OpenAITTSService: Add warning about changing sample_rate

src/pipecat/services/openai.py

@@ -28,6 +28,7 @@ from pipecat.frames.frames import (
     LLMTextFrame,
     LLMUpdateSettingsFrame,
     OpenAILLMContextAssistantTimestampFrame,
+    StartFrame,
     StartInterruptionFrame,
     TTSAudioRawFrame,
     TTSStartedFrame,
@@ -412,6 +413,8 @@ class OpenAITTSService(TTSService):
     The service returns PCM-encoded audio at the specified sample rate.
     """
 
+    OPENAI_SAMPLE_RATE = 24000  # OpenAI TTS always outputs at 24kHz
+
     def __init__(
         self,
         *,
@@ -421,6 +424,11 @@ class OpenAITTSService(TTSService):
         sample_rate: Optional[int] = None,
         **kwargs,
     ):
+        if sample_rate and sample_rate != self.OPENAI_SAMPLE_RATE:
+            logger.warning(
+                f"OpenAI TTS only supports {self.OPENAI_SAMPLE_RATE}Hz sample rate. "
+                f"Current rate of {self.sample_rate}Hz may cause issues."
+            )
         super().__init__(sample_rate=sample_rate, **kwargs)
 
         self.set_model_name(model)
@@ -435,6 +443,14 @@ class OpenAITTSService(TTSService):
         logger.info(f"Switching TTS model to: [{model}]")
         self.set_model_name(model)
 
+    async def start(self, frame: StartFrame):
+        await super().start(frame)
+        if self.sample_rate != self.OPENAI_SAMPLE_RATE:
+            logger.warning(
+                f"OpenAI TTS requires {self.OPENAI_SAMPLE_RATE}Hz sample rate. "
+                f"Current rate of {self.sample_rate}Hz may cause issues."
+            )
+
     async def run_tts(self, text: str) -> AsyncGenerator[Frame, None]:
         logger.debug(f"Generating TTS: [{text}]")
         try: