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Documentation Index

Fetch the complete documentation index at: https://docs.streampixel.io/llms.txt

Use this file to discover all available pages before exploring further.

SFU (Selective Forwarding Unit) lets one Unreal Engine instance stream to many viewers — one Host controls the app, everyone else watches. SFU is a platform feature, not an SDK-only capability — you can also create SFU sessions from the Sharing tab in the dashboard (where they’re called Meeting Rooms) or from a plain share URL with ?streamerId=...&sfuHost=true query params. This page covers the SDK path — programmatic control over SFU sessions for custom frontends.

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Video tutorial

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Architecture

In standard mode, each viewer gets a dedicated UE instance (1:1). With SFU:
  • One UE instance renders the content
  • The SFU server receives the stream and forwards it to multiple viewers
  • One user is the Host (can send input to UE), all others are Players/Viewers (watch-only)
There is exactly one host per SFU session. The host is the only user who can send mouse, keyboard, and other input to the Unreal Engine application.

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Roles

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Host

The host controls the UE application. There is one host per SFU session. The host can send mouse, keyboard, and other input to UE. 
await StreamPixelApplication({
  appId: 'your-project-id',
  sfuHost: 'true',
  AutoConnect: true,
});

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Player (viewer)

Players watch the stream but cannot send input to UE. Multiple players can connect simultaneously.
Players and viewers are watch-only. They cannot send any input (mouse, keyboard, touch, gamepad) to the Unreal Engine application.
await StreamPixelApplication({
  appId: 'your-project-id',
  sfuPlayer: 'true',
  AutoConnect: true,
});

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Default (neither)

When neither sfuHost nor sfuPlayer is set, the SDK uses standard 1:1 streaming.

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Configuration via URL parameters

SFU mode can also be set via URL query parameters, which is useful for sharing links: 
https://yourapp.com/PROJECT_ID?sfuHost=true
https://yourapp.com/PROJECT_ID?sfuPlayer=true
You can also target a specific streamer instance: 
https://yourapp.com/PROJECT_ID?sfuPlayer=true&streamerId=hostInstance123

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Use cases

  • Live presentations: One person presents in UE, many watch
  • Spectator mode: Players watch a game being played by the host
  • Virtual events: Stream a virtual environment to a large audience
  • Training/demos: Instructor controls the application, trainees observe
  • Cost optimization: Serve many viewers from a single UE instance

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Next steps

Communicating with Unreal Engine

Send and receive data between the web client and UE.

Voice and text chat

Add real-time voice and text chat for SFU sessions.