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Open-source wake word detection SDK with training pipeline — privacy-first, on-device, Python-native

Project description

ViolaWake SDK

The open-source alternative to Porcupine. A production-tested wake word engine with accessible training, ONNX inference, and a Python-first SDK.

PyPI version CI License: Apache 2.0 Python 3.10+


Why ViolaWake?

ViolaWake Porcupine (Picovoice) openWakeWord
License Apache 2.0 Proprietary (metered) Apache 2.0
Training code open Yes No (closed) Yes
Custom wake words Yes (training CLI) Yes (paid Console) Yes (fine-tune)
Evaluation tooling violawake-eval (Cohen's d, EER, FAR/FRR, ROC AUC) None published Basic
On-device Yes (ONNX) Yes (proprietary C lib) Yes (ONNX)
Integrated TTS Yes (Kokoro-82M, optional extra) No No
Speaker verification Yes (post-detection gate) No No
Noise-adaptive threshold Yes (SNR-based) No No
Power management Yes (duty cycling, battery-aware) No No
Audio source abstraction Yes (mic, file, network, callback) No No
Python SDK First-class C wrapper First-class
Price at scale Free Paid (free tier available) Free

Our moat: Open training code, transparent evaluation with reproducible benchmarks, production-hardened data augmentation (gain, time stretch, pitch shift, noise mixing), and a 4-gate decision policy that suppresses false positives during music playback. On a fair head-to-head benchmark against openWakeWord (same corpus, same pipeline, adversarial negatives for both systems), ViolaWake achieves EER 5.49% vs OWW's 8.24% — each system tested on its own best wake word. Running in production, not a demo.

A note on accuracy claims: Our benchmark uses TTS-generated audio with adversarial confusables, not real-speaker recordings. Real-world accuracy depends on your deployment environment. We publish our benchmark scripts so you can reproduce and extend them. Run violawake-eval on your own test data.


Quick Start

pip install "violawake[audio,download]"
violawake-download --model temporal_cnn

Wake Word Detection (5 lines)

from violawake_sdk import WakeDetector

detector = WakeDetector(model="temporal_cnn", threshold=0.80, confirm_count=3)

for audio_chunk in detector.stream_mic():  # 20ms chunks at 16kHz
    if detector.detect(audio_chunk):
        print("Wake word detected!")
        break

confirm_count=3 requires 3 consecutive above-threshold frames before firing, significantly reducing false accepts. Use confirm_count=1 for lowest latency.

All major classes support context managers for automatic cleanup:

with WakeDetector(model="temporal_cnn", threshold=0.80) as detector:
    for chunk in detector.stream_mic():
        if detector.detect(chunk):
            print("Detected!")
            break
# Resources automatically released on exit

Threshold Tuning

The threshold parameter controls the trade-off between sensitivity and false positives:

Threshold Behavior Use Case
0.70 Sensitive -- more detections, more false positives Quiet rooms, close-mic setups
0.80 Balanced (default) -- recommended starting point General-purpose, most environments
0.85 Conservative -- fewer false positives, may miss some wake words Living rooms with TV/music
0.90+ Very conservative -- lowest false positive rate Noisy environments, always-on kiosks

Start at 0.80 and adjust based on your false accept rate. Use violawake-streaming-eval to measure FAPH (false accepts per hour) on representative audio from your deployment environment, or violawake-eval for clip-by-clip EER/FAR/FRR/ROC AUC.

Text-to-Speech (Kokoro-82M)

from violawake_sdk import TTSEngine

with TTSEngine() as tts:  # Downloads models on first run (~354MB total)
    audio = tts.synthesize("Hello from ViolaWake!")
    tts.play(audio)

Voice Activity Detection

from violawake_sdk import VADEngine

with VADEngine(backend="webrtc") as vad:  # or "silero", "rms"
    prob = vad.process_frame(audio_bytes)  # returns 0.0-1.0 speech probability

Three VAD backends are available:

Backend Engine Latency Accuracy Dependencies
webrtc WebRTC VAD <1ms Good webrtcvad
silero Silero VAD ~2ms Best torch or onnxruntime
rms RMS heuristic <0.1ms Basic None (built-in)
auto Best available Varies Varies Tries webrtc -> silero -> rms

Full Pipeline (Wake -> STT -> TTS)

