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

42
services/__init__.py Normal file
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"""AI Services package.
Provides ASR, LLM, TTS, and Realtime API services for voice conversation.
"""
from services.base import (
ServiceState,
ASRResult,
LLMMessage,
TTSChunk,
BaseASRService,
BaseLLMService,
BaseTTSService,
)
from services.llm import OpenAILLMService, MockLLMService
from services.tts import EdgeTTSService, MockTTSService
from services.asr import BufferedASRService, MockASRService
from services.realtime import RealtimeService, RealtimeConfig, RealtimePipeline
__all__ = [
# Base classes
"ServiceState",
"ASRResult",
"LLMMessage",
"TTSChunk",
"BaseASRService",
"BaseLLMService",
"BaseTTSService",
# LLM
"OpenAILLMService",
"MockLLMService",
# TTS
"EdgeTTSService",
"MockTTSService",
# ASR
"BufferedASRService",
"MockASRService",
# Realtime
"RealtimeService",
"RealtimeConfig",
"RealtimePipeline",
]

147
services/asr.py Normal file
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"""ASR (Automatic Speech Recognition) Service implementations.
Provides speech-to-text capabilities with streaming support.
"""
import os
import asyncio
import json
from typing import AsyncIterator, Optional
from loguru import logger
from services.base import BaseASRService, ASRResult, ServiceState
# Try to import websockets for streaming ASR
try:
import websockets
WEBSOCKETS_AVAILABLE = True
except ImportError:
WEBSOCKETS_AVAILABLE = False
class BufferedASRService(BaseASRService):
"""
Buffered ASR service that accumulates audio and provides
a simple text accumulator for use with EOU detection.
This is a lightweight implementation that works with the
existing VAD + EOU pattern without requiring external ASR.
"""
def __init__(
self,
sample_rate: int = 16000,
language: str = "en"
):
super().__init__(sample_rate=sample_rate, language=language)
self._audio_buffer: bytes = b""
self._current_text: str = ""
self._transcript_queue: asyncio.Queue[ASRResult] = asyncio.Queue()
async def connect(self) -> None:
"""No connection needed for buffered ASR."""
self.state = ServiceState.CONNECTED
logger.info("Buffered ASR service connected")
async def disconnect(self) -> None:
"""Clear buffers on disconnect."""
self._audio_buffer = b""
self._current_text = ""
self.state = ServiceState.DISCONNECTED
logger.info("Buffered ASR service disconnected")
async def send_audio(self, audio: bytes) -> None:
"""Buffer audio for later processing."""
self._audio_buffer += audio
async def receive_transcripts(self) -> AsyncIterator[ASRResult]:
"""Yield transcription results."""
while True:
try:
result = await asyncio.wait_for(
self._transcript_queue.get(),
timeout=0.1
)
yield result
except asyncio.TimeoutError:
continue
except asyncio.CancelledError:
break
def set_text(self, text: str) -> None:
"""
Set the current transcript text directly.
This allows external integration (e.g., Whisper, other ASR)
to provide transcripts.
"""
self._current_text = text
result = ASRResult(text=text, is_final=False)
asyncio.create_task(self._transcript_queue.put(result))
def get_and_clear_text(self) -> str:
"""Get accumulated text and clear buffer."""
text = self._current_text
self._current_text = ""
self._audio_buffer = b""
return text
def get_audio_buffer(self) -> bytes:
"""Get accumulated audio buffer."""
return self._audio_buffer
def clear_audio_buffer(self) -> None:
"""Clear audio buffer."""
self._audio_buffer = b""
class MockASRService(BaseASRService):
"""
Mock ASR service for testing without actual recognition.
"""
def __init__(self, sample_rate: int = 16000, language: str = "en"):
super().__init__(sample_rate=sample_rate, language=language)
self._transcript_queue: asyncio.Queue[ASRResult] = asyncio.Queue()
self._mock_texts = [
"Hello, how are you?",
"That's interesting.",
"Tell me more about that.",
"I understand.",
]
self._text_index = 0
async def connect(self) -> None:
self.state = ServiceState.CONNECTED
logger.info("Mock ASR service connected")
async def disconnect(self) -> None:
self.state = ServiceState.DISCONNECTED
logger.info("Mock ASR service disconnected")
async def send_audio(self, audio: bytes) -> None:
"""Mock audio processing - generates fake transcripts periodically."""
pass
def trigger_transcript(self) -> None:
"""Manually trigger a transcript (for testing)."""
text = self._mock_texts[self._text_index % len(self._mock_texts)]
self._text_index += 1
result = ASRResult(text=text, is_final=True, confidence=0.95)
asyncio.create_task(self._transcript_queue.put(result))
async def receive_transcripts(self) -> AsyncIterator[ASRResult]:
"""Yield transcription results."""
while True:
try:
result = await asyncio.wait_for(
self._transcript_queue.get(),
timeout=0.1
)
yield result
except asyncio.TimeoutError:
continue
except asyncio.CancelledError:
break

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services/base.py Normal file
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"""Base classes for AI services.
Defines abstract interfaces for ASR, LLM, and TTS services,
inspired by pipecat's service architecture and active-call's
StreamEngine pattern.
"""
from abc import ABC, abstractmethod
from dataclasses import dataclass, field
from typing import AsyncIterator, Optional, List, Dict, Any
from enum import Enum
class ServiceState(Enum):
"""Service connection state."""
