pure_dart_webrtc 1.0.4

A pure Dart implementation of WebRTC, including support for ICE, STUN, TURN, DTLS, TLS, SRTP, RTP, RTCP, and SDP.

dart_webrtc

dart_webrtc (WebrTC Implementation for The Dart language)

A pure Dart implementation of WebRTC — ICE, STUN, TURN, DTLS, TLS, SRTP, RTP, RTCP, SDP — with no native dependencies. Includes a full ion-style SFU (example/ion_style_sfu/) with sharding, clustering, simulcast, TWCC/REMB, NACK/RTX, audio observer, and Prometheus stats.

Inspired by webrtc-nuts-and-bolts

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✨ Highlights

• Pure Dart end-to-end stack — no libwebrtc / libsrtp / libnice. Easy to embed and audit.
• Ion-style SFU with isolate-based sharding, cluster coordinator, UDP relay transport, leaky-bucket pacer, BWE, jitter buffer, simulcast layer rewriter, and audio-level observer.
• 516 unit tests in the SFU package, 93–100 % line coverage across major files.
• VP8 / VP9 / Opus / PCMA / PCMU, RTX (RFC 4588), NACK, PLI, FIR, REMB, TWCC, audio level (RFC 6464), playout-delay codec.
• Built-in load-test harness and synthetic loss simulator.
• Prometheus metrics + JSON /stats endpoint.

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📦 Installation

clone the repo

Then run:

dart pub get

Requires Dart 3.x or later.

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📚 Documentation (WIP)

• API Reference
• Example usage in the /bin directory

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💡 Examples

GitHub: examples

Ion-style SFU server

dart run example/ion_style_sfu/bin/sfu_server.dart \
  --ip 0.0.0.0 \
  --ws-port 9091 \
  --rtp-base 51000 \
  --announce-ip <your-public-ip> \
  --ice-server stun:stun.l.google.com:19302

Browser demo client:

cd example/ion_style_sfu/web
python -m http.server 8000 --bind 0.0.0.0
# open http://localhost:8000/meet.html

Run the SFU test suite:

cd example/ion_style_sfu
dart test

Walkie-talkie SFU + Flutter PTT client

Push-to-talk multi-channel walkie-talkie built on top of example/ion_style_sfu/. Server adds in-memory user accounts (PBKDF2 + JWT), /auth/register, /auth/login, /channels, and a JWT-gated /ws upgrade. Flutter client (Android / iOS / macOS / Windows / Linux / Web) ships an auth screen, channel list, PTT screen with optional per-peer camera toggle (publisher renegotiation).

# server
dart run example/ion_style_sfu/bin/walkie_sfu.dart \
  --ip 0.0.0.0 --ws-port 7080 --announce-ip <public-ip>

# client
cd example/walkie_talkie_client
flutter run

See example/walkie_talkie_client/README.md.

WHIP recorder + security-camera Flutter client

Cloud / on-prem video-recording pipeline: a pure-Dart WHIP ingest server that depacketizes VP8 RTP and writes each publisher session to its own .ivf file on disk, paired with a Flutter app that captures the device camera + microphone and publishes via WHIP. Intended for unattended security-camera deployments — drop a phone or tablet running the client at every site, point it at the recorder, done.

# server (writes IVF files to ./recordings)
dart run example/whip_recorder/bin/whip_recorder.dart \
  --ip 0.0.0.0 --token <secret> --out ./recordings

# list / download recordings
curl -H "Authorization: Bearer <secret>" http://<host>:8080/recordings

# client
cd example/security_camera_client
flutter run

See example/whip_recorder/README.md and example/security_camera_client/README.md.

DTLS server

dart bin/srtp_webrtc.dart
dart bin/dart_webrtc.dart
dart lib/src/dtls/examples/server/psk_ccm8.dart
dart lib/src/dtls/examples/server/psk_ccm.dart

SRTP/DTLS server

dart bin/srtp_webrtc.dart

DTLS client

dart lib/src/dtls3/handshaker/client/dtls_client.dart

STUN Server

dart lib/src/stun3/stun_server7.dart

STUN client

dart lib/src/stun3/stun_client.dart

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STUN/DTLS/SRTP/RTCP multiplexing

This example recieves stun, dtls, rtp packets. It decrypts, encrypts and sends the packets back to the sender. copy the sdp offer from this file:

lib\src\sdp8\sdp_test.dart

Adjust the the fingerprint and ice candidate

cd WebRTC-Simple-SDP-Handshake-Demo
php -S localhost:3000

Navigate to the link in your browser=> localhost:3000 Paste the sdp in the sdp offer box

Run this command

dart bin\srtp_webrtc.dart

In your browser, click create answer

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🎯 Roadmap

✅ Shipped

Signaling & NAT traversal

• ✅ STUN (client + server)
• ✅ SIP
• ❌ TURN (UDP)

ICE

• ✅ Vanilla ICE
• ✅ Trickle ICE
• ✅ ICE-Lite (client + server)
• ❌ ICE Restart

Security

• ✅ DTLS 1.2 + DTLS-SRTP
  • ✅ Curve25519, P-256
  • ✅ PSK (CCM, CCM-8)
• ❌ TLS 1.2

RTP / RTCP

• ✅ RFC 3550 RTP base + header extensions (audio level, playout delay, abs-send-time, TWCC)
• ✅ Payload formats: VP8, VP9, Opus, PCMA, PCMU
• ✅ RTX (RFC 4588), RED scaffolding
• ✅ RTCP: SR/RR, NACK, PLI, FIR, REMB, TWCC
• ❌ H264, AV1, SVC

SDP / PeerConnection

• ✅ SDP parsing + generation, m-line reuse
• ✅ PeerConnection API
• ✅ Simulcast (RID + SIM SSRC group, recv + forward)
• ✅ Bandwidth estimation (sender-side TWCC + REMB)

SFU (example/ion_style_sfu/)

• ✅ Session / Peer / Publisher / Subscriber / Router / Receiver / DownTrack
• ✅ Isolate-based session sharding (SessionShard, ShardedSfu)
• ✅ Cluster coordinator + UDP relay transport (cascade between SFUs)
• ✅ Audio observer (RFC 6464) + audio-level forwarding policy
• ✅ Leaky-bucket pacer, byte budget, NACK buffer, RTCP rewrite
• ✅ Synthetic loss simulator + load-test harness
• ✅ Prometheus stats + JSON snapshot, /streams aggregator (Phase B11)
• ✅ WebSocket signalling server (runIonStyleSfuServer)
• ✅ Multi-room cluster snapshot rehydration

Compatibility

• ✅ Chrome / Edge / Firefox
• ✅ webrtc-rs interop
• ❌ Pion / aiortc / sipsorcery interop suite

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🔜 Roadmap

• ❌ VP9 SVC layer selector
• ❌ H264 forwarding
• ❌ Insertable streams / SFrame (E2EE)
• ✅ Recording (VP8 → IVF, via example/whip_recorder/)
• ❌ Recording (Opus, VP9 → IVF, MP4 remux)
• ❌ Published throughput benchmarks + Helm chart
• ❌ DataChannel (SCTP)
• ❌ TURN (UDP + TCP)
• ❌ getStats() browser-compatible API
• ❌ ICE Restart

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🔗 References

• aiortc (Python)
• pion/webrtc (Go)
• sipsorcery (C#)
• webrtc-rs (Rust)