allow custom interruption strategies

CHANGELOG.md

@@ -26,12 +26,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added OpenTelemetry tracing for `GeminiMultimodalLiveLLMService` and
   `OpenAIRealtimeBetaLLMService`.
 
-- Added `interruption_strategies` to `PipelineParams` using
+- Added initial support for interruption strategies, which determine if the user
-  `MinWordsInterruptionStrategy` to specify minimum words required to interrupt
+  should interrupt the bot while the bot is speaking. Interruption strategies
-  the bot when it's speaking. Use
+  can be based on factors such as audio volume or the number of words spoken by
-  `interruption_strategies=[MinWordsInterruptionStrategy(min_words=N)]` to
+  the user. These can be specified via the new `interruption_strategies` field
-  require users to speak at least N words before interrupting. If not
+  in `PipelineParams`. A new `MinWordsInterruptionStrategy` strategy has been
-  specified, the normal interruption behavior applies.
+  introduced which triggers an interruption if the user has spoken a minimum
+  number of words. If no interruption strategies are specified, the normal
+  interruption behavior applies. If multiple strategies are provided, the first
+  one that evaluates to true will trigger the interruption.
 
 - `BaseInputTransport` now handles `StopFrame`. When a `StopFrame` is received
   the transport will pause sending frames downstream until a new `StartFrame` is

src/pipecat/audio/interruptions/base_interruption_strategy.py

@@ -0,0 +1,38 @@
+#
+# Copyright (c) 2024–2025, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+from abc import ABC, abstractmethod
+
+
+class BaseInterruptionStrategy(ABC):
+    """This is a base class for interruption strategies. Interruption strategies
+    decide when the user can interrupt the bot while the bot is speaking. For
+    example, there could be strategies based on audio volume or strategies based
+    on the number of words the user spoke.
+
+    """
+
+    async def append_audio(self, audio: bytes, sample_rate: int):
+        """Appends audio to the strategy. Not all strategies handle audio."""
+        pass
+
+    async def append_text(self, text: str):
+        """Appends text to the strategy. Not all strategies handle text."""
+        pass
+
+    @abstractmethod
+    async def should_interrupt(self) -> bool:
+        """This is called when the user stops speaking and it's time to decide
+        whether the user should interrupt the bot. The decision will be based on
+        the aggregated audio and/or text.
+
+        """
+        pass
+
+    @abstractmethod
+    async def reset(self):
+        """Reset the current accumulated text and/or audio."""
+        pass

src/pipecat/audio/interruptions/min_words_interruption_strategy.py

@@ -0,0 +1,40 @@
+#
+# Copyright (c) 2024–2025, Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+from loguru import logger
+
+from pipecat.audio.interruptions.base_interruption_strategy import BaseInterruptionStrategy
+
+
+class MinWordsInterruptionStrategy(BaseInterruptionStrategy):
+    """This is an interruption strategy based on a minimum number of words said
+    by the user. That is, the strategy will be true if the user has said at
+    least that amount of words.
+
+    """
+
+    def __init__(self, *, min_words: int):
+        super().__init__()
+        self._min_words = min_words
+        self._text = ""
+
+    async def append_text(self, text: str):
+        """Appends text for later analysis. Not all strategies need to handle
+        text.
+
+        """
+        self._text += text
+
+    async def should_interrupt(self) -> bool:
+        word_count = len(self._text.split())
+        interrupt = word_count >= self._min_words
+        logger.debug(
+            f"should_interrupt={interrupt} num_spoken_words={word_count} min_words={self._min_words}"
+        )
+        return interrupt
+
+    async def reset(self):
+        self._text = ""

src/pipecat/frames/frames.py

@@ -19,6 +19,7 @@ from typing import (
     Tuple,
 )
 
+from pipecat.audio.interruptions.base_interruption_strategy import BaseInterruptionStrategy
 from pipecat.audio.vad.vad_analyzer import VADParams
 from pipecat.metrics.metrics import MetricsData
 from pipecat.transcriptions.language import Language
@@ -439,28 +440,6 @@ class OutputDTMFFrame(DTMFFrame, DataFrame):
 #
 