DISCONNECTED = "disconnected"
CONNECTING = "connecting"
CONNECTED = "connected"
ERROR = "error"
@dataclass
class ASRResult:
"""ASR transcription result."""
text: str
is_final: bool = False
confidence: float = 1.0
language: Optional[str] = None
start_time: Optional[float] = None
end_time: Optional[float] = None
def __str__(self) -> str:
status = "FINAL" if self.is_final else "PARTIAL"
return f"[{status}] {self.text}"
@dataclass
class LLMMessage:
"""LLM conversation message."""
role: str # "system", "user", "assistant", "function"
content: str
name: Optional[str] = None # For function calls
function_call: Optional[Dict[str, Any]] = None
def to_dict(self) -> Dict[str, Any]:
"""Convert to API-compatible dict."""
d = {"role": self.role, "content": self.content}
if self.name:
d["name"] = self.name
if self.function_call:
d["function_call"] = self.function_call
return d
@dataclass
class TTSChunk:
"""TTS audio chunk."""
audio: bytes # PCM audio data
sample_rate: int = 16000
channels: int = 1
bits_per_sample: int = 16
is_final: bool = False
text_offset: Optional[int] = None # Character offset in original text
class BaseASRService(ABC):
"""
Abstract base class for ASR (Speech-to-Text) services.
Supports both streaming and non-streaming transcription.
"""
def __init__(self, sample_rate: int = 16000, language: str = "en"):
self.sample_rate = sample_rate
self.language = language
self.state = ServiceState.DISCONNECTED
@abstractmethod
async def connect(self) -> None:
"""Establish connection to ASR service."""
pass
@abstractmethod
async def disconnect(self) -> None:
"""Close connection to ASR service."""
pass
@abstractmethod
async def send_audio(self, audio: bytes) -> None:
"""
Send audio chunk for transcription.
Args:
audio: PCM audio data (16-bit, mono)
"""
pass
@abstractmethod
async def receive_transcripts(self) -> AsyncIterator[ASRResult]:
"""
Receive transcription results.
Yields:
ASRResult objects as they become available
"""
pass
async def transcribe(self, audio: bytes) -> ASRResult:
"""
Transcribe a complete audio buffer (non-streaming).
Args:
audio: Complete PCM audio data
Returns:
Final ASRResult
"""
# Default implementation using streaming
await self.send_audio(audio)
async for result in self.receive_transcripts():
if result.is_final:
return result
return ASRResult(text="", is_final=True)
class BaseLLMService(ABC):
"""
Abstract base class for LLM (Language Model) services.
Supports streaming responses for real-time conversation.
"""
def __init__(self, model: str = "gpt-4"):
self.model = model
self.state = ServiceState.DISCONNECTED
@abstractmethod
async def connect(self) -> None:
"""Initialize LLM service connection."""
pass
@abstractmethod
async def disconnect(self) -> None:
"""Close LLM service connection."""
pass
@abstractmethod
async def generate(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> str:
"""
Generate a complete response.
Args:
messages: Conversation history
temperature: Sampling temperature
max_tokens: Maximum tokens to generate
Returns:
Complete response text
"""
pass
@abstractmethod
async def generate_stream(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> AsyncIterator[str]:
"""
Generate response in streaming mode.
Args:
messages: Conversation history
temperature: Sampling temperature
max_tokens: Maximum tokens to generate
Yields:
Text chunks as they are generated
"""
pass
class BaseTTSService(ABC):
"""
Abstract base class for TTS (Text-to-Speech) services.
Supports streaming audio synthesis for low-latency playback.
"""
def __init__(
self,
voice: str = "default",
sample_rate: int = 16000,
speed: float = 1.0
):
self.voice = voice
self.sample_rate = sample_rate
self.speed = speed
self.state = ServiceState.DISCONNECTED
@abstractmethod
async def connect(self) -> None:
"""Initialize TTS service connection."""
pass
@abstractmethod
async def disconnect(self) -> None:
"""Close TTS service connection."""
pass
@abstractmethod
async def synthesize(self, text: str) -> bytes:
"""
Synthesize complete audio for text (non-streaming).
Args:
text: Text to synthesize
Returns:
Complete PCM audio data
"""
pass
@abstractmethod
async def synthesize_stream(self, text: str) -> AsyncIterator[TTSChunk]:
"""
Synthesize audio in streaming mode.
Args:
text: Text to synthesize
Yields:
TTSChunk objects as audio is generated
"""
pass
async def cancel(self) -> None:
"""Cancel ongoing synthesis (for barge-in support)."""
pass

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services/llm.py Normal file
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"""LLM (Large Language Model) Service implementations.
Provides OpenAI-compatible LLM integration with streaming support
for real-time voice conversation.
"""
import os
import asyncio
from typing import AsyncIterator, Optional, List, Dict, Any
from loguru import logger
from services.base import BaseLLMService, LLMMessage, ServiceState
# Try to import openai
try:
from openai import AsyncOpenAI
OPENAI_AVAILABLE = True
except ImportError:
OPENAI_AVAILABLE = False
logger.warning("openai package not available - LLM service will be disabled")
class OpenAILLMService(BaseLLMService):
"""
OpenAI-compatible LLM service.
Supports streaming responses for low-latency voice conversation.
Works with OpenAI API, Azure OpenAI, and compatible APIs.
"""
def __init__(
self,
model: str = "gpt-4o-mini",
api_key: Optional[str] = None,
base_url: Optional[str] = None,
system_prompt: Optional[str] = None
):
"""
Initialize OpenAI LLM service.
