services(tts): make sure word timestamp is reset properly

src/pipecat/services/ai_services.py

@@ -391,7 +391,6 @@ class WordTTSService(TTSService):
 
     def reset_word_timestamps(self):
         self._initial_word_timestamp = -1
-        self._word_timestamps = []
 
     async def add_word_timestamps(self, word_times: List[Tuple[str, float]]):
         for word, timestamp in word_times:
@@ -426,7 +425,10 @@ class WordTTSService(TTSService):
         while True:
             try:
                 (word, timestamp) = await self._words_queue.get()
-                if word == "LLMFullResponseEndFrame" and timestamp == 0:
+                if word == "Reset" and timestamp == 0:
+                    self.reset_word_timestamps()
+                    frame = None
+                elif word == "LLMFullResponseEndFrame" and timestamp == 0:
                     frame = LLMFullResponseEndFrame()
                     frame.pts = last_pts
                 elif word == "TTSStoppedFrame" and timestamp == 0:
@@ -435,8 +437,9 @@ class WordTTSService(TTSService):
                 else:
                     frame = TextFrame(word)
                     frame.pts = self._initial_word_timestamp + timestamp
-                last_pts = frame.pts
-                await self.push_frame(frame)
+                if frame:
+                    last_pts = frame.pts
+                    await self.push_frame(frame)
                 self._words_queue.task_done()
             except asyncio.CancelledError:
                 break

src/pipecat/services/cartesia.py

@@ -234,7 +234,7 @@ class CartesiaTTSService(WordTTSService):
                     # timestamp to set send context frames.
                     self._context_id = None
                     await self.add_word_timestamps(
-                        [("TTSStoppedFrame", 0), ("LLMFullResponseEndFrame", 0)]
+                        [("TTSStoppedFrame", 0), ("LLMFullResponseEndFrame", 0), ("Reset", 0)]
                     )
                 elif msg["type"] == "timestamps":
                     await self.add_word_timestamps(

src/pipecat/services/elevenlabs.py

@@ -286,7 +286,7 @@ class ElevenLabsTTSService(WordTTSService):
         if isinstance(frame, (TTSStoppedFrame, StartInterruptionFrame)):
             self._started = False
             if isinstance(frame, TTSStoppedFrame):
-                await self.add_word_timestamps([("LLMFullResponseEndFrame", 0)])
+                await self.add_word_timestamps([("LLMFullResponseEndFrame", 0), ("Reset", 0)])
 
     async def process_frame(self, frame: Frame, direction: FrameDirection):
         await super().process_frame(frame, direction)