Requires: pip install "violawake[audio,stt,tts]"

from violawake_sdk import VoicePipeline

pipeline = VoicePipeline(
    wake_word="viola",
    stt_model="base",        # faster-whisper model size
    tts_voice="af_heart",    # Kokoro voice
)

@pipeline.on_command
def handle_command(text: str) -> str:
    print(f"Command: {text}")
    return f"You said: {text}"  # Returned string is spoken via TTS

pipeline.run()  # Blocks -- Ctrl+C to stop

The pipeline follows a 4-state machine: IDLE -> LISTENING -> TRANSCRIBING -> RESPONDING -> IDLE. State transitions happen automatically based on wake word detection, VAD silence detection, and TTS completion.


Audio Sources

ViolaWake defines an AudioSource protocol for pluggable audio input. Four implementations are included:

MicrophoneSource (default)

from violawake_sdk.audio_source import MicrophoneSource

source = MicrophoneSource(device_index=None)  # None = system default
source.start()
while True:
    frame = source.read_frame()  # 640 bytes (20ms at 16kHz, int16)
    if frame and detector.detect(frame):
        print("Detected!")
source.stop()

FileSource (for testing and evaluation)

from violawake_sdk.audio_source import FileSource

source = FileSource("test_audio.wav", loop=False)
source.start()
while (frame := source.read_frame()) is not None:
    if detector.detect(frame):
        print("Detected!")
source.stop()

Reads WAV files natively. FLAC/MP3 supported if soundfile is installed. Auto-warns on sample rate or channel mismatch (expects 16kHz mono int16).

NetworkSource (for distributed systems)

from violawake_sdk.audio_source import NetworkSource

# TCP streaming from a remote microphone
source = NetworkSource(host="0.0.0.0", port=9999, protocol="tcp")
source.start()  # Binds and accepts first connection
frame = source.read_frame()

# UDP streaming
source = NetworkSource(port=9999, protocol="udp", timeout=5.0)

Security note: NetworkSource provides no authentication or encryption. Use only on trusted networks.

CallbackSource (push model)

from violawake_sdk.audio_source import CallbackSource

source = CallbackSource(timeout=1.0, max_queue_size=100)
source.start()

# Push audio from any thread (accepts bytes or numpy arrays)
source.push_audio(audio_bytes)
source.push_audio(numpy_float32_array)  # Auto-converts float32 -> int16

frame = source.read_frame()  # Blocks until data arrives or timeout

Ideal for integration with existing audio pipelines, WebSocket servers, or callback-based audio APIs. Drops oldest frames on queue overflow.

Custom AudioSource

Implement the protocol for your own audio source:

from violawake_sdk.audio_source import AudioSource

class MySource:
    def read_frame(self) -> bytes | None:
        """Return 640 bytes (320 int16 samples) or None if exhausted."""
        ...
    def start(self) -> None: ...
    def stop(self) -> None: ...

assert isinstance(MySource(), AudioSource)  # Runtime-checkable protocol

Async Detection

For asyncio-based applications, use AsyncWakeDetector:

from violawake_sdk import AsyncWakeDetector

async with AsyncWakeDetector(model="temporal_cnn", threshold=0.80) as detector:
    result = await detector.detect(audio_frame)

    # Or stream from an async audio source
    async for detected in detector.stream(audio_source):
        if detected:
            print("Wake word!")

AsyncWakeDetector wraps WakeDetector in a ThreadPoolExecutor(max_workers=1) to avoid blocking the event loop during ONNX inference. All constructor parameters are forwarded to WakeDetector.


Speaker Verification

Restrict wake word activation to enrolled speakers using post-detection speaker verification:

from violawake_sdk.speaker import SpeakerVerificationHook, SpeakerProfile

# Create a verification hook
hook = SpeakerVerificationHook(threshold=0.65)

# Enroll a speaker (requires OWW backbone embeddings)
# Collect embeddings during a dedicated enrollment session
hook.enroll_speaker("alice", enrollment_embeddings)  # list of np.ndarray

# Wire into the detector
detector = WakeDetector(
    model="temporal_cnn",
    threshold=0.80,
    speaker_verify_fn=hook,  # Called after each detection
)

# Detection now requires both wake word match AND speaker match
for chunk in detector.stream_mic():
    if detector.detect(chunk):
        print("Wake word detected by enrolled speaker!")

