I can use text to get audio response and barge in

This commit is contained in:
Xin Wang
2026-01-29 16:25:53 +08:00
parent cd90b4fb37
commit ac0c76e6e8
16 changed files with 3394 additions and 119 deletions

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@@ -1 +1,22 @@
"""Core Components Package"""
from core.events import EventBus, get_event_bus
from core.transports import BaseTransport, SocketTransport, WebRtcTransport
from core.pipeline import AudioPipeline
from core.session import Session
from core.conversation import ConversationManager, ConversationState, ConversationTurn
from core.duplex_pipeline import DuplexPipeline
__all__ = [
"EventBus",
"get_event_bus",
"BaseTransport",
"SocketTransport",
"WebRtcTransport",
"AudioPipeline",
"Session",
"ConversationManager",
"ConversationState",
"ConversationTurn",
"DuplexPipeline",
]

255
core/conversation.py Normal file
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"""Conversation management for voice AI.
Handles conversation context, turn-taking, and message history
for multi-turn voice conversations.
"""
import asyncio
from typing import List, Optional, Dict, Any, Callable, Awaitable
from dataclasses import dataclass, field
from enum import Enum
from loguru import logger
from services.base import LLMMessage
class ConversationState(Enum):
"""State of the conversation."""
IDLE = "idle" # Waiting for user input
LISTENING = "listening" # User is speaking
PROCESSING = "processing" # Processing user input (LLM)
SPEAKING = "speaking" # Bot is speaking
INTERRUPTED = "interrupted" # Bot was interrupted
@dataclass
class ConversationTurn:
"""A single turn in the conversation."""
role: str # "user" or "assistant"
text: str
audio_duration_ms: Optional[int] = None
timestamp: float = field(default_factory=lambda: asyncio.get_event_loop().time())
was_interrupted: bool = False
class ConversationManager:
"""
Manages conversation state and history.
Provides:
- Message history for LLM context
- Turn management
- State tracking
- Event callbacks for state changes
"""
def __init__(
self,
system_prompt: Optional[str] = None,
max_history: int = 20,
greeting: Optional[str] = None
):
"""
Initialize conversation manager.
Args:
system_prompt: System prompt for LLM
max_history: Maximum number of turns to keep
greeting: Optional greeting message when conversation starts
"""
self.system_prompt = system_prompt or (
"You are a helpful, friendly voice assistant. "
"Keep your responses concise and conversational. "
"Respond naturally as if having a phone conversation. "
"If you don't understand something, ask for clarification."
)
self.max_history = max_history
self.greeting = greeting
# State
self.state = ConversationState.IDLE
self.turns: List[ConversationTurn] = []
# Callbacks
self._state_callbacks: List[Callable[[ConversationState, ConversationState], Awaitable[None]]] = []
self._turn_callbacks: List[Callable[[ConversationTurn], Awaitable[None]]] = []
# Current turn tracking
self._current_user_text: str = ""
self._current_assistant_text: str = ""
logger.info("ConversationManager initialized")
def on_state_change(
self,
callback: Callable[[ConversationState, ConversationState], Awaitable[None]]
) -> None:
"""Register callback for state changes."""
self._state_callbacks.append(callback)
def on_turn_complete(
self,
callback: Callable[[ConversationTurn], Awaitable[None]]
) -> None:
"""Register callback for turn completion."""
self._turn_callbacks.append(callback)
async def set_state(self, new_state: ConversationState) -> None:
"""Set conversation state and notify listeners."""
if new_state != self.state:
old_state = self.state
self.state = new_state
logger.debug(f"Conversation state: {old_state.value} -> {new_state.value}")
for callback in self._state_callbacks:
try:
await callback(old_state, new_state)
except Exception as e:
logger.error(f"State callback error: {e}")
def get_messages(self) -> List[LLMMessage]:
"""
Get conversation history as LLM messages.
