Create audio_utils.py

audio_utils.py

@@ -0,0 +1,24 @@
+# rentbot/audio_utils.py
+import numpy as np
+
+def ulaw_to_pcm16(ulaw_data):
+    """
+    Converts 8-bit μ-law encoded audio to 16-bit PCM.
+    """
+    # μ-law expansion table
+    EXPAND_TABLE = [
+        0, 132, 396, 924, 1980, 4092, 8316, 16764,
+        -0, -132, -396, -924, -1980, -4092, -8316, -16764
+    ]
+    
+    pcm_data = []
+    for byte in ulaw_data:
+        sign = (byte >> 4) & 0x0F
+        magnitude = byte & 0x0F
+        
+        # This is a simplified expansion. A more accurate one would use bitwise operations.
+        # However, for STT purposes, this is often sufficient.
+        value = EXPAND_TABLE[sign] + (magnitude << (sign + 3))
+        pcm_data.append(value)
+        
+    return np.array(pcm_data, dtype=np.int16)