Persistence

# Save enrolled speakers
hook.save("speakers.json")  # JSON metadata + .npz embeddings (no pickle)

# Load later
hook.load("speakers.json")

Speaker Management

hook.enroll_speaker("bob", embeddings)   # Returns enrollment count
hook.remove_speaker("bob")               # Returns True if found

# Verify a single embedding
result = hook.verify_speaker(embedding)
print(result.is_verified, result.speaker_id, result.similarity)

Thread-safe. Capped at 1000 embeddings per speaker for DoS protection on deserialization.


Noise-Adaptive Detection

Automatically adjust the detection threshold based on ambient noise levels:

from violawake_sdk import WakeDetector
from violawake_sdk.noise_profiler import NoiseProfiler

profiler = NoiseProfiler(
    base_threshold=0.80,
    noise_window_s=5.0,     # Rolling window for noise estimation
    min_threshold=0.60,      # Floor (never go below)
    max_threshold=0.95,      # Ceiling (never go above)
    snr_boost_db=6.0,        # High SNR -> lower threshold (easier detection)
    snr_penalty_db=3.0,      # Low SNR -> raise threshold (fewer false positives)
)

detector = WakeDetector(
    model="temporal_cnn",
    adaptive_threshold=True,
    noise_profiler=profiler,
)

The profiler estimates the noise floor as the 10th percentile of recent RMS values, then adjusts the threshold by up to +/-0.10 based on signal-to-noise ratio. In quiet rooms, the threshold drops for better sensitivity; in noisy environments, it rises to reduce false accepts.

# Inspect the current noise profile
profile = profiler.get_profile()
print(f"Noise: {profile.noise_rms:.1f}, SNR: {profile.snr_db:.1f} dB, "
      f"Threshold: {profile.adjusted_threshold:.2f}")

Power Management

Reduce CPU usage on battery-powered devices with intelligent frame skipping:

from violawake_sdk import WakeDetector
from violawake_sdk.power_manager import PowerManager

pm = PowerManager(
    duty_cycle_n=1,          # Process every Nth frame when idle (1 = all)
    silence_rms=10.0,        # Skip inference below this RMS
    activity_threshold=0.3,  # Score above this triggers full-rate mode
    active_window_s=3.0,     # Stay in full-rate mode for 3s after activity
    battery_low_pct=20,      # Battery % below which power saving kicks in
    battery_multiplier=3,    # Multiply duty cycle by 3x on low battery
)

detector = WakeDetector(
    model="temporal_cnn",
    power_manager=pm,
)

Three power-saving strategies work together:

  1. Duty cycling -- process every Nth frame when idle
  2. Silence skipping -- skip inference entirely when input RMS is below threshold
  3. Battery-aware -- multiplies duty cycle when on battery + low charge

Battery detection is cross-platform: tries psutil, falls back to Windows ctypes or Linux /sys/class/power_supply/.

# Monitor power state
state = pm.get_state()
print(f"Battery: {state.battery_percent}%, Processed: {state.frames_processed}, "
      f"Skipped: {state.frames_skipped}, Rate: {state.effective_rate:.0%}")

Multi-Model Ensemble

Run multiple models simultaneously and fuse their scores for higher accuracy:

from violawake_sdk import WakeDetector, FusionStrategy

detector = WakeDetector(
    model="temporal_cnn",
    models=["temporal_cnn", "temporal_convgru"],
    fusion_strategy=FusionStrategy.AVERAGE,  # or MAX, VOTING, WEIGHTED_AVERAGE
    fusion_weights=[0.7, 0.3],  # For WEIGHTED_AVERAGE
)
Strategy Behavior Best For
AVERAGE Mean of all model scores General purpose
MAX Highest score wins Maximizing recall
VOTING Fraction of models above threshold Reducing false positives
WEIGHTED_AVERAGE Weighted mean (requires fusion_weights) Tuned deployments
# Access individual model scores
from violawake_sdk.ensemble import EnsembleScorer
scores = detector._ensemble.score_all(embedding)  # list[float] per model

Confidence API

Track detection confidence beyond a simple boolean:

from violawake_sdk import WakeDetector, ConfidenceResult, ConfidenceLevel

detector = WakeDetector(model="temporal_cnn", threshold=0.80, score_history_size=50)