Returns:
List of LLMMessage objects including system prompt
"""
messages = [LLMMessage(role="system", content=self.system_prompt)]
# Add conversation history
for turn in self.turns[-self.max_history:]:
messages.append(LLMMessage(role=turn.role, content=turn.text))
# Add current user text if any
if self._current_user_text:
messages.append(LLMMessage(role="user", content=self._current_user_text))
return messages
async def start_user_turn(self) -> None:
"""Signal that user has started speaking."""
await self.set_state(ConversationState.LISTENING)
self._current_user_text = ""
async def update_user_text(self, text: str, is_final: bool = False) -> None:
"""
Update current user text (from ASR).
Args:
text: Transcribed text
is_final: Whether this is the final transcript
"""
self._current_user_text = text
async def end_user_turn(self, text: str) -> None:
"""
End user turn and add to history.
Args:
text: Final user text
"""
if text.strip():
turn = ConversationTurn(role="user", text=text.strip())
self.turns.append(turn)
for callback in self._turn_callbacks:
try:
await callback(turn)
except Exception as e:
logger.error(f"Turn callback error: {e}")
logger.info(f"User: {text[:50]}...")
self._current_user_text = ""
await self.set_state(ConversationState.PROCESSING)
async def start_assistant_turn(self) -> None:
"""Signal that assistant has started speaking."""
await self.set_state(ConversationState.SPEAKING)
self._current_assistant_text = ""
async def update_assistant_text(self, text: str) -> None:
"""
Update current assistant text (streaming).
Args:
text: Text chunk from LLM
"""
self._current_assistant_text += text
async def end_assistant_turn(self, was_interrupted: bool = False) -> None:
"""
End assistant turn and add to history.
Args:
was_interrupted: Whether the turn was interrupted by user
"""
text = self._current_assistant_text.strip()
if text:
turn = ConversationTurn(
role="assistant",
text=text,
was_interrupted=was_interrupted
)
self.turns.append(turn)
for callback in self._turn_callbacks:
try:
await callback(turn)
except Exception as e:
logger.error(f"Turn callback error: {e}")
status = " (interrupted)" if was_interrupted else ""
logger.info(f"Assistant{status}: {text[:50]}...")
self._current_assistant_text = ""
if was_interrupted:
await self.set_state(ConversationState.INTERRUPTED)
else:
await self.set_state(ConversationState.IDLE)
async def interrupt(self) -> None:
"""Handle interruption (barge-in)."""
if self.state == ConversationState.SPEAKING:
await self.end_assistant_turn(was_interrupted=True)
def reset(self) -> None:
"""Reset conversation history."""
self.turns = []
self._current_user_text = ""
self._current_assistant_text = ""
self.state = ConversationState.IDLE
logger.info("Conversation reset")
@property
def turn_count(self) -> int:
"""Get number of turns in conversation."""
return len(self.turns)
@property
def last_user_text(self) -> Optional[str]:
"""Get last user text."""
for turn in reversed(self.turns):
if turn.role == "user":
return turn.text
return None
@property
def last_assistant_text(self) -> Optional[str]:
"""Get last assistant text."""
for turn in reversed(self.turns):
if turn.role == "assistant":
return turn.text
return None
def get_context_summary(self) -> Dict[str, Any]:
"""Get a summary of conversation context."""
return {
"state": self.state.value,
"turn_count": self.turn_count,
"last_user": self.last_user_text,
"last_assistant": self.last_assistant_text,
"current_user": self._current_user_text or None,
"current_assistant": self._current_assistant_text or None
}

509
core/duplex_pipeline.py Normal file
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@@ -0,0 +1,509 @@
"""Full duplex audio pipeline for AI voice conversation.
This module implements the core duplex pipeline that orchestrates:
- VAD (Voice Activity Detection)
- EOU (End of Utterance) Detection
- ASR (Automatic Speech Recognition) - optional
- LLM (Language Model)
- TTS (Text-to-Speech)
Inspired by pipecat's frame-based architecture and active-call's
event-driven design.
