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speech_to_speech/api/openai_realtime/utils.py

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+import numpy as np
+from scipy.signal import resample_poly
+
+
+def resample(audio_int16: bytes, from_rate: int, to_rate: int) -> bytes:
+    """Resample int16 PCM audio between sample rates using polyphase filtering."""
+    if from_rate == to_rate:
+        return audio_int16
+    samples = np.frombuffer(audio_int16, dtype=np.int16).astype(np.float32) / 32768.0
+    gcd = np.gcd(to_rate, from_rate)
+    resampled = resample_poly(samples, up=to_rate // gcd, down=from_rate // gcd)
+    return np.clip(resampled * 32768, -32768, 32767).astype(np.int16).tobytes()