# After processing frames...
result: ConfidenceResult = detector.get_confidence()
print(f"Score: {result.raw_score:.3f}")
print(f"Level: {result.confidence}")          # LOW, MEDIUM, HIGH, or CERTAIN
print(f"Confirm: {result.confirm_count}/{result.confirm_required}")
print(f"History: {result.score_history[-5:]}")  # Last 5 scores

# Access raw score history
scores = detector.last_scores  # tuple[float, ...]

Confidence levels are classified relative to the threshold:

  • LOW -- below 75% of threshold
  • MEDIUM -- 75-90% of threshold
  • HIGH -- 90-100% of threshold
  • CERTAIN -- above threshold with confirmation met

Advanced Configuration

DetectorConfig bundles all advanced options into a single object:

from violawake_sdk import DetectorConfig, WakeDetector, FusionStrategy
from violawake_sdk.noise_profiler import NoiseProfiler
from violawake_sdk.power_manager import PowerManager
from violawake_sdk.speaker import SpeakerVerificationHook

config = DetectorConfig(
    # Multi-model ensemble
    models=["temporal_cnn", "temporal_convgru"],
    fusion_strategy=FusionStrategy.AVERAGE,
    fusion_weights=None,

    # Noise-adaptive threshold
    adaptive_threshold=True,
    noise_profiler=NoiseProfiler(base_threshold=0.80),

    # Speaker verification (post-detection gate)
    speaker_verify_fn=SpeakerVerificationHook(threshold=0.65),

    # Power management
    power_manager=PowerManager(duty_cycle_n=2),

    # Confidence tracking
    confirm_count=3,
    score_history_size=50,
)

detector = config.build(model="temporal_cnn", threshold=0.80, cooldown_s=2.0)

Or pass options directly to the constructor:

detector = WakeDetector(
    model="temporal_cnn",
    threshold=0.80,
    cooldown_s=2.0,
    backend="onnx",           # "onnx", "tflite", or "auto"
    providers=["CPUExecutionProvider"],  # ONNX Runtime execution providers
    confirm_count=3,
    adaptive_threshold=True,
    noise_profiler=NoiseProfiler(),
    power_manager=PowerManager(),
    speaker_verify_fn=hook,
    models=["temporal_cnn", "temporal_convgru"],
    fusion_strategy="average",
    score_history_size=50,
)

Architecture

┌─────────────────────────────────────────────────────────────┐
│                    VoicePipeline                            │
│                                                             │
│  AudioSource ──► [WakeDetector] ──► [VAD] ──► [STT] ──► cb│
│                                                             │
│  text ──► [TTS] ──► Speaker                                │
└─────────────────────────────────────────────────────────────┘

Components:

Module Engine Size Latency
Wake word Temporal CNN on OWW embeddings (ONNX) ~100 KB head (+OWW backbone via openwakeword) ~8ms/frame
VAD WebRTC VAD / Silero / RMS heuristic <1 MB <1ms/frame
STT faster-whisper base 145 MB 0.5-2s
TTS Kokoro-82M (ONNX) 326 MB 0.3-0.8s/sentence

Inference Backends

Two inference backends are supported:

Backend Runtime Status
onnx ONNX Runtime Default -- CPU/GPU via execution providers
tflite TensorFlow Lite Alternative for embedded/mobile targets
auto Best available Tries ONNX first, falls back to TFLite
from violawake_sdk.backends import get_backend

backend = get_backend("onnx", providers=["CUDAExecutionProvider", "CPUExecutionProvider"])
print(backend.is_available())

Training Your Own Wake Word

The training CLI lets you train a custom wake word model with ~200 positive samples:

# Collect positive samples (read prompts aloud)
violawake-collect --word "jarvis" --output data/jarvis/positives/ --count 200

# Train (auto-generates TTS positives, confusable negatives, and speech negatives)
violawake-train \
  --word "jarvis" \
  --positives data/jarvis/positives/ \
  --output models/jarvis.onnx \
  --epochs 50

# To disable augmentation, add --no-augment
# To use legacy MLP architecture, add --architecture mlp

# Evaluate (EER, FAR/FRR, ROC AUC)
violawake-eval \
  --model models/jarvis.onnx \
  --test-dir data/jarvis/test/ \
  --report

The --test-dir must contain positives/ and negatives/ subdirectories.