"""
import asyncio
from typing import Optional, Callable, Awaitable
from loguru import logger
from core.transports import BaseTransport
from core.conversation import ConversationManager, ConversationState
from core.events import get_event_bus
from processors.vad import VADProcessor, SileroVAD
from processors.eou import EouDetector
from services.base import BaseLLMService, BaseTTSService, BaseASRService
from services.llm import OpenAILLMService, MockLLMService
from services.tts import EdgeTTSService, MockTTSService
from services.asr import BufferedASRService
from services.siliconflow_tts import SiliconFlowTTSService
from app.config import settings
class DuplexPipeline:
"""
Full duplex audio pipeline for AI voice conversation.
Handles bidirectional audio flow with:
- User speech detection and transcription
- AI response generation
- Text-to-speech synthesis
- Barge-in (interruption) support
Architecture (inspired by pipecat):
User Audio → VAD → EOU → [ASR] → LLM → TTS → Audio Out
Barge-in Detection → Interrupt
"""
def __init__(
self,
transport: BaseTransport,
session_id: str,
llm_service: Optional[BaseLLMService] = None,
tts_service: Optional[BaseTTSService] = None,
asr_service: Optional[BaseASRService] = None,
system_prompt: Optional[str] = None,
greeting: Optional[str] = None
):
"""
Initialize duplex pipeline.
Args:
transport: Transport for sending audio/events
session_id: Session identifier
llm_service: LLM service (defaults to OpenAI)
tts_service: TTS service (defaults to EdgeTTS)
asr_service: ASR service (optional)
system_prompt: System prompt for LLM
greeting: Optional greeting to speak on start
"""
self.transport = transport
self.session_id = session_id
self.event_bus = get_event_bus()
# Initialize VAD
self.vad_model = SileroVAD(
model_path=settings.vad_model_path,
sample_rate=settings.sample_rate
)
self.vad_processor = VADProcessor(
vad_model=self.vad_model,
threshold=settings.vad_threshold
)
# Initialize EOU detector
self.eou_detector = EouDetector(
silence_threshold_ms=600,
min_speech_duration_ms=200
)
# Initialize services
self.llm_service = llm_service
self.tts_service = tts_service
self.asr_service = asr_service or BufferedASRService()
# Conversation manager
self.conversation = ConversationManager(
system_prompt=system_prompt,
greeting=greeting
)
# State
self._running = True
self._is_bot_speaking = False
self._current_turn_task: Optional[asyncio.Task] = None
self._audio_buffer: bytes = b""
self._last_vad_status: str = "Silence"
# Interruption handling
self._interrupt_event = asyncio.Event()
logger.info(f"DuplexPipeline initialized for session {session_id}")
async def start(self) -> None:
"""Start the pipeline and connect services."""
try:
# Connect LLM service
if not self.llm_service:
if settings.openai_api_key:
self.llm_service = OpenAILLMService(
api_key=settings.openai_api_key,
base_url=settings.openai_api_url,
model=settings.llm_model
)
else:
logger.warning("No OpenAI API key - using mock LLM")
self.llm_service = MockLLMService()
await self.llm_service.connect()
# Connect TTS service
if not self.tts_service:
if settings.tts_provider == "siliconflow" and settings.siliconflow_api_key:
self.tts_service = SiliconFlowTTSService(
api_key=settings.siliconflow_api_key,
voice=settings.tts_voice,
model=settings.siliconflow_tts_model,
sample_rate=settings.sample_rate,
speed=settings.tts_speed
)
logger.info("Using SiliconFlow TTS service")
else:
self.tts_service = EdgeTTSService(
voice=settings.tts_voice,
sample_rate=settings.sample_rate
)
logger.info("Using Edge TTS service")
await self.tts_service.connect()
# Connect ASR service
await self.asr_service.connect()
logger.info("DuplexPipeline services connected")
# Speak greeting if configured
if self.conversation.greeting:
await self._speak(self.conversation.greeting)
except Exception as e:
logger.error(f"Failed to start pipeline: {e}")
raise
async def process_audio(self, pcm_bytes: bytes) -> None:
"""
Process incoming audio chunk.
This is the main entry point for audio from the user.