 
-@dataclass
-class InterruptionStrategy:
-    """Base class for interruption strategies."""
-
-    pass
-
-
-@dataclass
-class MinWordsInterruptionStrategy(InterruptionStrategy):
-    """Strategy for interruption behavior based on a minimum number of words spoken by the user.
-
-    Args:
-        min_words: If set, user must speak at least this many words to interrupt
-    """
-
-    min_words: int
-
-    def __post_init__(self):
-        if self.min_words <= 0:
-            raise ValueError("min_words must be greater than 0")
-
-
 @dataclass
 class StartFrame(SystemFrame):
     """This is the first frame that should be pushed down a pipeline."""
@@ -471,7 +450,7 @@ class StartFrame(SystemFrame):
     enable_metrics: bool = False
     enable_usage_metrics: bool = False
     report_only_initial_ttfb: bool = False
-    interruption_strategies: Optional[Sequence[InterruptionStrategy]] = None
+    interruption_strategies: List[BaseInterruptionStrategy] = field(default_factory=list)
 
 
 @dataclass

src/pipecat/pipeline/task.py

@@ -11,6 +11,7 @@ from typing import Any, AsyncIterable, Dict, Iterable, List, Optional, Sequence,
 from loguru import logger
 from pydantic import BaseModel, ConfigDict, Field
 
+from pipecat.audio.interruptions.base_interruption_strategy import BaseInterruptionStrategy
 from pipecat.clocks.base_clock import BaseClock
 from pipecat.clocks.system_clock import SystemClock
 from pipecat.frames.frames import (
@@ -22,7 +23,6 @@ from pipecat.frames.frames import (
     ErrorFrame,
     Frame,
     HeartbeatFrame,
-    InterruptionStrategy,
     LLMFullResponseEndFrame,
     MetricsFrame,
     StartFrame,
@@ -75,7 +75,7 @@ class PipelineParams(BaseModel):
     report_only_initial_ttfb: bool = False
     send_initial_empty_metrics: bool = True
     start_metadata: Dict[str, Any] = Field(default_factory=dict)
-    interruption_strategies: Optional[Sequence[InterruptionStrategy]] = None
+    interruption_strategies: List[BaseInterruptionStrategy] = Field(default_factory=list)
 
 
 class PipelineTaskSource(FrameProcessor):

src/pipecat/processors/aggregators/llm_response.py

@@ -11,6 +11,7 @@ from typing import Dict, List, Literal, Optional, Set
 
 from loguru import logger
 
+from pipecat.audio.interruptions.base_interruption_strategy import BaseInterruptionStrategy
 from pipecat.frames.frames import (
     BotInterruptionFrame,
     BotStartedSpeakingFrame,
@@ -24,6 +25,7 @@ from pipecat.frames.frames import (
     FunctionCallInProgressFrame,
     FunctionCallResultFrame,
     FunctionCallsStartedFrame,
+    InputAudioRawFrame,
     InterimTranscriptionFrame,
     LLMFullResponseEndFrame,
     LLMFullResponseStartFrame,
@@ -33,7 +35,6 @@ from pipecat.frames.frames import (
     LLMSetToolChoiceFrame,
     LLMSetToolsFrame,
     LLMTextFrame,
-    MinWordsInterruptionStrategy,
     OpenAILLMContextAssistantTimestampFrame,
     StartFrame,
     StartInterruptionFrame,
@@ -296,6 +297,9 @@ class LLMUserContextAggregator(LLMContextResponseAggregator):
         elif isinstance(frame, CancelFrame):
             await self._cancel(frame)
             await self.push_frame(frame, direction)
+        elif isinstance(frame, InputAudioRawFrame):
+            await self._handle_input_audio(frame)
+            await self.push_frame(frame, direction)
         elif isinstance(frame, UserStartedSpeakingFrame):
             await self._handle_user_started_speaking(frame)
             await self.push_frame(frame, direction)
@@ -332,10 +336,10 @@ class LLMUserContextAggregator(LLMContextResponseAggregator):
         await self.push_frame(frame)
 
     async def push_aggregation(self):
-        """Pushes the current aggregation based on interruption configuration and conditions."""
+        """Pushes the current aggregation based on interruption strategies and conditions."""
         if len(self._aggregation) > 0:
             if self.interruption_strategies and self._bot_speaking:
-                should_interrupt = self._should_interrupt_based_on_strategies()
+                should_interrupt = await self._should_interrupt_based_on_strategies()
 
                 if should_interrupt:
                     logger.debug(
@@ -351,23 +355,19 @@ class LLMUserContextAggregator(LLMContextResponseAggregator):
                 # No interruption config - normal behavior (always push aggregation)
                 await self._process_aggregation()
 
-    def _should_interrupt_based_on_strategies(self) -> bool:
+    async def _should_interrupt_based_on_strategies(self) -> bool:
         """Check if interruption should occur based on configured strategies."""
-        if not self.interruption_strategies:
-            return False
 
