ltc probe

ltc_probe.py

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+#!/usr/bin/env python3
+
+"""
+ltc_probe.py
+Probes audio input to detect LTC-like signal characteristics.
+Reports zero crossings and estimated frequency.
+"""
+
+import numpy as np
+import sounddevice as sd
+
+DURATION = 1.0  # seconds
+SAMPLERATE = 48000
+CHANNELS = 1
+EXPECTED_FREQ = 2000  # Approx LTC edge rate at 25fps
+
+def count_zero_crossings(signal):
+    signal = signal.flatten()
+    signs = np.sign(signal)
+    return np.count_nonzero(np.diff(signs))
+
+def verdict(freq):
+    if freq < 100:
+        return "❌ No signal detected (flatline or silence)"
+    elif 1800 <= freq <= 2200:
+        return f"✅ LTC-like signal detected (freq: {freq:.1f} Hz)"
+    else:
+        return f"⚠️ Unstable or non-LTC signal (freq: {freq:.1f} Hz)"
+
+def main():
+    print("🔍 Capturing 1 second of audio for LTC probing...")
+    audio = sd.rec(int(DURATION * SAMPLERATE), samplerate=SAMPLERATE, channels=CHANNELS, dtype='float32')
+    sd.wait()
+
+    crossings = count_zero_crossings(audio)
+    estimated_freq = crossings / DURATION
+
+    print(f"Zero crossings: {crossings}")
+    print(f"Estimated frequency: {estimated_freq:.1f} Hz")
+    print(verdict(estimated_freq))
+
+if __name__ == "__main__":
+    main()