Args:
pcm_bytes: PCM audio data (16-bit, mono, 16kHz)
"""
if not self._running:
return
try:
# 1. Process through VAD
vad_result = self.vad_processor.process(pcm_bytes, settings.chunk_size_ms)
vad_status = "Silence"
if vad_result:
event_type, probability = vad_result
vad_status = "Speech" if event_type == "speaking" else "Silence"
# Emit VAD event
await self.event_bus.publish(event_type, {
"trackId": self.session_id,
"probability": probability
})
else:
# No state change - keep previous status
vad_status = self._last_vad_status
# Update state based on VAD
if vad_status == "Speech" and self._last_vad_status != "Speech":
await self._on_speech_start()
self._last_vad_status = vad_status
# 2. Check for barge-in (user speaking while bot speaking)
if self._is_bot_speaking and vad_status == "Speech":
await self._handle_barge_in()
# 3. Buffer audio for ASR
if vad_status == "Speech" or self.conversation.state == ConversationState.LISTENING:
self._audio_buffer += pcm_bytes
await self.asr_service.send_audio(pcm_bytes)
# 4. Check for End of Utterance
if self.eou_detector.process(vad_status):
await self._on_end_of_utterance()
except Exception as e:
logger.error(f"Pipeline audio processing error: {e}", exc_info=True)
async def process_text(self, text: str) -> None:
"""
Process text input (chat command).
Allows direct text input to bypass ASR.
Args:
text: User text input
"""
if not self._running:
return
logger.info(f"Processing text input: {text[:50]}...")
# Cancel any current speaking
await self._stop_current_speech()
# Start new turn
await self.conversation.end_user_turn(text)
self._current_turn_task = asyncio.create_task(self._handle_turn(text))
async def interrupt(self) -> None:
"""Interrupt current bot speech (manual interrupt command)."""
await self._handle_barge_in()
async def _on_speech_start(self) -> None:
"""Handle user starting to speak."""
if self.conversation.state == ConversationState.IDLE:
await self.conversation.start_user_turn()
self._audio_buffer = b""
self.eou_detector.reset()
logger.debug("User speech started")
async def _on_end_of_utterance(self) -> None:
"""Handle end of user utterance."""
if self.conversation.state != ConversationState.LISTENING:
return
# Get transcribed text (if using ASR that provides it)
user_text = ""
if hasattr(self.asr_service, 'get_and_clear_text'):
user_text = self.asr_service.get_and_clear_text()
# If no ASR text, we could use the audio buffer for external ASR
# For now, just use placeholder if no ASR text
if not user_text:
# In a real implementation, you'd send audio_buffer to ASR here
# For demo purposes, use mock text
user_text = "[User speech detected]"
logger.warning("No ASR text available - using placeholder")
logger.info(f"EOU detected - user said: {user_text[:50]}...")
# Clear buffers
self._audio_buffer = b""
# Process the turn
await self.conversation.end_user_turn(user_text)
self._current_turn_task = asyncio.create_task(self._handle_turn(user_text))
async def _handle_turn(self, user_text: str) -> None:
"""
Handle a complete conversation turn.
Uses sentence-by-sentence streaming TTS for lower latency.