-        # Check strategies one by one until first match
+        async def should_interrupt(strategy: BaseInterruptionStrategy):
-        for strategy in self.interruption_strategies:
+            await strategy.append_text(self._aggregation)
-            if isinstance(strategy, MinWordsInterruptionStrategy):
+            return await strategy.should_interrupt()
-                if self._should_interrupt_min_words(strategy):
-                    return True
 
-        return False
+        result = any([await should_interrupt(s) for s in self._interruption_strategies])
 
-    def _should_interrupt_min_words(self, strategy: MinWordsInterruptionStrategy) -> bool:
+        # Reset all strategies.
-        """Check if word count threshold is met."""
+        [await s.reset() for s in self._interruption_strategies]
-        word_count = len(self._aggregation.split())
+
-        return word_count >= strategy.min_words
+        return result
 
     async def _start(self, frame: StartFrame):
         self._create_aggregation_task()
@@ -378,6 +378,10 @@ class LLMUserContextAggregator(LLMContextResponseAggregator):
     async def _cancel(self, frame: CancelFrame):
         await self._cancel_aggregation_task()
 
+    async def _handle_input_audio(self, frame: InputAudioRawFrame):
+        for s in self.interruption_strategies:
+            await s.append_audio(frame.audio, frame.sample_rate)
+
     async def _handle_user_started_speaking(self, frame: UserStartedSpeakingFrame):
         self._user_speaking = True
         self._waiting_for_aggregation = True

src/pipecat/processors/frame_processor.py

@@ -7,16 +7,16 @@
 import asyncio
 from dataclasses import dataclass
 from enum import Enum
-from typing import Awaitable, Callable, Coroutine, Optional, Sequence
+from typing import Awaitable, Callable, Coroutine, List, Optional, Sequence
 
 from loguru import logger
 
+from pipecat.audio.interruptions.base_interruption_strategy import BaseInterruptionStrategy
 from pipecat.clocks.base_clock import BaseClock
 from pipecat.frames.frames import (
     CancelFrame,
     ErrorFrame,
     Frame,
-    InterruptionStrategy,
     StartFrame,
     StartInterruptionFrame,
     StopInterruptionFrame,
@@ -68,7 +68,7 @@ class FrameProcessor(BaseObject):
         self._enable_metrics = False
         self._enable_usage_metrics = False
         self._report_only_initial_ttfb = False
-        self._interruption_strategies: Optional[Sequence[InterruptionStrategy]] = None
+        self._interruption_strategies: List[BaseInterruptionStrategy] = []
 
         # Indicates whether we have received the StartFrame.
         self.__started = False
@@ -122,7 +122,7 @@ class FrameProcessor(BaseObject):
         return self._report_only_initial_ttfb
 
     @property
-    def interruption_strategies(self) -> Optional[Sequence[InterruptionStrategy]]:
+    def interruption_strategies(self) -> Sequence[BaseInterruptionStrategy]:
         return self._interruption_strategies
 
     def can_generate_metrics(self) -> bool:

src/pipecat/transports/base_input.py

@@ -246,7 +246,7 @@ class BaseInputTransport(FrameProcessor):
             # 1. No interruption config is set, OR
             # 2. Interruption config is set but bot is not speaking
             should_push_immediate_interruption = (
-                self.interruption_strategies is None or not self._bot_speaking
+                not self.interruption_strategies or not self._bot_speaking
             )
 
             # Make sure we notify about interruptions quickly out-of-band.

tests/test_interruption_strategies.py

@@ -0,0 +1,24 @@
+#
+# Copyright (c) 2024-2025 Daily
+#
+# SPDX-License-Identifier: BSD 2-Clause License
+#
+
+import unittest
+
+from pipecat.audio.interruptions.min_words_interruption_strategy import MinWordsInterruptionStrategy
+
+
+class TestInterruptionStrategy(unittest.IsolatedAsyncioTestCase):
+    async def test_min_words(self):
+        strategy = MinWordsInterruptionStrategy(min_words=2)
+        await strategy.append_text("Hello")
+        self.assertEqual(await strategy.should_interrupt(), False)
+        await strategy.append_text(" there!")
+        self.assertEqual(await strategy.should_interrupt(), True)
+        # Reset and check again
+        await strategy.reset()
+        await strategy.append_text("Hello!")
+        self.assertEqual(await strategy.should_interrupt(), False)
+        await strategy.append_text(" How are you?")
+        self.assertEqual(await strategy.should_interrupt(), True)