Expected results: EER < 10% (against the bundled synthetic negative corpus) with 200+ quality positive samples. Your real-world performance will depend on your deployment environment and negative speech corpus.

Training Infrastructure

The training pipeline uses production techniques for class-imbalanced wake word detection:

  • FocalLoss (gamma=2.0, alpha=0.75) -- down-weights easy negatives, focuses on hard examples
  • Label smoothing (0.05) -- prevents overconfident predictions
  • EMA (exponential moving average, decay=0.999) -- smooths weight updates
  • SWA (stochastic weight averaging) -- averages weights across epochs for better generalization
  • AdamW with cosine annealing learning rate schedule
  • Early stopping on validation loss
  • 80/20 group-aware train/val split -- ensures same speaker's samples stay together

Data Augmentation

Seven augmentation types are applied during training (configurable probabilities):

Augmentation Default Probability Range
Gain 80% -6 to +6 dB
Time stretch 50% 0.9x - 1.1x speed
Pitch shift 50% +/-2 semitones
Additive noise 70% 5-20 dB SNR
Time shift 50% +/-10% of clip length
RIR convolution 0% (opt-in) Room impulse responses
SpecAugment 0% (opt-in) Frequency/time masking on spectrograms

Auto-Generated Training Data

When you run violawake-train, the CLI automatically generates:

  • TTS positives -- 20 Edge TTS voices x 3 phrase variants (e.g., "jarvis", "hey jarvis", "ok jarvis") x 3 augmentation conditions
  • Confusable negatives -- 16+ phonetic variants of the wake word generated via phonetic substitution tables (b/p, d/t, f/v, g/j, etc.)
  • Speech negatives -- common English phrases that are not the wake word

Proof: "Operator" Custom Wake Word (89 seconds, EER 7.2%)

To prove the training pipeline generalizes beyond "Viola," we trained a custom "operator" model from scratch -- zero manual data collection:

ViolaWake "viola" ViolaWake "operator" OWW "alexa" (pre-trained)
EER 5.49% 7.2% 8.24%
ROC AUC 0.988 0.984 0.956
Training time ~48s 89s N/A (pre-trained)
Architecture Temporal CNN Temporal CNN MLP on OWW embeddings

The training CLI handled TTS sample generation (20 Edge TTS voices), confusable negative generation (16 phonetic variants), 10x augmentation, and Temporal CNN training end-to-end. OWW provides training notebooks but no pip-installable CLI tool.

Full methodology, corpus details, and reproducibility instructions: benchmark_v2/OPERATOR_BENCHMARK.md


CLI Tools Reference

ViolaWake ships 9 CLI tools, all available after pip install "violawake[all]":

Core Tools

Command Purpose
violawake-download Download models from the registry
violawake-train Train a custom wake word model
violawake-eval Evaluate a model (EER, FAR/FRR, ROC AUC, Cohen's d)
violawake-collect Record positive samples from microphone

Evaluation & Testing

Command Purpose
violawake-streaming-eval Measure FAPH (false accepts per hour) on continuous audio
violawake-test-confusables Test a model against phonetically similar words
violawake-contamination-check Detect train/eval data overlap (filename, hash, embedding similarity)

Data & Corpus

Command Purpose
violawake-generate Generate TTS positive samples and confusable negatives
violawake-expand-corpus Download standard evaluation corpora (LibriSpeech, MUSAN)

Usage Examples

# Download a model
violawake-download --model temporal_cnn

# Generate training data without recording
violawake-generate --word "jarvis" --output data/jarvis/ \
  --count 200 --voices 20 --negatives --neg-count 300

# Streaming FAPH evaluation on a WAV file
violawake-streaming-eval --model models/jarvis.onnx --audio test_audio.wav

# Check for train/eval contamination
violawake-contamination-check \
  --train-dir data/jarvis/train/ \
  --eval-dir data/jarvis/test/ \
  --cosine-threshold 0.99

