wakeword / app.py
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Replace Wav2Vec2 with DSCNN model for keyword spotting
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import gradio as gr
import numpy as np
import librosa
import tensorflow as tf
from scipy.fftpack import dct
import os
# DSCNN model configuration
MODEL_PATH = "ds_cnn_l_quantized.tflite"
# Keywords based on Speech Commands dataset (12 classes)
KEYWORDS = [
"silence", "unknown", "yes", "no", "up", "down",
"left", "right", "on", "off", "stop", "go"
]
print("Loading DSCNN TensorFlow Lite model...")
try:
# Load the TFLite model
interpreter = tf.lite.Interpreter(model_path=MODEL_PATH)
interpreter.allocate_tensors()
# Get input and output details
input_details = interpreter.get_input_details()
output_details = interpreter.get_output_details()
print(f"βœ… DSCNN model loaded successfully!")
print(f"Input shape: {input_details[0]['shape']}")
print(f"Output shape: {output_details[0]['shape']}")
print(f"Input dtype: {input_details[0]['dtype']}")
print(f"Output dtype: {output_details[0]['dtype']}")
except Exception as e:
print(f"❌ Error loading DSCNN model: {e}")
interpreter = None
def extract_mfcc_features(audio_path, target_length=490):
"""
Extract MFCC features exactly as specified in the original DSCNN paper.
Based on "Hello Edge: Keyword Spotting on Microcontrollers"
Parameters from paper:
- 40ms frame length (640 samples at 16kHz)
- 20ms stride (320 samples at 16kHz)
- 10 MFCC features per frame
- 49 frames total for 1 second β†’ 49Γ—10 = 490 features
"""
try:
# Load audio and resample to 16kHz (standard for speech commands)
audio, sr = librosa.load(audio_path, sr=16000, mono=True)
# Ensure audio is exactly 1 second (16000 samples)
if len(audio) < 16000:
# Pad with zeros
audio = np.pad(audio, (0, 16000 - len(audio)), 'constant')
else:
# Truncate to 1 second
audio = audio[:16000]
# DSCNN paper parameters
frame_length = 640 # 40ms at 16kHz
hop_length = 320 # 20ms at 16kHz (50% overlap)
n_mfcc = 10 # 10 MFCC features as in paper
n_fft = 1024 # FFT size
n_mels = 40 # Mel filter bank size (before DCT)
# Extract mel spectrogram
mel_spec = librosa.feature.melspectrogram(
y=audio,
sr=sr,
n_fft=n_fft,
hop_length=hop_length,
win_length=frame_length,
n_mels=n_mels,
fmin=20,
fmax=4000
)
# Convert to log scale
log_mel_spec = librosa.power_to_db(mel_spec, ref=np.max)
# Apply DCT to get MFCC features (only take first 10 coefficients)
mfcc_features = dct(log_mel_spec, axis=0, norm='ortho')[:n_mfcc, :]
# Should be shape (10, 49) for 1 second of audio
print(f"MFCC shape before flattening: {mfcc_features.shape}")
# Flatten to 1D array (10 Γ— 49 = 490 features)
features_flat = mfcc_features.flatten()
# Ensure exactly 490 features
if len(features_flat) > target_length:
features_flat = features_flat[:target_length]
elif len(features_flat) < target_length:
features_flat = np.pad(features_flat, (0, target_length - len(features_flat)), 'constant')
print(f"Features length after processing: {len(features_flat)}")
# Normalize features (zero mean, unit variance)
features_flat = (features_flat - np.mean(features_flat)) / (np.std(features_flat) + 1e-8)
# Quantize to INT8 range for DSCNN model
# Scale to approximately match training distribution
features_int8 = np.clip(features_flat * 127.0, -128, 127).astype(np.int8)
return features_int8.reshape(1, -1) # Shape: (1, 490)
except Exception as e:
raise Exception(f"Error extracting MFCC features: {str(e)}")
def classify_audio(audio_input):
"""
Classify the input audio using the DSCNN model and return keyword predictions.
"""
if audio_input is None:
return "Please upload an audio file or record audio."
if interpreter is None:
return "❌ DSCNN model not loaded. Please refresh the page and try again."
try:
# Extract MFCC features
features = extract_mfcc_features(audio_input)
print(f"Input features shape: {features.shape}")
print(f"Input features dtype: {features.dtype}")
print(f"Input features range: [{features.min()}, {features.max()}]")
# Set input tensor
interpreter.set_tensor(input_details[0]['index'], features)
# Run inference
interpreter.invoke()
# Get output
output_data = interpreter.get_tensor(output_details[0]['index'])
print(f"Raw output shape: {output_data.shape}")
print(f"Raw output dtype: {output_data.dtype}")
print(f"Raw output range: [{output_data.min()}, {output_data.max()}]")
# Handle quantized INT8 output
if output_data.dtype == np.int8:
# Dequantize INT8 to float (assuming symmetric quantization)
# Scale factor is typically around 1/128 for INT8
logits = output_data.astype(np.float32) / 128.0
else:
logits = output_data.astype(np.float32)
# Apply softmax to get probabilities
exp_logits = np.exp(logits - np.max(logits))
probabilities = exp_logits / np.sum(exp_logits)
# Get predictions with confidence scores
predictions = []
for i, prob in enumerate(probabilities[0]):
predictions.append({
'label': KEYWORDS[i],
'score': float(prob)
})
# Sort by confidence score
predictions = sorted(predictions, key=lambda x: x['score'], reverse=True)
# Format results
results = []
for i, pred in enumerate(predictions[:5]):
confidence = pred['score'] * 100
label = pred['label']
indicator = "🎯" if i == 0 else " "
results.append(f"{indicator} {i+1}. {label}: {confidence:.1f}%")
return "\n".join(results)
except Exception as e:
error_msg = str(e)
if "mfcc" in error_msg.lower() or "librosa" in error_msg.lower():
return "❌ Audio processing error. Please ensure your audio file is in a supported format (WAV, MP3, etc.)"
elif "model" in error_msg.lower() or "tensor" in error_msg.lower():
return "❌ Model inference error. Please try recording a clear 1-second audio clip."
else:
return f"❌ Error processing audio: {error_msg}\n\nTip: Try recording a clear 1-second word like 'yes' or 'stop'."
# Create the Gradio interface
demo = gr.Interface(
fn=classify_audio,
inputs=gr.Audio(sources=["microphone", "upload"], type="filepath", label="Record or Upload Audio"),
outputs=gr.Textbox(label="DSCNN Keyword Predictions", lines=8),
title="🎀 DSCNN Wake Word Detection Demo",
description="""
**Advanced wake word detection using Depthwise Separable CNN (DSCNN)**
This demo uses a quantized DSCNN model optimized for edge deployment. Upload audio or record directly to test keyword recognition.
**Supported Keywords:** yes, no, up, down, left, right, on, off, stop, go, silence, unknown
**Model Details:**
- Architecture: Depthwise Separable CNN (DSCNN)
- Quantization: INT8 (504KB model size)
- Accuracy: 94.5% on Google Speech Commands
- Input: MFCC features (1Γ—490)
- Optimized for: ARM Cortex-M, embedded systems
"""
)
# Launch the demo
if __name__ == "__main__":
demo.launch(share=True)