Fix TTS: use correct TTSService class, add fallback when TTS returns None

core/models.py

@@ -45,7 +45,7 @@ def generate_podcast_audio(script_text: str):
     
     try:
         from riva.client import Auth
-        from riva.client import SpeechSynthesisService
+        from riva.client import TTSService
         
         # Setup authentication for NVIDIA hosted Riva TTS
         metadata = [
@@ -53,8 +53,8 @@ def generate_podcast_audio(script_text: str):
             ("authorization", f"Bearer {api_key}")
         ]
         
-        auth = Auth(uri="grpc.nvcf.nvidia.com:443", use_ssl=True, metadata=metadata)
-        tts_service = SpeechSynthesisService(auth)
+        auth = Auth(None, True, "grpc.nvcf.nvidia.com:443", metadata)
+        tts_service = TTSService(auth)
         
         # Remove speaker labels for single-voice synthesis
         lines = script_text.split('\n')
@@ -71,18 +71,21 @@ def generate_podcast_audio(script_text: str):
         
         clean_text = ' '.join(clean_lines)
         
-        # Call TTS API
-        resp = tts_service.synthesize(
-            text=clean_text,
-            language_code="en-US",
-            encoding=1,  # LINEAR_PCM
-            sample_rate_hz=22050,  # Magpie TTS sample rate
-            voice_name="Magpie-Multilingual.EN-US.Aria"
-        )
+        # Call TTS API - use dict-style args as expected by TTSService.synthesize()
+        req = {
+            "text": clean_text,
+            "language_code": "en-US",
+            "encoding": 1,  # LINEAR_PCM
+            "sample_rate_hz": 22050,  # Magpie TTS sample rate
+            "voice_name": "Magpie-Multilingual.EN-US.Aria"
+        }
+        resp = tts_service.synthesize(**req)
         
         # resp.audio contains PCM bytes (16-bit, mono)
         return resp.audio
         
     except Exception as e:
         print(f"NVIDIA Riva TTS failed: {e}")
+        import traceback
+        traceback.print_exc()
         return None

core/podcast.py

@@ -31,7 +31,9 @@ class PodcastGenerator:
                 self.wave_file(tmp_path, data, rate=22050)
                 return tmp_path
             
-            return None
+            # If we get here, data is None - log and fallback
+            print("NVIDIA Riva TTS returned None, falling back to gTTS.")
+            raise Exception("TTS returned None")
         
         except Exception as e:
             print(f"NVIDIA Riva TTS failed: {e}. Falling back to gTTS.")