# Download evaluation corpora
violawake-expand-corpus --corpus librispeech-test-clean --output data/corpora/

# Test against phonetic confusables
violawake-test-confusables --model models/jarvis.onnx --word "jarvis"

Models

Models are versioned and published to GitHub Releases. Use registry names without file extensions when passing --model or WakeDetector(model=...). Download separately (too large for PyPI):

violawake-download --model temporal_cnn           # default, ~100 KB
violawake-download --model kokoro_v1_0             # TTS model, 326 MB
violawake-download --model kokoro_voices_v1_0      # TTS voices, 28 MB
Model Type Size EER* Notes
temporal_cnn.onnx Temporal CNN on OWW embeddings ~100 KB 5.49% Production default -- best live recall + lowest FP
temporal_convgru.onnx Temporal Conv-GRU on OWW embeddings ~81 KB -- Reserve model
r3_10x_s42.onnx MLP on OWW embeddings ~34 KB -- Deprecated -- fails live mic test. Do not use.
kokoro-v1.0.onnx Kokoro-82M TTS ~326 MB -- Apache 2.0 (hosted by kokoro-onnx)

*EER (Equal Error Rate) from benchmark v2: 700 shared negatives (incl. adversarial confusables), 180 TTS positives, streaming inference. Lower is better. See benchmark_v2/ for full methodology and scripts.

Model Discovery

from violawake_sdk import list_models, list_voices

# List available wake word models
for m in list_models():
    print(f"{m['name']:20s} {m['description']}")

# List available TTS voices
voices = list_voices()  # ['af_heart', 'af_bella', 'af_sarah', ...]

Model Integrity

Downloads are verified via SHA-256 hash comparison against the model registry. The OpenWakeWord backbone files (mel-spectrogram + embedding models) are additionally verified at load time -- a hash mismatch produces a warning suggesting retraining, since backbone drift can silently degrade accuracy.


Security

Download Security

  • All model downloads enforce HTTPS-only URLs
  • SHA-256 integrity checks on every download
  • Atomic writes prevent partial/corrupt model files
  • Size validation (within 5% of declared size)

Certificate Pinning

Optional TLS certificate pinning for model downloads:

from violawake_sdk.models import download_model

# Download with certificate pinning enabled
path = download_model("temporal_cnn", use_pinning=True, strict=False)

The pinning system uses SPKI (Subject Public Key Info) SHA-256 hashes with TOFU (Trust On First Use) for GitHub and HuggingFace domains.

OWW Backbone Integrity

The OpenWakeWord mel-spectrogram and embedding models are pinned by SHA-256 hash at training time and verified at inference time. If the hash changes (e.g., openwakeword package updated), a warning is logged:

WARNING: OWW backbone hash mismatch. Re-train your model if detection accuracy degrades.

Safe Deserialization

Speaker verification profiles use JSON + .npz for persistence -- no pickle. Embedding counts are capped at 1000 per speaker to prevent DoS via crafted profile files.


Environment Variables

Variable Default Description
VIOLAWAKE_MODEL_DIR ~/.violawake/models/ Directory for downloaded models
VIOLAWAKE_NO_AUTO_DOWNLOAD unset Set to 1, true, or yes to disable automatic model downloads (raises FileNotFoundError instead)
# Custom model directory
export VIOLAWAKE_MODEL_DIR=/opt/violawake/models

# Air-gapped deployment (pre-download models, disable auto-download)
export VIOLAWAKE_NO_AUTO_DOWNLOAD=1

Thread Safety

All core classes are thread-safe:

  • WakeDetector -- two-lock design (_lock for scores, _backbone_lock for OWW state) with documented lock ordering to prevent deadlocks
  • SpeakerVerificationHook -- lock-guarded profile mutations, snapshot-based reads
  • PowerManager -- lock-guarded frame counters and battery state
  • VoicePipeline -- state machine transitions and worker management under locks
  • CallbackSource -- thread-safe queue with push_audio() from any thread

Safe to share a WakeDetector across threads. For asyncio, use AsyncWakeDetector instead.


Platform Support

Platform Wake Word TTS STT Status
Windows 10/11 (x64) Fully tested
Linux (x64) CI-tested
macOS (arm64/x64) CI-tested (Intel), community (ARM)
Raspberry Pi 4 (ARM64) ⚠️ slow Supported
Browser/WASM 🚧 🚧 Phase 2 (Q3 2026)
Android Phase 3 (2027)
iOS Phase 3 (2027)

Installation

Minimum install (wake word + VAD only):

pip install violawake

Note: Both import violawake and import violawake_sdk work. The canonical import is violawake_sdk (e.g., from violawake_sdk import WakeDetector), but from violawake import WakeDetector is also supported for convenience.

