65d8aa2847
There are two very very edge case scenarios this is triyng to address. Scenario 1: ----------- - both pA and pB migrating - pA migrates first and subscribes to pB via remote track of pB - while the above subscribe is happening, pB also migrates and closes the remote track - by the time the subscribe set up completes, it realises that the remote track is not open any more and removes itself as subscriber - but that removal is using the wrong `isExpectedToResume` as clearing all receivers has not run yet which is what caches the `isExpectedToResume`. - That meant, the down track transceiver is not cached and hence not re-used when re-subscribing via pB's local track - Fix it by caching the expected to resume when changing receiver state to `closing`. Scenario 2: ----------- - both pA and pB migrating - pA migrates first and subscribes to pB via remote track of pB - while the above subscribe is happening, pB also migrates and closes the remote track - pB's local track is published before the remote track can be fully closed and all the subscribers removed. That local track gets added to track manager. - While the remote track is cleaning, subscription manager triggers again to for pA to subscribe to pB's track. The track manager now resolves to the local track. - Local track subscription progresses. As the remote track clean up is not finished, the transceiver is not cached. So, the local track based subscription creates a new transceiver and that ends up causing duplicate tracks in the SDP offer. - Fix it by creating a FIFO in track manager and only resolve using the first one. So, in the above case, till the remote track is fully cleaned up, the track manager will resolve to that. Yes, the subscriptions itself will fail as the track is not in open state (i. e. it might be in `closing` state), but that is fine as subscription manager will eventually resolve to the local track and proper transceiver re-use can happen.
LiveKit: Real-time video, audio and data for developers
LiveKit is an open source project that provides scalable, multi-user conferencing based on WebRTC. It's designed to provide everything you need to build real-time video audio data capabilities in your applications.
LiveKit's server is written in Go, using the awesome Pion WebRTC implementation.
Features
- Scalable, distributed WebRTC SFU (Selective Forwarding Unit)
- Modern, full-featured client SDKs
- Built for production, supports JWT authentication
- Robust networking and connectivity, UDP/TCP/TURN
- Easy to deploy: single binary, Docker or Kubernetes
- Advanced features including:
- speaker detection
- simulcast
- end-to-end optimizations
- selective subscription
- moderation APIs
- end-to-end encryption
- SVC codecs (VP9, AV1)
- webhooks
- distributed and multi-region
Documentation & Guides
Live Demos
- LiveKit Meet (source)
- Spatial Audio (source)
- Livestreaming from OBS Studio (source)
- AI voice assistant using ChatGPT (source)
Ecosystem
- Agents: build real-time multimodal AI applications with programmable backend participants
- Egress: record or multi-stream rooms and export individual tracks
- Ingress: ingest streams from external sources like RTMP, WHIP, HLS, or OBS Studio
SDKs & Tools
Client SDKs
Client SDKs enable your frontend to include interactive, multi-user experiences.
| Language | Repo | Declarative UI | Links |
|---|---|---|---|
| JavaScript (TypeScript) | client-sdk-js | React | docs | JS example | React example |
| Swift (iOS / MacOS) | client-sdk-swift | Swift UI | docs | example |
| Kotlin (Android) | client-sdk-android | Compose | docs | example | Compose example |
| Flutter (all platforms) | client-sdk-flutter | native | docs | example |
| Unity WebGL | client-sdk-unity-web | docs | |
| React Native (beta) | client-sdk-react-native | native | |
| Rust | client-sdk-rust |
Server SDKs
Server SDKs enable your backend to generate access tokens, call server APIs, and receive webhooks. In addition, the Go SDK includes client capabilities, enabling you to build automations that behave like end-users.
| Language | Repo | Docs |
|---|---|---|
| Go | server-sdk-go | docs |
| JavaScript (TypeScript) | server-sdk-js | docs |
| Ruby | server-sdk-ruby | |
| Java (Kotlin) | server-sdk-kotlin | |
| Python (community) | python-sdks | |
| PHP (community) | agence104/livekit-server-sdk-php |
Tools
- CLI - command line interface & load tester
- Docker image
- Helm charts
Install
Tip
We recommend installing LiveKit CLI along with the server. It lets you access server APIs, create tokens, and generate test traffic.
The following will install LiveKit's media server:
MacOS
brew install livekit
Linux
curl -sSL https://get.livekit.io | bash
Windows
Download the latest release here
Getting Started
Starting LiveKit
Start LiveKit in development mode by running livekit-server --dev. It'll use a placeholder API key/secret pair.
API Key: devkey
API Secret: secret
To customize your setup for production, refer to our deployment docs
Creating access token
A user connecting to a LiveKit room requires an access token. Access tokens (JWT) encode the user's identity and the room permissions they've been granted. You can generate a token with our CLI:
lk token create \
--api-key devkey --api-secret secret \
--join --room my-first-room --identity user1 \
--valid-for 24h
Test with example app
Head over to our example app and enter a generated token to connect to your LiveKit server. This app is built with our React SDK.
Once connected, your video and audio are now being published to your new LiveKit instance!
Simulating a test publisher
lk room join \
--url ws://localhost:7880 \
--api-key devkey --api-secret secret \
--identity bot-user1 \
--publish-demo \
my-first-room
This command publishes a looped demo video to a room. Due to how the video clip was encoded (keyframes every 3s), there's a slight delay before the browser has sufficient data to begin rendering frames. This is an artifact of the simulation.
Deployment
Use LiveKit Cloud
LiveKit Cloud is the fastest and most reliable way to run LiveKit. Every project gets free monthly bandwidth and transcoding credits.
Sign up for LiveKit Cloud.
Self-host
Read our deployment docs for more information.
Building from source
Pre-requisites:
- Go 1.23+ is installed
- GOPATH/bin is in your PATH
Then run
git clone https://github.com/livekit/livekit
cd livekit
./bootstrap.sh
mage
Contributing
We welcome your contributions toward improving LiveKit! Please join us on Slack to discuss your ideas and/or PRs.
License
LiveKit server is licensed under Apache License v2.0.
| LiveKit Ecosystem | |
|---|---|
| LiveKit SDKs | Browser · iOS/macOS/visionOS · Android · Flutter · React Native · Rust · Node.js · Python · Unity · Unity (WebGL) |
| Server APIs | Node.js · Golang · Ruby · Java/Kotlin · Python · Rust · PHP (community) · .NET (community) |
| UI Components | React · Android Compose · SwiftUI |
| Agents Frameworks | Python · Node.js · Playground |
| Services | LiveKit server · Egress · Ingress · SIP |
| Resources | Docs · Example apps · Cloud · Self-hosting · CLI |