MinWordsUserTurnStartStrategy: avoid using interim transcriptions

Using a mix of interim and final transcriptions caused incorrect behavior; using
only interim transcriptions alone also produced undesired results.

src/pipecat/turns/user_start/min_words_user_turn_start_strategy.py

@@ -12,7 +12,6 @@ from pipecat.frames.frames import (
     BotStartedSpeakingFrame,
     BotStoppedSpeakingFrame,
     Frame,
-    InterimTranscriptionFrame,
     TranscriptionFrame,
 )
 from pipecat.turns.user_start.base_user_turn_start_strategy import BaseUserTurnStartStrategy
@@ -23,23 +22,19 @@ class MinWordsUserTurnStartStrategy(BaseUserTurnStartStrategy):
 
     This strategy signals the start of a user turn once the user has spoken at
     least a specified number of words, as determined from transcription frames.
-    Optionally, interim transcriptions can be used for earlier detection.
 
     """
 
-    def __init__(self, *, min_words: int, use_interim: bool = True, **kwargs):
+    def __init__(self, *, min_words: int, **kwargs):
         """Initialize the minimum words bot turn start strategy.
 
         Args:
             min_words: Minimum number of spoken words required to trigger the
                 start of a user turn.
-            use_interim: Whether to consider interim transcription frames for
-                earlier detection.
             **kwargs: Additional keyword arguments.
         """
         super().__init__(**kwargs)
         self._min_words = min_words
-        self._use_interim = use_interim
         self._bot_speaking = False
         self._text = ""
 
@@ -66,8 +61,6 @@ class MinWordsUserTurnStartStrategy(BaseUserTurnStartStrategy):
             await self._handle_bot_stopped_speaking(frame)
         elif isinstance(frame, TranscriptionFrame):
             await self._handle_transcription(frame)
-        elif isinstance(frame, InterimTranscriptionFrame) and self._use_interim:
-            await self._handle_interim_transcription(frame)
 
     async def _handle_bot_started_speaking(self, frame: BotStartedSpeakingFrame):
         """Handle bot started speaking frame.
@@ -95,7 +88,7 @@ class MinWordsUserTurnStartStrategy(BaseUserTurnStartStrategy):
         Args:
             frame: The transcription frame to be processed.
         """
-        self._text += frame.text
+        self._text += f" {frame.text}"
 
         min_words = self._min_words if self._bot_speaking else 1
 
@@ -109,22 +102,3 @@ class MinWordsUserTurnStartStrategy(BaseUserTurnStartStrategy):
 
         if should_trigger:
             await self.trigger_user_turn_started()
-
-    async def _handle_interim_transcription(self, frame: InterimTranscriptionFrame):
-        """Handle an interim transcription frame and check word count.
-
-        Args:
-            frame: The interim transcription frame to be processed.
-        """
-        min_words = self._min_words if self._bot_speaking else 1
-
-        word_count = len(frame.text.split())
-        should_trigger = word_count >= min_words
-
-        logger.debug(
-            f"{self} interim=True should_trigger={should_trigger} num_spoken_words={word_count} "
-            f"min_words={min_words} bot_speaking={self._bot_speaking}"
-        )
-
-        if should_trigger:
-            await self.trigger_user_turn_started()

tests/test_user_turn_start_strategy.py

@@ -24,7 +24,7 @@ from pipecat.turns.user_start import (
 
 class TestMinWordsInterruptionStrategy(unittest.IsolatedAsyncioTestCase):
     async def test_bot_speaking_transcriptions(self):
-        strategy = MinWordsUserTurnStartStrategy(min_words=2)
+        strategy = MinWordsUserTurnStartStrategy(min_words=3)
 
         should_start = None
 
@@ -38,7 +38,7 @@ class TestMinWordsInterruptionStrategy(unittest.IsolatedAsyncioTestCase):
         self.assertFalse(should_start)
 
         await strategy.process_frame(
-            TranscriptionFrame(text=" there!", user_id="cat", timestamp="")
+            TranscriptionFrame(text=" there friend!", user_id="cat", timestamp="")
         )
         self.assertTrue(should_start)
 
@@ -50,54 +50,14 @@ class TestMinWordsInterruptionStrategy(unittest.IsolatedAsyncioTestCase):
         await strategy.process_frame(TranscriptionFrame(text="Hello!", user_id="cat", timestamp=""))
         self.assertFalse(should_start)
 
+        await strategy.process_frame(TranscriptionFrame(text="How", user_id="cat", timestamp=""))
+        self.assertFalse(should_start)
+
         await strategy.process_frame(
             TranscriptionFrame(text="How are you?", user_id="cat", timestamp="")
         )
         self.assertTrue(should_start)
 
-    async def test_bot_speaking_interim_transcriptions(self):
-        strategy = MinWordsUserTurnStartStrategy(min_words=2)
-
-        should_start = None
-
-        @strategy.event_handler("on_user_turn_started")
-        async def on_user_turn_started(strategy, params):
-            nonlocal should_start
-            should_start = True
-
-        await strategy.process_frame(BotStartedSpeakingFrame())
-        await strategy.process_frame(
-            InterimTranscriptionFrame(text="Hello", user_id="cat", timestamp="")
-        )
-        self.assertFalse(should_start)
-
-        await strategy.process_frame(BotStartedSpeakingFrame())
-        await strategy.process_frame(
-            InterimTranscriptionFrame(text="Hello there!", user_id="cat", timestamp="")
-        )
-        self.assertTrue(should_start)
-
-    async def test_bot_speaking_all_transcriptions(self):
-        strategy = MinWordsUserTurnStartStrategy(min_words=2)
-
-        should_start = None
-
-        @strategy.event_handler("on_user_turn_started")
-        async def on_user_turn_started(strategy, params):
-            nonlocal should_start
-            should_start = True
-
-        await strategy.process_frame(BotStartedSpeakingFrame())
-        await strategy.process_frame(
-            InterimTranscriptionFrame(text="Hello", user_id="cat", timestamp="")
-        )
-        self.assertFalse(should_start)
-
-        await strategy.process_frame(
-            TranscriptionFrame(text="Hello there!", user_id="cat", timestamp="")
-        )
-        self.assertTrue(should_start)
-
     async def test_bot_not_speaking_transcriptions(self):
         strategy = MinWordsUserTurnStartStrategy(min_words=2)
 
@@ -111,21 +71,6 @@ class TestMinWordsInterruptionStrategy(unittest.IsolatedAsyncioTestCase):
         await strategy.process_frame(TranscriptionFrame(text="Hello", user_id="cat", timestamp=""))
         self.assertTrue(should_start)
 
-    async def test_bot_not_speaking_interim_transcriptions(self):
-        strategy = MinWordsUserTurnStartStrategy(min_words=2)
-
-        should_start = None
-
-        @strategy.event_handler("on_user_turn_started")
-        async def on_user_turn_started(strategy, params):
-            nonlocal should_start
-            should_start = True
-
-        await strategy.process_frame(
-            InterimTranscriptionFrame(text="Hello", user_id="cat", timestamp="")
-        )
-        self.assertTrue(should_start)
-
 
 class TestVADUserTurnStartStrategy(unittest.IsolatedAsyncioTestCase):
     async def test_vad_strategy(self):