Args:
model: Model name (e.g., "gpt-4o-mini", "gpt-4o")
api_key: OpenAI API key (defaults to OPENAI_API_KEY env var)
base_url: Custom API base URL (for Azure or compatible APIs)
system_prompt: Default system prompt for conversations
"""
super().__init__(model=model)
self.api_key = api_key or os.getenv("OPENAI_API_KEY")
self.base_url = base_url or os.getenv("OPENAI_API_URL")
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."
)
self.client: Optional[AsyncOpenAI] = None
self._cancel_event = asyncio.Event()
async def connect(self) -> None:
"""Initialize OpenAI client."""
if not OPENAI_AVAILABLE:
raise RuntimeError("openai package not installed")
if not self.api_key:
raise ValueError("OpenAI API key not provided")
self.client = AsyncOpenAI(
api_key=self.api_key,
base_url=self.base_url
)
self.state = ServiceState.CONNECTED
logger.info(f"OpenAI LLM service connected: model={self.model}")
async def disconnect(self) -> None:
"""Close OpenAI client."""
if self.client:
await self.client.close()
self.client = None
self.state = ServiceState.DISCONNECTED
logger.info("OpenAI LLM service disconnected")
def _prepare_messages(self, messages: List[LLMMessage]) -> List[Dict[str, Any]]:
"""Prepare messages list with system prompt."""
result = []
# Add system prompt if not already present
has_system = any(m.role == "system" for m in messages)
if not has_system and self.system_prompt:
result.append({"role": "system", "content": self.system_prompt})
# Add all messages
for msg in messages:
result.append(msg.to_dict())
return result
async def generate(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> str:
"""
Generate a complete response.
Args:
messages: Conversation history
temperature: Sampling temperature
max_tokens: Maximum tokens to generate
Returns:
Complete response text
"""
if not self.client:
raise RuntimeError("LLM service not connected")
prepared = self._prepare_messages(messages)
try:
response = await self.client.chat.completions.create(
model=self.model,
messages=prepared,
temperature=temperature,
max_tokens=max_tokens
)
content = response.choices[0].message.content or ""
logger.debug(f"LLM response: {content[:100]}...")
return content
except Exception as e:
logger.error(f"LLM generation error: {e}")
raise
async def generate_stream(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> AsyncIterator[str]:
"""
Generate response in streaming mode.
Args:
messages: Conversation history
temperature: Sampling temperature
max_tokens: Maximum tokens to generate
Yields:
Text chunks as they are generated
"""
if not self.client:
raise RuntimeError("LLM service not connected")
prepared = self._prepare_messages(messages)
self._cancel_event.clear()
try:
stream = await self.client.chat.completions.create(
model=self.model,
messages=prepared,
temperature=temperature,
max_tokens=max_tokens,
stream=True
)
async for chunk in stream:
# Check for cancellation
if self._cancel_event.is_set():
logger.info("LLM stream cancelled")
break
if chunk.choices and chunk.choices[0].delta.content:
content = chunk.choices[0].delta.content
yield content
except asyncio.CancelledError:
logger.info("LLM stream cancelled via asyncio")
raise
except Exception as e:
logger.error(f"LLM streaming error: {e}")
raise
def cancel(self) -> None:
"""Cancel ongoing generation."""
self._cancel_event.set()
class MockLLMService(BaseLLMService):
"""
Mock LLM service for testing without API calls.
"""
def __init__(self, response_delay: float = 0.5):
super().__init__(model="mock")
self.response_delay = response_delay
self.responses = [
"Hello! How can I help you today?",
"That's an interesting question. Let me think about it.",
"I understand. Is there anything else you'd like to know?",
"Great! I'm here if you need anything else.",
]
self._response_index = 0
async def connect(self) -> None:
self.state = ServiceState.CONNECTED
logger.info("Mock LLM service connected")
async def disconnect(self) -> None:
self.state = ServiceState.DISCONNECTED
logger.info("Mock LLM service disconnected")
async def generate(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> str:
await asyncio.sleep(self.response_delay)
response = self.responses[self._response_index % len(self.responses)]
self._response_index += 1
return response
async def generate_stream(
self,
messages: List[LLMMessage],
temperature: float = 0.7,
max_tokens: Optional[int] = None
) -> AsyncIterator[str]:
response = await self.generate(messages, temperature, max_tokens)
# Stream word by word
words = response.split()
for i, word in enumerate(words):
if i > 0:
yield " "
yield word
await asyncio.sleep(0.05) # Simulate streaming delay

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services/realtime.py Normal file
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"""OpenAI Realtime API Service.
Provides true duplex voice conversation using OpenAI's Realtime API,
similar to active-call's RealtimeProcessor. This bypasses the need for
separate ASR/LLM/TTS services by handling everything server-side.
The Realtime API provides:
- Server-side VAD with turn detection
- Streaming speech-to-text
- Streaming LLM responses
- Streaming text-to-speech
- Function calling support
- Barge-in/interruption handling
"""
import os
import asyncio
import json
import base64
from typing import Optional, Dict, Any, Callable, Awaitable, List
from dataclasses import dataclass, field
from enum import Enum
from loguru import logger
try:
import websockets
WEBSOCKETS_AVAILABLE = True
except ImportError:
WEBSOCKETS_AVAILABLE = False
logger.warning("websockets not available - Realtime API will be disabled")
class RealtimeState(Enum):
"""Realtime API connection state."""
DISCONNECTED = "disconnected"
CONNECTING = "connecting"
CONNECTED = "connected"
ERROR = "error"
@dataclass
class RealtimeConfig:
"""Configuration for OpenAI Realtime API."""
