Experimental - Add mic sync calibration

generate_calibration_tone.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python3
+"""Generate a calibration tone FLAC (wav fallback) file with repeated logarithmic chirps."""
+
+import numpy as np
+
+# Parameters
+SAMPLE_RATE = 44100
+CHIRP_INTERVAL = 0.5  # seconds between chirp starts
+CHIRP_DURATION = 0.2  # seconds
+TOTAL_DURATION = 60  # seconds
+F_START = 100  # Hz
+F_END = 15000  # Hz
+AMPLITUDE = 0.8  # 0-1 range
+OUTPUT_FILE = "calibration_tone.flac"
+
+
+def generate_log_chirp(
+    duration: float, f0: float, f1: float, sample_rate: int
+) -> np.ndarray:
+    """Generate a logarithmic frequency sweep (chirp)."""
+    t = np.linspace(0, duration, int(sample_rate * duration), endpoint=False)
+    # Logarithmic chirp formula
+    k = (f1 / f0) ** (1 / duration)
+    phase = 2 * np.pi * f0 * (k**t - 1) / np.log(k)
+    return np.sin(phase)
+
+
+def main() -> None:
+    silence_duration = CHIRP_INTERVAL - CHIRP_DURATION
+    num_chirps = int(TOTAL_DURATION / CHIRP_INTERVAL)
+    print(f"Generating calibration tone: {num_chirps} chirps (alternating up/down)")
+    print(f"  Chirp: {CHIRP_DURATION}s sweep {F_START}Hz <-> {F_END}Hz")
+    print(f"  Interval: {CHIRP_INTERVAL}s (chirp every {int(CHIRP_INTERVAL * 1000)}ms)")
+
+    # Generate upward chirp (low to high)
+    chirp_up = generate_log_chirp(CHIRP_DURATION, F_START, F_END, SAMPLE_RATE)
+
+    # Generate downward chirp (high to low)
+    chirp_down = generate_log_chirp(CHIRP_DURATION, F_END, F_START, SAMPLE_RATE)
+
+    # Apply fade in/out to avoid clicks (20ms each)
+    fade_samples = int(0.02 * SAMPLE_RATE)
+    fade_in = np.linspace(0, 1, fade_samples)
+    fade_out = np.linspace(1, 0, fade_samples)
+
+    chirp_up[:fade_samples] *= fade_in
+    chirp_up[-fade_samples:] *= fade_out
+    chirp_down[:fade_samples] *= fade_in
+    chirp_down[-fade_samples:] *= fade_out
+
+    # Scale amplitude
+    chirp_up = chirp_up * AMPLITUDE
+    chirp_down = chirp_down * AMPLITUDE
+
+    # Generate silence
+    silence = np.zeros(int(silence_duration * SAMPLE_RATE))
+
+    # Build full sequence: alternating up/down chirps with silence
+    segments = []
+    for i in range(num_chirps):
+        chirp = chirp_up if i % 2 == 0 else chirp_down
+        segments.append(chirp)
+        if i < num_chirps - 1:  # No silence after last chirp
+            segments.append(silence)
+
+    full_signal = np.concatenate(segments)
+
+    # Pad to exact TOTAL_DURATION
+    target_samples = int(TOTAL_DURATION * SAMPLE_RATE)
+    if len(full_signal) < target_samples:
+        padding = np.zeros(target_samples - len(full_signal))
+        full_signal = np.concatenate([full_signal, padding])
+
+    # Convert to 16-bit PCM
+    audio_int16 = (full_signal * 32767).astype(np.int16)
+
+    # Save as FLAC using soundfile
+    try:
+        import soundfile as sf
+
+        sf.write(OUTPUT_FILE, audio_int16, SAMPLE_RATE, format="FLAC")
+        print(f"Saved: {OUTPUT_FILE}")
+    except ImportError:
+        # Fallback to WAV if soundfile not available
+        from scipy.io import wavfile
+
+        output_wav = OUTPUT_FILE.replace(".flac", ".wav")
+        wavfile.write(output_wav, SAMPLE_RATE, audio_int16)
+        print(f"soundfile not installed, saved as WAV: {output_wav}")
+        print("Install soundfile for FLAC: pip install soundfile")
+
+    total_duration = len(full_signal) / SAMPLE_RATE
+    print(f"Total duration: {total_duration:.1f}s")
+
+
+if __name__ == "__main__":
+    main()

pyproject.toml

@@ -21,6 +21,7 @@ dependencies = [
   "readchar>=4.0.0",
   "rich>=13.0.0",
   "sounddevice>=0.4.6",
+  "scipy>=1.16.3",
 ]
 
 description = "Synchronized audio player for Sendspin servers"