Args:
user_text: User's transcribed text
"""
try:
# Get AI response (streaming)
messages = self.conversation.get_messages()
full_response = ""
await self.conversation.start_assistant_turn()
self._is_bot_speaking = True
self._interrupt_event.clear()
# Sentence buffer for streaming TTS
sentence_buffer = ""
sentence_ends = {'.', '!', '?', '', '', '', '', '\n'}
first_audio_sent = False
# Stream LLM response and TTS sentence by sentence
async for text_chunk in self.llm_service.generate_stream(messages):
if self._interrupt_event.is_set():
break
full_response += text_chunk
sentence_buffer += text_chunk
await self.conversation.update_assistant_text(text_chunk)
# Check for sentence completion - synthesize immediately for low latency
while any(end in sentence_buffer for end in sentence_ends):
# Find first sentence end
min_idx = len(sentence_buffer)
for end in sentence_ends:
idx = sentence_buffer.find(end)
if idx != -1 and idx < min_idx:
min_idx = idx
if min_idx < len(sentence_buffer):
sentence = sentence_buffer[:min_idx + 1].strip()
sentence_buffer = sentence_buffer[min_idx + 1:]
if sentence and not self._interrupt_event.is_set():
# Send track start on first audio
if not first_audio_sent:
await self.transport.send_event({
"event": "trackStart",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
first_audio_sent = True
# Synthesize and send this sentence immediately
await self._speak_sentence(sentence)
else:
break
# Speak any remaining text
if sentence_buffer.strip() and not self._interrupt_event.is_set():
if not first_audio_sent:
await self.transport.send_event({
"event": "trackStart",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
first_audio_sent = True
await self._speak_sentence(sentence_buffer.strip())
# Send track end
if first_audio_sent:
await self.transport.send_event({
"event": "trackEnd",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
# End assistant turn
await self.conversation.end_assistant_turn(
was_interrupted=self._interrupt_event.is_set()
)
except asyncio.CancelledError:
logger.info("Turn handling cancelled")
await self.conversation.end_assistant_turn(was_interrupted=True)
except Exception as e:
logger.error(f"Turn handling error: {e}", exc_info=True)
await self.conversation.end_assistant_turn(was_interrupted=True)
finally:
self._is_bot_speaking = False
async def _speak_sentence(self, text: str) -> None:
"""
Synthesize and send a single sentence.
Args:
text: Sentence to speak
"""
if not text.strip() or self._interrupt_event.is_set():
return
try:
async for chunk in self.tts_service.synthesize_stream(text):
if self._interrupt_event.is_set():
break
await self.transport.send_audio(chunk.audio)
await asyncio.sleep(0.005) # Small delay to prevent flooding
except Exception as e:
logger.error(f"TTS sentence error: {e}")
async def _speak(self, text: str) -> None:
"""
Synthesize and send speech.
Args:
text: Text to speak
"""
if not text.strip():
return
try:
# Send track start event
await self.transport.send_event({
"event": "trackStart",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
self._is_bot_speaking = True
# Stream TTS audio
async for chunk in self.tts_service.synthesize_stream(text):
if self._interrupt_event.is_set():
logger.info("TTS interrupted by barge-in")
break
# Send audio to client
await self.transport.send_audio(chunk.audio)
# Small delay to prevent flooding
await asyncio.sleep(0.01)
# Send track end event
await self.transport.send_event({
"event": "trackEnd",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
except asyncio.CancelledError:
logger.info("TTS cancelled")
raise
except Exception as e:
logger.error(f"TTS error: {e}")
finally:
self._is_bot_speaking = False
async def _handle_barge_in(self) -> None:
"""Handle user barge-in (interruption)."""
if not self._is_bot_speaking:
return
logger.info("Barge-in detected - interrupting bot speech")
# Signal interruption
self._interrupt_event.set()
# Cancel TTS
if self.tts_service:
await self.tts_service.cancel()
# Cancel LLM
if self.llm_service and hasattr(self.llm_service, 'cancel'):
self.llm_service.cancel()
# Interrupt conversation
await self.conversation.interrupt()
# Send interrupt event to client
await self.transport.send_event({
"event": "interrupt",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
# Reset for new user turn
self._is_bot_speaking = False
await self.conversation.start_user_turn()
self._audio_buffer = b""
self.eou_detector.reset()
async def _stop_current_speech(self) -> None:
"""Stop any current speech task."""
if self._current_turn_task and not self._current_turn_task.done():
self._interrupt_event.set()
self._current_turn_task.cancel()
try:
await self._current_turn_task
except asyncio.CancelledError:
pass
self._is_bot_speaking = False
self._interrupt_event.clear()
async def cleanup(self) -> None:
"""Cleanup pipeline resources."""
