Realtime Class

The Realtime component provides end-to-end speech-to-speech communication, combining STT, LLM, and TTS functionality in a single, optimized interface. It delivers ultra-low latency speech processing, direct audio streaming without intermediate text conversion, and support for multiple modalities (audio, video, text).

When to Use Realtime

Use a Realtime LLM when you want the lowest latency voice interactions. The model handles speech recognition, response generation, and speech synthesis natively—no separate STT or TTS services required.

Use the traditional STT → LLM → TTS pipeline when you need custom voices (e.g., Cartesia, ElevenLabs), specific transcription providers, or models that don’t support realtime audio.

Supported Providers

• OpenAI Realtime — WebRTC-based, supports video
• Gemini Live — WebSocket-based, supports video
• AWS Nova — WebSocket-based
• Qwen Omni — Native audio support

Basic Usage

from vision_agents.core import Agent, User
from vision_agents.plugins import openai, getstream

agent = Agent(
    edge=getstream.Edge(),
    agent_user=User(name="AI Assistant", id="agent"),
    instructions="You're a helpful voice assistant",
    llm=openai.Realtime(model="gpt-realtime", voice="marin"),
    processors=[]
)

Agent methods with realtime

await agent.simple_response("What do you see in the video?", interrupt=True)

Use agent.simple_response(...) to inject text prompts. agent.say() is not supported with Realtime LLMs — use simple_response() instead. You usually do not call realtime audio methods directly from app code.

Properties

Property	Type	Description
connected	bool	True if the realtime session is active
fps	int	Video frames per second sent to the model (default: 1)
session_id	str	UUID identifying the current session
epoch	int	Monotonic interruption counter. Increments each time interrupt() is called, allowing stale audio output events to be identified and dropped.

Realtime methods

interrupt()

Increments the epoch counter so that any in-flight audio output from a previous response is detected as stale and discarded by the Agent. The Agent calls this automatically on barge-in.

Events

The Realtime class emits a small set of events for connection state:

Event	Description
RealtimeConnectedEvent	Connection established with session config & capabilities
RealtimeDisconnectedEvent	Connection closed (includes reason and clean flag)

For conversation events, subscribe to the agent-level events — UserTranscriptEvent fires in both classic STT and realtime modes:

from vision_agents.core.agents.events import UserTranscriptEvent

@agent.events.subscribe
async def on_user_speech(event: UserTranscriptEvent):
    print(f"User said: {event.text}")

See Events Reference for the full event surface, including LLM, tool, and error events.

For provider-specific parameters and configuration, see the integration docs for OpenAI, Gemini, AWS Bedrock, or Qwen.