# API Configuration
api_key: Optional[str] = None
model: str = "gpt-4o-realtime-preview"
endpoint: Optional[str] = None # For Azure or custom endpoints
# Voice Configuration
voice: str = "alloy" # alloy, echo, shimmer, etc.
instructions: str = (
"You are a helpful, friendly voice assistant. "
"Keep your responses concise and conversational."
)
# Turn Detection (Server-side VAD)
turn_detection: Optional[Dict[str, Any]] = field(default_factory=lambda: {
"type": "server_vad",
"threshold": 0.5,
"prefix_padding_ms": 300,
"silence_duration_ms": 500
})
# Audio Configuration
input_audio_format: str = "pcm16"
output_audio_format: str = "pcm16"
# Tools/Functions
tools: List[Dict[str, Any]] = field(default_factory=list)
class RealtimeService:
"""
OpenAI Realtime API service for true duplex voice conversation.
This service handles the entire voice conversation pipeline:
1. Audio input → Server-side VAD → Speech-to-text
2. Text → LLM processing → Response generation
3. Response → Text-to-speech → Audio output
Events emitted:
- on_audio: Audio output from the assistant
- on_transcript: Text transcript (user or assistant)
- on_speech_started: User started speaking
- on_speech_stopped: User stopped speaking
- on_response_started: Assistant started responding
- on_response_done: Assistant finished responding
- on_function_call: Function call requested
- on_error: Error occurred
"""
def __init__(self, config: Optional[RealtimeConfig] = None):
"""
Initialize Realtime API service.
Args:
config: Realtime configuration (uses defaults if not provided)
"""
self.config = config or RealtimeConfig()
self.config.api_key = self.config.api_key or os.getenv("OPENAI_API_KEY")
self.state = RealtimeState.DISCONNECTED
self._ws = None
self._receive_task: Optional[asyncio.Task] = None
self._cancel_event = asyncio.Event()
# Event callbacks
self._callbacks: Dict[str, List[Callable]] = {
"on_audio": [],
"on_transcript": [],
"on_speech_started": [],
"on_speech_stopped": [],
"on_response_started": [],
"on_response_done": [],
"on_function_call": [],
"on_error": [],
"on_interrupted": [],
}
logger.debug(f"RealtimeService initialized with model={self.config.model}")
def on(self, event: str, callback: Callable[..., Awaitable[None]]) -> None:
"""
Register event callback.
Args:
event: Event name
callback: Async callback function
"""
if event in self._callbacks:
self._callbacks[event].append(callback)
async def _emit(self, event: str, *args, **kwargs) -> None:
"""Emit event to all registered callbacks."""
for callback in self._callbacks.get(event, []):
try:
await callback(*args, **kwargs)
except Exception as e:
logger.error(f"Event callback error ({event}): {e}")
async def connect(self) -> None:
"""Connect to OpenAI Realtime API."""
if not WEBSOCKETS_AVAILABLE:
raise RuntimeError("websockets package not installed")
if not self.config.api_key:
raise ValueError("OpenAI API key not provided")
self.state = RealtimeState.CONNECTING
# Build URL
if self.config.endpoint:
# Azure or custom endpoint
url = f"{self.config.endpoint}/openai/realtime?api-version=2024-10-01-preview&deployment={self.config.model}"
else:
# OpenAI endpoint
url = f"wss://api.openai.com/v1/realtime?model={self.config.model}"
# Build headers
headers = {}
if self.config.endpoint:
headers["api-key"] = self.config.api_key
else:
headers["Authorization"] = f"Bearer {self.config.api_key}"
headers["OpenAI-Beta"] = "realtime=v1"
try:
logger.info(f"Connecting to Realtime API: {url}")
self._ws = await websockets.connect(url, extra_headers=headers)
# Send session configuration
await self._configure_session()
# Start receive loop
self._receive_task = asyncio.create_task(self._receive_loop())
self.state = RealtimeState.CONNECTED
logger.info("Realtime API connected successfully")
except Exception as e:
self.state = RealtimeState.ERROR
logger.error(f"Realtime API connection failed: {e}")
raise
async def _configure_session(self) -> None:
"""Send session configuration to server."""
session_config = {
"type": "session.update",
"session": {
"modalities": ["text", "audio"],
"instructions": self.config.instructions,
"voice": self.config.voice,
"input_audio_format": self.config.input_audio_format,
"output_audio_format": self.config.output_audio_format,
"turn_detection": self.config.turn_detection,
}
}
if self.config.tools:
session_config["session"]["tools"] = self.config.tools
await self._send(session_config)
logger.debug("Session configuration sent")
async def _send(self, data: Dict[str, Any]) -> None:
"""Send JSON data to server."""
if self._ws:
await self._ws.send(json.dumps(data))
async def send_audio(self, audio_bytes: bytes) -> None:
"""
Send audio to the Realtime API.
Args:
audio_bytes: PCM audio data (16-bit, mono, 24kHz by default)
"""
if self.state != RealtimeState.CONNECTED:
return
# Encode audio as base64
audio_b64 = base64.standard_b64encode(audio_bytes).decode()
await self._send({
"type": "input_audio_buffer.append",
"audio": audio_b64
})
async def send_text(self, text: str) -> None:
"""
Send text input (bypassing audio).
