Create demo_equal_loudness_filter.py

Author: Ranjuna120

audio_filters/demo_equal_loudness_filter.py

@@ -0,0 +1,152 @@
+#!/usr/bin/env python3
+"""
+Equal Loudness Filter Demo
+
+This script demonstrates the usage of the Equal Loudness Filter for audio processing.
+It shows how the filter can be used to process audio samples and demonstrates
+the filter's behavior with different types of input signals.
+"""
+
+import math
+import sys
+from typing import List
+
+from audio_filters.equal_loudness_filter import EqualLoudnessFilter
+
+
+def generate_test_signal(frequency: float, duration: float, samplerate: int, amplitude: float = 0.5) -> List[float]:
+    """
+    Generate a simple sine wave test signal.
+    
+    Args:
+        frequency: Frequency of the sine wave in Hz
+        duration: Duration of the signal in seconds
+        samplerate: Sample rate in Hz
+        amplitude: Amplitude of the sine wave (0-1)
+    
+    Returns:
+        List of audio samples
+    """
+    samples = []
+    total_samples = int(duration * samplerate)
+    
+    for i in range(total_samples):
+        t = i / samplerate  # Time in seconds
+        sample = amplitude * math.sin(2 * math.pi * frequency * t)
+        samples.append(sample)
+    
+    return samples
+
+
+def demonstrate_equal_loudness_filter():
+    """Main demonstration function."""
+    print("🎵 Equal Loudness Filter Demonstration")
+    print("=" * 50)
+    
+    # Create filter instance
+    samplerate = 44100
+    filter_instance = EqualLoudnessFilter(samplerate)
+    
+    print(f"Filter initialized with sample rate: {samplerate} Hz")
+    print(f"Filter order: {filter_instance.yulewalk_filter.order}")
+    print()
+    
+    # Test 1: Process silence
+    print("📌 Test 1: Processing silence")
+    silence_result = filter_instance.process(0.0)
+    print(f"Input: 0.0 → Output: {silence_result}")
+    assert silence_result == 0.0, "Silence should remain silence"
+    print("✅ Silence test passed!")
+    print()
+    
+    # Test 2: Process various amplitude levels
+    print("📌 Test 2: Processing different amplitude levels")
+    test_amplitudes = [0.1, 0.25, 0.5, 0.75, 1.0, -0.1, -0.25, -0.5, -0.75, -1.0]
+    
+    for amplitude in test_amplitudes:
+        result = filter_instance.process(amplitude)
+        print(f"Input: {amplitude:6.2f} → Output: {result:10.6f}")
+    print("✅ Amplitude test completed!")
+    print()
+    
+    # Test 3: Process a sine wave
+    print("📌 Test 3: Processing a 1kHz sine wave")
+    test_freq = 1000  # 1kHz
+    duration = 0.01   # 10ms
+    sine_wave = generate_test_signal(test_freq, duration, samplerate, 0.3)
+    
+    print(f"Generated {len(sine_wave)} samples of {test_freq}Hz sine wave")
+    
+    # Process the sine wave
+    filtered_samples = []
+    for sample in sine_wave[:10]:  # Show first 10 samples
+        filtered_sample = filter_instance.process(sample)
+        filtered_samples.append(filtered_sample)
+        print(f"Sample: {sample:8.5f} → Filtered: {filtered_sample:8.5f}")
+    
+    print("✅ Sine wave processing test completed!")
+    print()
+    
+    # Test 4: Filter reset functionality
+    print("📌 Test 4: Testing filter reset")
+    
+    # Process some samples to build internal state
+    for _ in range(5):
+        filter_instance.process(0.5)
+    
+    print("Processed 5 samples to build internal state")
+    
+    # Check state before reset
+    history_before = filter_instance.yulewalk_filter.input_history.copy()
+    print(f"Input history before reset: {history_before[:3]}...")  # Show first 3 values
+    
+    # Reset the filter
+    filter_instance.reset()
+    
+    # Check state after reset
+    history_after = filter_instance.yulewalk_filter.input_history.copy()
+    print(f"Input history after reset: {history_after[:3]}...")
+    
+    assert all(val == 0.0 for val in history_after), "History should be cleared after reset"
+    print("✅ Reset test passed!")
+    print()
+    
+    # Test 5: Filter information
+    print("📌 Test 5: Filter configuration information")
+    filter_info = filter_instance.get_filter_info()
+    
+    for key, value in filter_info.items():
+        if isinstance(value, list):
+            print(f"{key}: [{len(value)} coefficients]")
+        else:
+            print(f"{key}: {value}")
+    
+    print("✅ Filter info test completed!")
+    print()
+    
+    # Test 6: Different sample rates
+    print("📌 Test 6: Testing different sample rates")
+    test_samplerates = [22050, 44100, 48000, 96000]
+    
+    for sr in test_samplerates:
+        test_filter = EqualLoudnessFilter(sr)
+        result = test_filter.process(0.5)
+        print(f"Sample rate: {sr:6d} Hz → Result: {result:10.6f}")
+    
+    print("✅ Sample rate test completed!")
+    print()
+    
+    print("🎉 All demonstrations completed successfully!")
+    print("\nThe Equal Loudness Filter is ready for use in audio processing applications!")
+
+
+if __name__ == "__main__":
+    try:
+        demonstrate_equal_loudness_filter()
+    except ImportError as e:
+        print(f"❌ Import error: {e}")
+        print("Please ensure numpy is installed: pip install numpy")
+        sys.exit(1)
+    except Exception as e:
+        print(f"❌ Demonstration failed: {e}")
+        sys.exit(1)