With microphone input and model downloading:

pip install "violawake[audio,download]"

With TTS:

pip install "violawake[tts]"

With STT:

pip install "violawake[stt]"

Full pipeline (all features):

pip install "violawake[all]"

Requirements:

  • Python 3.10+
  • onnxruntime >= 1.17 (CPU) or onnxruntime-gpu for GPU acceleration
  • pyaudio for microphone input
  • numpy, scipy
  • openwakeword >= 0.6 (optional [oww] extra -- provides the frozen mel/embedding backbone)

Performance Benchmarks

Measured on i7-12700H, Windows 11, RTX 3060 (CPU inference):

Operation Latency (p50) Latency (p99)
Wake word inference (20ms frame) 7.8 ms 12.1 ms
VAD (WebRTC, 20ms frame) 0.4 ms 0.8 ms
STT (Whisper base, 3s audio) 680 ms 1.2s
TTS first audio (Kokoro, 1 sentence) 310 ms 580 ms

Wake word accuracy (benchmark v2 -- TTS corpus, 700 negatives incl. adversarial confusables):

  • Temporal CNN model: EER 5.49%, ROC AUC 0.9877
  • FAR @ FRR=5%: 5.43% (vs OWW's 8.86% on its own best word)
  • Live mic tested: 100% recall on direct speech, 0 false positives on podcast/music
  • Real-world metrics depend on your deployment environment. Run violawake-eval (clip-by-clip) or violawake-streaming-eval (continuous FAPH) on your own test data.

Debugging

Enable debug logging to see gate rejections, backbone output, score tracking, and detection decisions:

import logging
logging.basicConfig(level=logging.DEBUG)

from violawake_sdk import WakeDetector
detector = WakeDetector(model="temporal_cnn", threshold=0.80)

This produces output like:

  • Gate 1 reject: RMS 0.0 below floor 1.0 -- silence/DC offset filtered
  • Gate 3 reject: cooldown active (1.2s remaining) -- too soon after last detection
  • Gate 4 reject: playback active -- suppressed during music
  • Wake word detected! score=0.872 -- successful detection

Set level=logging.INFO for detections only (less verbose).


Examples

The examples/ directory contains runnable scripts:

File Description
examples/basic_detection.py Minimal microphone wake word detection loop
examples/async_detection.py Async wake word detection with AsyncWakeDetector
examples/streaming_eval.py Evaluate false accepts per hour on a WAV file

Run any example with:

python examples/basic_detection.py

Comparison to openWakeWord

openWakeWord is the closest open-source alternative. ViolaWake differences:

  • Open, reproducible evaluation: violawake-eval produces EER, FAR/FRR, ROC AUC on any model + test set. violawake-streaming-eval measures FAPH on continuous audio. Benchmark scripts in benchmark_v2/ -- run them yourself.
  • Production-hardened decision policy: 4-gate pipeline (zero-input guard, score threshold, cooldown, listening gate) plus optional multi-window confirmation -- suppresses false positives during music playback when is_playing state is wired up
  • Bundled pipeline: ViolaWake ships integrated VAD + STT + TTS, not just the wake word component
  • Training infrastructure: FocalLoss + EMA + SWA + augmentation pipeline (gain, stretch, pitch, noise, time shift; RIR and SpecAugment available opt-in) vs basic training in openWakeWord
  • Speaker verification: Post-detection speaker gate with enrollment/persistence -- OWW has no speaker verification
  • Noise-adaptive threshold: SNR-based threshold adjustment -- OWW uses static thresholds
  • Power management: Duty cycling + silence skipping + battery-awareness -- OWW has no power management
  • Audio source abstraction: Pluggable mic/file/network/callback sources -- OWW requires manual audio handling

Migrating from openWakeWord

ViolaWake uses openWakeWord's mel-spectrogram embedding model as a frozen feature extractor backbone. If you have existing OWW training data, you can use it directly with ViolaWake's training CLI.

Key differences from OWW:

  • Decision policy: ViolaWake adds a multi-gate pipeline (RMS floor, cooldown, playback suppression) on top of raw scores. OWW exposes raw sigmoid scores only.
  • Temporal models: ViolaWake supports Temporal CNN and Conv-GRU heads that score across a sliding window of embeddings, not just a single frame. This reduces false positives on speech that partially matches the wake word.
  • Augmentation pipeline: ViolaWake's training CLI applies gain, time stretch, pitch shift, noise mixing, and RIR convolution. SpecAugment is available for custom spectrogram-level pipelines via AugmentationPipeline.augment_spectrogram(). OWW's default training uses minimal augmentation.
  • Confidence API: detector.get_confidence() and detector.last_scores provide structured confidence tracking that OWW does not offer.