Args:
text: User text input
"""
if self.state != RealtimeState.CONNECTED:
return
# Create a conversation item with user text
await self._send({
"type": "conversation.item.create",
"item": {
"type": "message",
"role": "user",
"content": [{"type": "input_text", "text": text}]
}
})
# Trigger response
await self._send({"type": "response.create"})
async def cancel_response(self) -> None:
"""Cancel the current response (for barge-in)."""
if self.state != RealtimeState.CONNECTED:
return
await self._send({"type": "response.cancel"})
logger.debug("Response cancelled")
async def commit_audio(self) -> None:
"""Commit the audio buffer and trigger response."""
if self.state != RealtimeState.CONNECTED:
return
await self._send({"type": "input_audio_buffer.commit"})
await self._send({"type": "response.create"})
async def clear_audio_buffer(self) -> None:
"""Clear the input audio buffer."""
if self.state != RealtimeState.CONNECTED:
return
await self._send({"type": "input_audio_buffer.clear"})
async def submit_function_result(self, call_id: str, result: str) -> None:
"""
Submit function call result.
Args:
call_id: The function call ID
result: JSON string result
"""
if self.state != RealtimeState.CONNECTED:
return
await self._send({
"type": "conversation.item.create",
"item": {
"type": "function_call_output",
"call_id": call_id,
"output": result
}
})
# Trigger response with the function result
await self._send({"type": "response.create"})
async def _receive_loop(self) -> None:
"""Receive and process messages from the Realtime API."""
if not self._ws:
return
try:
async for message in self._ws:
try:
data = json.loads(message)
await self._handle_event(data)
except json.JSONDecodeError:
logger.warning(f"Invalid JSON received: {message[:100]}")
except asyncio.CancelledError:
logger.debug("Receive loop cancelled")
except websockets.ConnectionClosed as e:
logger.info(f"WebSocket closed: {e}")
self.state = RealtimeState.DISCONNECTED
except Exception as e:
logger.error(f"Receive loop error: {e}")
self.state = RealtimeState.ERROR
async def _handle_event(self, data: Dict[str, Any]) -> None:
"""Handle incoming event from Realtime API."""
event_type = data.get("type", "unknown")
# Audio delta - streaming audio output
if event_type == "response.audio.delta":
if "delta" in data:
audio_bytes = base64.standard_b64decode(data["delta"])
await self._emit("on_audio", audio_bytes)
# Audio transcript delta - streaming text
elif event_type == "response.audio_transcript.delta":
if "delta" in data:
await self._emit("on_transcript", data["delta"], "assistant", False)
# Audio transcript done
elif event_type == "response.audio_transcript.done":
if "transcript" in data:
await self._emit("on_transcript", data["transcript"], "assistant", True)
# Input audio transcript (user speech)
elif event_type == "conversation.item.input_audio_transcription.completed":
if "transcript" in data:
await self._emit("on_transcript", data["transcript"], "user", True)
# Speech started (server VAD detected speech)
elif event_type == "input_audio_buffer.speech_started":
await self._emit("on_speech_started", data.get("audio_start_ms", 0))
# Speech stopped
elif event_type == "input_audio_buffer.speech_stopped":
await self._emit("on_speech_stopped", data.get("audio_end_ms", 0))
# Response started
elif event_type == "response.created":
await self._emit("on_response_started", data.get("response", {}))
# Response done
elif event_type == "response.done":
await self._emit("on_response_done", data.get("response", {}))
# Function call
elif event_type == "response.function_call_arguments.done":
call_id = data.get("call_id")
name = data.get("name")
arguments = data.get("arguments", "{}")
await self._emit("on_function_call", call_id, name, arguments)
# Error
elif event_type == "error":
error = data.get("error", {})
logger.error(f"Realtime API error: {error}")
await self._emit("on_error", error)
# Session events
elif event_type == "session.created":
logger.info("Session created")
elif event_type == "session.updated":
logger.debug("Session updated")
else:
logger.debug(f"Unhandled event type: {event_type}")
async def disconnect(self) -> None:
"""Disconnect from Realtime API."""
self._cancel_event.set()
if self._receive_task:
self._receive_task.cancel()
try:
await self._receive_task
except asyncio.CancelledError:
pass
if self._ws:
await self._ws.close()
self._ws = None
self.state = RealtimeState.DISCONNECTED
logger.info("Realtime API disconnected")
class RealtimePipeline:
"""
Pipeline adapter for RealtimeService.
Provides a compatible interface with DuplexPipeline but uses
OpenAI Realtime API for all processing.
"""
def __init__(
self,
transport,
session_id: str,
config: Optional[RealtimeConfig] = None
):
"""
Initialize Realtime pipeline.
Args:
transport: Transport for sending audio/events
session_id: Session identifier
config: Realtime configuration
"""
self.transport = transport
self.session_id = session_id
self.service = RealtimeService(config)
# Register callbacks
self.service.on("on_audio", self._on_audio)
self.service.on("on_transcript", self._on_transcript)
self.service.on("on_speech_started", self._on_speech_started)
self.service.on("on_speech_stopped", self._on_speech_stopped)
self.service.on("on_response_started", self._on_response_started)
self.service.on("on_response_done", self._on_response_done)
self.service.on("on_error", self._on_error)
self._is_speaking = False
self._running = True
logger.info(f"RealtimePipeline initialized for session {session_id}")
async def start(self) -> None:
"""Start the pipeline."""
await self.service.connect()
async def process_audio(self, pcm_bytes: bytes) -> None:
"""
Process incoming audio.
Note: Realtime API expects 24kHz audio by default.
You may need to resample from 16kHz.
