Update srt_utils.py

srt_utils.py

@@ -335,8 +335,20 @@ def process_audio_for_transcription(input_file: str) -> str:
     
     # "Retire qualquer música de fundo" -> Extremely hard without AI like Spleeter. 
     # But aggressive vocal isolation via EQ helps.
+    # To avoid hallucinations during silence, we need to MUTE silence, not remove it (which breaks sync).
+    # We use 'afftdn' (FFT Denoise) to aggressively reduce background noise/music floor.
+    # We can also use a 'compand' filter as a Noise Gate to silence anything below a threshold.
     
-    filters = "highpass=f=200,lowpass=f=3000,dynaudnorm=f=150:g=15"
+    # Filter Chain Strategy:
+    # 1. Highpass (300Hz) - Cut bass/rumble/drums
+    # 2. Lowpass (3000Hz) - Cut sibilance/high-hats
+    # 3. AFFTDN - Spectral noise reduction (aggressive)
+    # 4. Dynaudnorm - Normalize volume of speech
+    
+    # Check if we can use afftdn (assuming recent ffmpeg from previous output)
+    # If not, we might fail, but let's try.
+    
+    filters = "highpass=f=300,lowpass=f=3000,afftdn=nr=30:nf=-25,dynaudnorm=f=150:g=15"
     
     try:
         command = [
@@ -352,7 +364,7 @@ def process_audio_for_transcription(input_file: str) -> str:
             output_file
         ]
         
-        print(f"🔊 Processando áudio com FFmpeg: {' '.join(command)}")
+        print(f"🔊 Processando áudio com FFmpeg (Noise Gate/Spectral Cleaning): {' '.join(command)}")
         subprocess.run(command, check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
         
         if os.path.exists(output_file):