audio increase

src/video_renderer.py

@@ -862,8 +862,14 @@ class VideoRenderer:
         """
         Dynamically calculate background music volume based on TTS and background RMS.
         Tuned for boosted TTS (+5 dB from Google TTS).
+        If main_rms is 0 (no TTS), treat background as main audio with high volume.
         """
 
+        # If no main audio (TTS), treat background as primary audio
+        if main_rms == 0 or main_rms < 0.001:
+            logger.info("🔊 No main audio detected, treating background as primary audio with high volume")
+            return 0.85  # High volume for background as main audio
+
         # Base volume curve (a bit higher overall)
         if main_rms > 0.04:         # Very strong TTS
             base_volume = 0.35