"""
if not self._running:
return
# TODO: Resample from 16kHz to 24kHz if needed
await self.service.send_audio(pcm_bytes)
async def process_text(self, text: str) -> None:
"""Process text input."""
if not self._running:
return
await self.service.send_text(text)
async def interrupt(self) -> None:
"""Interrupt current response."""
await self.service.cancel_response()
await self.transport.send_event({
"event": "interrupt",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
async def cleanup(self) -> None:
"""Cleanup resources."""
self._running = False
await self.service.disconnect()
# Event handlers
async def _on_audio(self, audio_bytes: bytes) -> None:
"""Handle audio output."""
await self.transport.send_audio(audio_bytes)
async def _on_transcript(self, text: str, role: str, is_final: bool) -> None:
"""Handle transcript."""
logger.info(f"[{role.upper()}] {text[:50]}..." if len(text) > 50 else f"[{role.upper()}] {text}")
async def _on_speech_started(self, start_ms: int) -> None:
"""Handle user speech start."""
self._is_speaking = True
await self.transport.send_event({
"event": "speaking",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms(),
"startTime": start_ms
})
# Cancel any ongoing response (barge-in)
await self.service.cancel_response()
async def _on_speech_stopped(self, end_ms: int) -> None:
"""Handle user speech stop."""
self._is_speaking = False
await self.transport.send_event({
"event": "silence",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms(),
"duration": end_ms
})
async def _on_response_started(self, response: Dict) -> None:
"""Handle response start."""
await self.transport.send_event({
"event": "trackStart",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
async def _on_response_done(self, response: Dict) -> None:
"""Handle response complete."""
await self.transport.send_event({
"event": "trackEnd",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms()
})
async def _on_error(self, error: Dict) -> None:
"""Handle error."""
await self.transport.send_event({
"event": "error",
"trackId": self.session_id,
"timestamp": self._get_timestamp_ms(),
"sender": "realtime",
"error": str(error)
})
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 user is speaking."""
return self._is_speaking

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"""SiliconFlow TTS Service with streaming support.
Uses SiliconFlow's CosyVoice2 or MOSS-TTSD models for low-latency
text-to-speech synthesis with streaming.
API Docs: https://docs.siliconflow.cn/cn/api-reference/audio/create-speech
"""
import os
import asyncio
import aiohttp
from typing import AsyncIterator, Optional
from loguru import logger
from services.base import BaseTTSService, TTSChunk, ServiceState
class SiliconFlowTTSService(BaseTTSService):
"""
SiliconFlow TTS service with streaming support.
Supports CosyVoice2-0.5B and MOSS-TTSD-v0.5 models.
"""
# Available voices
VOICES = {
"alex": "FunAudioLLM/CosyVoice2-0.5B:alex",
"anna": "FunAudioLLM/CosyVoice2-0.5B:anna",
"bella": "FunAudioLLM/CosyVoice2-0.5B:bella",
"benjamin": "FunAudioLLM/CosyVoice2-0.5B:benjamin",
"charles": "FunAudioLLM/CosyVoice2-0.5B:charles",
"claire": "FunAudioLLM/CosyVoice2-0.5B:claire",
"david": "FunAudioLLM/CosyVoice2-0.5B:david",
"diana": "FunAudioLLM/CosyVoice2-0.5B:diana",
}
def __init__(
self,
api_key: Optional[str] = None,
voice: str = "anna",
model: str = "FunAudioLLM/CosyVoice2-0.5B",
sample_rate: int = 16000,
speed: float = 1.0
):
"""
Initialize SiliconFlow TTS service.
Args:
api_key: SiliconFlow API key (defaults to SILICONFLOW_API_KEY env var)
voice: Voice name (alex, anna, bella, benjamin, charles, claire, david, diana)
model: Model name
sample_rate: Output sample rate (8000, 16000, 24000, 32000, 44100)
speed: Speech speed (0.25 to 4.0)
"""
# Resolve voice name
if voice in self.VOICES:
full_voice = self.VOICES[voice]
else:
full_voice = voice
super().__init__(voice=full_voice, sample_rate=sample_rate, speed=speed)
self.api_key = api_key or os.getenv("SILICONFLOW_API_KEY")
self.model = model
self.api_url = "https://api.siliconflow.cn/v1/audio/speech"
self._session: Optional[aiohttp.ClientSession] = None
self._cancel_event = asyncio.Event()
async def connect(self) -> None:
"""Initialize HTTP session."""
if not self.api_key:
raise ValueError("SiliconFlow API key not provided. Set SILICONFLOW_API_KEY env var.")
self._session = aiohttp.ClientSession(
headers={
"Authorization": f"Bearer {self.api_key}",
"Content-Type": "application/json"
}
)
self.state = ServiceState.CONNECTED
logger.info(f"SiliconFlow TTS service ready: voice={self.voice}, model={self.model}")
async def disconnect(self) -> None:
"""Close HTTP session."""
if self._session:
await self._session.close()
self._session = None
self.state = ServiceState.DISCONNECTED
logger.info("SiliconFlow TTS service disconnected")
async def synthesize(self, text: str) -> bytes:
"""Synthesize complete audio for text."""
audio_data = b""
async for chunk in self.synthesize_stream(text):
audio_data += chunk.audio
return audio_data
async def synthesize_stream(self, text: str) -> AsyncIterator[TTSChunk]:
"""
Synthesize audio in streaming mode.
