamController to publish stream start/end events
- Add comprehensive tests for eventbus and emitters modules
2026-03-15 19:15:08 -07:00

97 lines
2.7 KiB
Python

"""
Microphone input monitor — standalone, no internal dependencies.
Gracefully degrades if sounddevice/numpy are unavailable.
"""
import atexit
from collections.abc import Callable
from datetime import datetime
try:
import numpy as _np
import sounddevice as _sd
_HAS_MIC = True
except Exception:
_HAS_MIC = False
from engine.events import MicLevelEvent
class MicMonitor:
"""Background mic stream that exposes current RMS dB level."""
def __init__(self, threshold_db=50):
self.threshold_db = threshold_db
self._db = -99.0
self._stream = None
self._subscribers: list[Callable[[MicLevelEvent], None]] = []
@property
def available(self):
"""True if sounddevice is importable."""
return _HAS_MIC
@property
def db(self):
"""Current RMS dB level."""
return self._db
@property
def excess(self):
"""dB above threshold (clamped to 0)."""
return max(0.0, self._db - self.threshold_db)
def subscribe(self, callback: Callable[[MicLevelEvent], None]) -> None:
"""Register a callback to be called when mic level changes."""
self._subscribers.append(callback)
def unsubscribe(self, callback: Callable[[MicLevelEvent], None]) -> None:
"""Remove a registered callback."""
if callback in self._subscribers:
self._subscribers.remove(callback)
def _emit(self, event: MicLevelEvent) -> None:
"""Emit an event to all subscribers."""
for cb in self._subscribers:
try:
cb(event)
except Exception:
pass
def start(self):
"""Start background mic stream. Returns True on success, False/None otherwise."""
if not _HAS_MIC:
return None
def _cb(indata, frames, t, status):
rms = float(_np.sqrt(_np.mean(indata**2)))
self._db = 20 * _np.log10(rms) if rms > 0 else -99.0
if self._subscribers:
event = MicLevelEvent(
db_level=self._db,
excess_above_threshold=max(0.0, self._db - self.threshold_db),
timestamp=datetime.now(),
)
self._emit(event)
try:
self._stream = _sd.InputStream(
callback=_cb, channels=1, samplerate=44100, blocksize=2048
)
self._stream.start()
atexit.register(self.stop)
return True
except Exception:
return False
def stop(self):
"""Stop the mic stream if running."""
if self._stream:
try:
self._stream.stop()
except Exception:
pass
self._stream = None