Using existing OWW training data:

# Your OWW positive samples work as-is (16kHz WAV/FLAC)
violawake-train \
  --word "my_wake_word" \
  --positives path/to/oww_positives/ \
  --negatives path/to/oww_negatives/ \
  --output models/my_wake_word.onnx \
  --epochs 50

No format conversion is needed -- ViolaWake reads the same 16kHz mono WAV/FLAC files that OWW uses.


API Reference

Public Exports (from violawake_sdk import ...)

Core Detection:

  • WakeDetector -- synchronous wake word detector
  • AsyncWakeDetector -- async wrapper for asyncio
  • DetectorConfig -- bundled advanced configuration
  • WakeDecisionPolicy -- 4-gate decision pipeline
  • validate_audio_chunk -- input validation utility

Confidence & Scoring:

  • ConfidenceResult -- structured confidence snapshot
  • ConfidenceLevel -- LOW/MEDIUM/HIGH/CERTAIN enum
  • FusionStrategy -- ensemble fusion strategy enum

Pipeline Components:

  • VoicePipeline -- full Wake -> VAD -> STT -> TTS orchestration
  • VADEngine -- voice activity detection (3 backends)
  • TTSEngine -- Kokoro-82M text-to-speech (optional [tts] extra)
  • STTEngine -- faster-whisper speech-to-text (optional [stt] extra)

Audio Sources (from violawake_sdk.audio_source import ...):

  • AudioSource -- runtime-checkable protocol
  • MicrophoneSource -- PyAudio microphone capture
  • FileSource -- WAV/FLAC file playback
  • NetworkSource -- TCP/UDP raw PCM streaming
  • CallbackSource -- push-model audio ingestion

Advanced (from violawake_sdk.<module> import ...):

  • NoiseProfiler, NoiseProfile -- noise-adaptive threshold (noise_profiler)
  • PowerManager, PowerState -- battery-aware power management (power_manager)
  • SpeakerVerificationHook, SpeakerProfile, SpeakerVerifyResult -- speaker verification (speaker)
  • EnsembleScorer -- multi-model scoring (ensemble)
  • ScoreTracker -- score history tracking (confidence)

Exceptions:

  • ViolaWakeError -- base exception
  • ModelNotFoundError -- model not in registry or on disk
  • ModelLoadError -- model file corrupt or incompatible
  • AudioCaptureError -- microphone/audio source failure
  • PipelineError -- voice pipeline state error

Discovery:

  • list_models() -- available wake word models
  • list_voices() -- available TTS voices
  • __version__ -- SDK version string

Roadmap

v1.0 (Q2 2026) -- Phase 1 MVP:

  • Python SDK (Wake + VAD)
  • Kokoro TTS integration
  • faster-whisper STT integration
  • Full VoicePipeline class
  • Training CLI (9 tools)
  • PyPI release
  • Speaker verification
  • Noise-adaptive detection
  • Power management
  • Audio source abstraction
  • Multi-model ensemble
  • Documentation site

v1.1 (Q3 2026) -- Streaming + Web:

  • Streaming STT (faster-whisper generator mode)
  • WASM build for ViolaWake
  • JavaScript/Node SDK wrapper
  • Custom wake word web Console (alpha)

v2.0 (Q1 2027) -- Multi-platform:

  • Android SDK (ONNX Runtime Android)
  • iOS SDK (ONNX Runtime iOS)
  • DeepFilterNet noise suppression integration
  • Speaker diarization (pyannote.audio)
  • License/metering infrastructure

Contributing

git clone https://github.com/GeeIHadAGoodTime/ViolaWake
cd ViolaWake
pip install -e ".[dev]"
pre-commit install
pytest tests/

See CONTRIBUTING.md for guidelines.


License

Apache 2.0. Models trained on open datasets. See LICENSE for details.

ViolaWake uses OpenWakeWord as a frozen feature extractor backbone (also Apache 2.0). The classification heads (Temporal CNN, Conv-GRU) and training pipeline are original ViolaWake work.

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