Args:
text: Text to synthesize
Yields:
TTSChunk objects with PCM audio
"""
if not self._session:
raise RuntimeError("TTS service not connected")
if not text.strip():
return
self._cancel_event.clear()
payload = {
"model": self.model,
"input": text,
"voice": self.voice,
"response_format": "pcm",
"sample_rate": self.sample_rate,
"stream": True,
"speed": self.speed
}
try:
async with self._session.post(self.api_url, json=payload) as response:
if response.status != 200:
error_text = await response.text()
logger.error(f"SiliconFlow TTS error: {response.status} - {error_text}")
return
# Stream audio chunks
chunk_size = self.sample_rate * 2 // 10 # 100ms chunks
buffer = b""
async for chunk in response.content.iter_any():
if self._cancel_event.is_set():
logger.info("TTS synthesis cancelled")
return
buffer += chunk
# Yield complete chunks
while len(buffer) >= chunk_size:
audio_chunk = buffer[:chunk_size]
buffer = buffer[chunk_size:]
yield TTSChunk(
audio=audio_chunk,
sample_rate=self.sample_rate,
is_final=False
)
# Yield remaining buffer
if buffer:
yield TTSChunk(
audio=buffer,
sample_rate=self.sample_rate,
is_final=True
)
except asyncio.CancelledError:
logger.info("TTS synthesis cancelled via asyncio")
raise
except Exception as e:
logger.error(f"TTS synthesis error: {e}")
raise
async def cancel(self) -> None:
"""Cancel ongoing synthesis."""
self._cancel_event.set()
class StreamingTTSAdapter:
"""
Adapter for streaming LLM text to TTS with sentence-level chunking.
This reduces latency by starting TTS as soon as a complete sentence
is received from the LLM, rather than waiting for the full response.
"""
# Sentence delimiters
SENTENCE_ENDS = {'.', '!', '?', '', '', '', '', '\n'}
def __init__(self, tts_service: BaseTTSService, transport, session_id: str):
self.tts_service = tts_service
self.transport = transport
self.session_id = session_id
self._buffer = ""
self._cancel_event = asyncio.Event()
self._is_speaking = False
async def process_text_chunk(self, text_chunk: str) -> None:
"""
Process a text chunk from LLM and trigger TTS when sentence is complete.
Args:
text_chunk: Text chunk from LLM streaming
"""
if self._cancel_event.is_set():
return
self._buffer += text_chunk
# Check for sentence completion
for i, char in enumerate(self._buffer):
if char in self.SENTENCE_ENDS:
# Found sentence end, synthesize up to this point
sentence = self._buffer[:i+1].strip()
self._buffer = self._buffer[i+1:]
if sentence:
await self._speak_sentence(sentence)
break
async def flush(self) -> None:
"""Flush remaining buffer."""
if self._buffer.strip() and not self._cancel_event.is_set():
await self._speak_sentence(self._buffer.strip())
self._buffer = ""
async def _speak_sentence(self, text: str) -> None:
"""Synthesize and send a sentence."""
if not text or self._cancel_event.is_set():
return
self._is_speaking = True
try:
async for chunk in self.tts_service.synthesize_stream(text):
if self._cancel_event.is_set():
break
await self.transport.send_audio(chunk.audio)
await asyncio.sleep(0.01) # Prevent flooding
except Exception as e:
logger.error(f"TTS speak error: {e}")
finally:
self._is_speaking = False
def cancel(self) -> None:
"""Cancel ongoing speech."""
self._cancel_event.set()
self._buffer = ""
def reset(self) -> None:
"""Reset for new turn."""
self._cancel_event.clear()
self._buffer = ""
self._is_speaking = False
@property
def is_speaking(self) -> bool:
return self._is_speaking

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"""TTS (Text-to-Speech) Service implementations.
Provides multiple TTS backend options including edge-tts (free)
and placeholder for cloud services.
"""
import os
import io
import asyncio
import struct
from typing import AsyncIterator, Optional
from loguru import logger
from services.base import BaseTTSService, TTSChunk, ServiceState
# Try to import edge-tts
try:
import edge_tts
EDGE_TTS_AVAILABLE = True
except ImportError:
EDGE_TTS_AVAILABLE = False
logger.warning("edge-tts not available - EdgeTTS service will be disabled")
class EdgeTTSService(BaseTTSService):
"""
Microsoft Edge TTS service.
Uses edge-tts library for free, high-quality speech synthesis.
Supports streaming for low-latency playback.
"""
# Voice mapping for common languages
VOICE_MAP = {
"en": "en-US-JennyNeural",
"en-US": "en-US-JennyNeural",
"en-GB": "en-GB-SoniaNeural",
"zh": "zh-CN-XiaoxiaoNeural",
"zh-CN": "zh-CN-XiaoxiaoNeural",
"zh-TW": "zh-TW-HsiaoChenNeural",
"ja": "ja-JP-NanamiNeural",
"ko": "ko-KR-SunHiNeural",
"fr": "fr-FR-DeniseNeural",
"de": "de-DE-KatjaNeural",
"es": "es-ES-ElviraNeural",
}
def __init__(
self,
voice: str = "en-US-JennyNeural",
sample_rate: int = 16000,
speed: float = 1.0
):
"""
Initialize Edge TTS service.
Args:
voice: Voice name (e.g., "en-US-JennyNeural") or language code (e.g., "en")
sample_rate: Target sample rate (will be resampled)
speed: Speech speed multiplier
"""
# Resolve voice from language code if needed
if voice in self.VOICE_MAP:
voice = self.VOICE_MAP[voice]
super().__init__(voice=voice, sample_rate=sample_rate, speed=speed)
self._cancel_event = asyncio.Event()
async def connect(self) -> None:
"""Edge TTS doesn't require explicit connection."""
if not EDGE_TTS_AVAILABLE:
raise RuntimeError("edge-tts package not installed")
self.state = ServiceState.CONNECTED
logger.info(f"Edge TTS service ready: voice={self.voice}")
async def disconnect(self) -> None:
"""Edge TTS doesn't require explicit disconnection."""
self.state = ServiceState.DISCONNECTED
logger.info("Edge TTS service disconnected")
def _get_rate_string(self) -> str:
"""Convert speed to rate string for edge-tts."""