logger.info(f"Cleaning up DuplexPipeline for session {self.session_id}")
self._running = False
await self._stop_current_speech()
# Disconnect services
if self.llm_service:
await self.llm_service.disconnect()
if self.tts_service:
await self.tts_service.disconnect()
if self.asr_service:
await self.asr_service.disconnect()
def _get_timestamp_ms(self) -> int:
"""Get current timestamp in milliseconds."""
import time
return int(time.time() * 1000)
@property
def is_speaking(self) -> bool:
"""Check if bot is currently speaking."""
return self._is_bot_speaking
@property
def state(self) -> ConversationState:
"""Get current conversation state."""
return self.conversation.state

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@@ -8,6 +8,7 @@ from loguru import logger
from core.transports import BaseTransport
from core.pipeline import AudioPipeline
from models.commands import parse_command, TTSCommand, ChatCommand, InterruptCommand, HangupCommand
from app.config import settings
class Session:
@@ -15,28 +16,44 @@ class Session:
Manages a single call session.
Handles command routing, audio processing, and session lifecycle.
Supports both basic audio pipeline and full duplex voice conversation.
"""
def __init__(self, session_id: str, transport: BaseTransport):
def __init__(self, session_id: str, transport: BaseTransport, use_duplex: bool = None):
"""
Initialize session.
Args:
session_id: Unique session identifier
transport: Transport instance for communication
use_duplex: Whether to use duplex pipeline (defaults to settings.duplex_enabled)
"""
self.id = session_id
self.transport = transport
self.pipeline = AudioPipeline(transport, session_id)
# Determine pipeline mode
self.use_duplex = use_duplex if use_duplex is not None else settings.duplex_enabled
if self.use_duplex:
from core.duplex_pipeline import DuplexPipeline
self.pipeline = DuplexPipeline(
transport=transport,
session_id=session_id,
system_prompt=settings.duplex_system_prompt,
greeting=settings.duplex_greeting
)
else:
self.pipeline = AudioPipeline(transport, session_id)
# Session state
self.created_at = None
self.state = "created" # created, invited, accepted, ringing, hungup
self._pipeline_started = False
# Track IDs
self.current_track_id: Optional[str] = str(uuid.uuid4())
logger.info(f"Session {self.id} created")
logger.info(f"Session {self.id} created (duplex={self.use_duplex})")
async def handle_text(self, text_data: str) -> None:
"""
@@ -112,7 +129,10 @@ class Session:
audio_bytes: PCM audio data
"""
try:
await self.pipeline.process_input(audio_bytes)
if self.use_duplex:
await self.pipeline.process_audio(audio_bytes)
else:
await self.pipeline.process_input(audio_bytes)
except Exception as e:
logger.error(f"Session {self.id} handle_audio error: {e}", exc_info=True)
@@ -128,6 +148,15 @@ class Session:
"timestamp": self._get_timestamp_ms()
})
# Start duplex pipeline if enabled
if self.use_duplex and not self._pipeline_started:
try:
await self.pipeline.start()
self._pipeline_started = True
logger.info(f"Session {self.id} duplex pipeline started")
except Exception as e:
logger.error(f"Failed to start duplex pipeline: {e}")
logger.info(f"Session {self.id} invited with codec: {option.get('codec', 'pcm')}")
async def _handle_accept(self, data: Dict[str, Any]) -> None:
@@ -199,7 +228,10 @@ class Session:
logger.info(f"Session {self.id} graceful interrupt")
else:
logger.info(f"Session {self.id} immediate interrupt")
await self.pipeline.interrupt()
if self.use_duplex:
await self.pipeline.interrupt()
else:
await self.pipeline.interrupt()
async def _handle_pause(self) -> None:
"""Handle pause command."""
@@ -236,7 +268,10 @@ class Session:
"""Handle chat command."""
logger.info(f"Session {self.id} chat: {command.text[:50]}...")
# Process text input through pipeline
await self.pipeline.process_text_input(command.text)
if self.use_duplex:
await self.pipeline.process_text(command.text)
else:
await self.pipeline.process_text_input(command.text)
async def _send_error(self, sender: str, error_message: str) -> None:
"""