# edge-tts uses percentage format: "+0%", "-10%", "+20%"
percentage = int((self.speed - 1.0) * 100)
if percentage >= 0:
return f"+{percentage}%"
return f"{percentage}%"
async def synthesize(self, text: str) -> bytes:
"""
Synthesize complete audio for text.
Args:
text: Text to synthesize
Returns:
PCM audio data (16-bit, mono, 16kHz)
"""
if not EDGE_TTS_AVAILABLE:
raise RuntimeError("edge-tts not available")
# Collect all chunks
audio_data = b""
async for chunk in self.synthesize_stream(text):
audio_data += chunk.audio
return audio_data
async def synthesize_stream(self, text: str) -> AsyncIterator[TTSChunk]:
"""
Synthesize audio in streaming mode.
Args:
text: Text to synthesize
Yields:
TTSChunk objects with PCM audio
"""
if not EDGE_TTS_AVAILABLE:
raise RuntimeError("edge-tts not available")
self._cancel_event.clear()
try:
communicate = edge_tts.Communicate(
text,
voice=self.voice,
rate=self._get_rate_string()
)
# edge-tts outputs MP3, we need to decode to PCM
# For now, collect MP3 chunks and yield after conversion
mp3_data = b""
async for chunk in communicate.stream():
# Check for cancellation
if self._cancel_event.is_set():
logger.info("TTS synthesis cancelled")
return
if chunk["type"] == "audio":
mp3_data += chunk["data"]
# Convert MP3 to PCM
if mp3_data:
pcm_data = await self._convert_mp3_to_pcm(mp3_data)
if pcm_data:
# Yield in chunks for streaming playback
chunk_size = self.sample_rate * 2 // 10 # 100ms chunks
for i in range(0, len(pcm_data), chunk_size):
if self._cancel_event.is_set():
return
chunk_data = pcm_data[i:i + chunk_size]
yield TTSChunk(
audio=chunk_data,
sample_rate=self.sample_rate,
is_final=(i + chunk_size >= len(pcm_data))
)
except asyncio.CancelledError:
logger.info("TTS synthesis cancelled via asyncio")
raise
except Exception as e:
logger.error(f"TTS synthesis error: {e}")
raise
async def _convert_mp3_to_pcm(self, mp3_data: bytes) -> bytes:
"""
Convert MP3 audio to PCM.
Uses pydub or ffmpeg for conversion.
"""
try:
# Try using pydub (requires ffmpeg)
from pydub import AudioSegment
# Load MP3 from bytes
audio = AudioSegment.from_mp3(io.BytesIO(mp3_data))
# Convert to target format
audio = audio.set_frame_rate(self.sample_rate)
audio = audio.set_channels(1)
audio = audio.set_sample_width(2) # 16-bit
# Export as raw PCM
return audio.raw_data
except ImportError:
logger.warning("pydub not available, trying fallback")
# Fallback: Use subprocess to call ffmpeg directly
return await self._ffmpeg_convert(mp3_data)
except Exception as e:
logger.error(f"Audio conversion error: {e}")
return b""
async def _ffmpeg_convert(self, mp3_data: bytes) -> bytes:
"""Convert MP3 to PCM using ffmpeg subprocess."""
try:
process = await asyncio.create_subprocess_exec(
"ffmpeg",
"-i", "pipe:0",
"-f", "s16le",
"-acodec", "pcm_s16le",
"-ar", str(self.sample_rate),
"-ac", "1",
"pipe:1",
stdin=asyncio.subprocess.PIPE,
stdout=asyncio.subprocess.PIPE,
stderr=asyncio.subprocess.DEVNULL
)
stdout, _ = await process.communicate(input=mp3_data)
return stdout
except Exception as e:
logger.error(f"ffmpeg conversion error: {e}")
return b""
async def cancel(self) -> None:
"""Cancel ongoing synthesis."""
self._cancel_event.set()
class MockTTSService(BaseTTSService):
"""
Mock TTS service for testing without actual synthesis.
Generates silence or simple tones.
"""
def __init__(
self,
voice: str = "mock",
sample_rate: int = 16000,
speed: float = 1.0
):
super().__init__(voice=voice, sample_rate=sample_rate, speed=speed)
async def connect(self) -> None:
self.state = ServiceState.CONNECTED
logger.info("Mock TTS service connected")
async def disconnect(self) -> None:
self.state = ServiceState.DISCONNECTED
logger.info("Mock TTS service disconnected")
async def synthesize(self, text: str) -> bytes:
"""Generate silence based on text length."""
# Approximate: 100ms per word
word_count = len(text.split())
duration_ms = word_count * 100
samples = int(self.sample_rate * duration_ms / 1000)
# Generate silence (zeros)
return bytes(samples * 2) # 16-bit = 2 bytes per sample
async def synthesize_stream(self, text: str) -> AsyncIterator[TTSChunk]:
"""Generate silence chunks."""
audio = await self.synthesize(text)
# Yield in 100ms chunks
chunk_size = self.sample_rate * 2 // 10
for i in range(0, len(audio), chunk_size):
chunk_data = audio[i:i + chunk_size]
yield TTSChunk(
audio=chunk_data,
sample_rate=self.sample_rate,
is_final=(i + chunk_size >= len(audio))
)
await asyncio.sleep(0.05) # Simulate processing time