active-call 0.3.82

# Active Call

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`active-call` is a standalone Rust crate for building AI Voice Agents. It provides high-performance infrastructure bridging AI models with real-world telephony and web communications.

📖 **Documentation** → [English](./docs/en/README.md) | [中文](./docs/zh/README.md) | [API Reference](./docs/api.md)

## Key Capabilities

### 1. Multi-Protocol Audio Gateway

- **SIP (Telephony)**: UDP, TCP, TLS (SIPS), WebSocket. Register as extension to FreeSWITCH / Asterisk / [RustPBX](https://github.com/restsend/rustpbx), or handle direct SIP calls. PSTN via [Twilio](./docs/twilio_integration.md) and [Telnyx](./docs/telnyx_integration.md).
- **WebRTC**: Browser-to-agent SRTP. *(Requires HTTPS or 127.0.0.1)*
- **Voice over WebSocket**: Push raw PCM/encoded audio, receive real-time events.

### 2. Dual-Engine Dialogue

- **Traditional Pipeline**: VAD → ASR → LLM → TTS. Supports OpenAI, Aliyun, Azure, Tencent, Deepgram and more.
- **Realtime Streaming**: Native OpenAI/Azure Realtime API — full-duplex, ultra-low latency.
- **Audio Processing**: Built-in noise reduction (nnnoiseless), WebRTC AGC2 automatic gain control, configurable interruption strategy with filler-word filtering.

### 3. Playbook — Stateful Voice Agents

Define personas, scenes, and flows in Markdown files with rich config:

```markdown
---
asr:
  provider: "sensevoice"
tts:
  provider: "supertonic"
  speaker: "F1"
llm:
  provider: "openai"
  model: "${OPENAI_MODEL}"
  apiKey: "${OPENAI_API_KEY}"
  features: ["intent_clarification", "emotion_resonance"]
dtmf:
  "0": { action: "hangup" }
dtmfCollectors:
  order_number:
    description: "Collect order number"
    maxDigits: 6
    finishKey: "#"
    timeout: 15
interruption:
  strategy: "both"
  fillerWordFilter: true
agc: {}
denoise: true
ringbackDetection:
  enabled: true
sip:
  extractHeaders: ["X-Customer-Id"]
posthook:
  url: "https://api.example.com/webhook"
  summary: "detailed"
---

# Scene: greeting
<dtmf digit="1" action="goto" scene="tech_support" />
<dtmf digit="2" action="transfer" target="sip:billing@domain.com" />

You are a friendly AI for {{ company_name }}. Greet the caller warmly.
To look up info: <http url="https://api.example.com/user/{{ sip["X-Customer-Id"] }}" />
To collect order: <collect type="order_number" var="order_id" prompt="Please enter your 6-digit order number." />
To send metadata: <message body="order={{ order_id }}" />

# Scene: tech_support
How can I help with your system? I can transfer you: <refer to="sip:human@domain.com" />
To search knowledge base: <http url="https://kb.example.com/search" body='{"q":"{{ caller }}"}' method="POST" />
```

- `${VAR}` = environment variables (config-time). `{{var}}` = runtime variables (per-call).
- Built-in vars: `{{ session_id }}`, `{{ call_type }}`, `{{ caller }}`, `{{ callee }}`, `{{ start_time }}`
- SIP header access: `{{ sip["X-Header-Name"] }}`
- Scene-level `<collect>` triggers DTMF digit collection; results stored as `{{ var }}`.
- `<set_var key="k" value="v" />` and `<http url="..." />` extend LLM capabilities at runtime.

### 4. Offline AI (Privacy-First)

Run ASR and TTS locally — no cloud API required:

- **Offline ASR**: [SenseVoice](https://github.com/FunAudioLLM/SenseVoice) — zh, en, ja, ko, yue
- **Offline TTS**: [Supertonic](https://github.com/supertone-inc/supertonic) — en, ko, es, pt, fr

```bash
# Download models
docker run --rm -v $(pwd)/data/models:/models \
  ghcr.io/miuda-ai/active-call:latest \
  --download-models all --models-dir /models --exit-after-download

# Run with offline models
docker run -d --net host \
  -v $(pwd)/data/models:/app/models \
  -v $(pwd)/config:/app/config \
  ghcr.io/miuda-ai/active-call:latest
```

> **Mainland China**: Add `-e HF_ENDPOINT=https://hf-mirror.com` to use the HuggingFace mirror.

### 5. High-Performance Media Core

| VAD Engine      | Time (60s audio) | RTF    | Note              |
| --------------- | ---------------- | ------ | ----------------- |
| **TinySilero**  | ~60 ms           | 0.0010 | >2.5× faster ONNX |
| **ONNX Silero** | ~158 ms          | 0.0026 | Standard baseline |
| **WebRTC VAD**  | ~3 ms            | 0.00005| Legacy            |

Codec support: PCM16, G.711 (PCMU/PCMA), G.722, Opus.

### 6. Audio Processing

| Feature                | Description                                    |
|------------------------|------------------------------------------------|
| **Denoise**            | nnnoiseless-based real-time noise reduction    |
| **AGC**                | WebRTC AGC2 adaptive gain control              |
| **Ambiance**           | Background audio mixing with ducking           |
| **Interruption**       | Configurable VAD/ASR/None strategy + fade-out  |

### 7. Call Management

- **Bridge/Unbridge**: Bidirectional audio patching between two active calls (media only, no SIP signaling).
- **Pause/Resume**: Pause/resume server-side TTS or file playback.
- **Mute/Unmute**: Mute/unmute specific audio tracks.
- **Graceful Shutdown**: Waits for active calls to finish naturally before exit.

## Quick Start

```bash
# Webhook handler
./active-call --handler https://example.com/webhook

# Playbook handler
./active-call --handler config/playbook/greeting.md

# Outbound SIP call
./active-call --call sip:1001@127.0.0.1:5060 --handler greeting.md

# With external IP and codecs
./active-call --handler default.md --external-ip 1.2.3.4 --codecs pcmu,pcma,opus
```

### Docker

```bash
docker run -d --net host \
  --name active-call \
  -v $(pwd)/config.toml:/app/config.toml:ro \
  -v $(pwd)/config:/app/config \
  ghcr.io/miuda-ai/active-call:latest
```

### Playbook Handler Routing

```toml
[handler]
type = "playbook"
default = "greeting.md"

[[handler.rules]]
caller = "^\\+1\\d{10}$"
callee = "^sip:support@.*"
playbook = "support.md"

[[handler.rules]]
caller = "^\\+86\\d+"
playbook = "chinese.md"
```

## SIP Carrier Integration

### TLS + SRTP (Required by Twilio)

```toml
tls_port      = 5061
tls_cert_file = "./certs/cert.pem"
tls_key_file  = "./certs/key.pem"
enable_srtp   = true
```

- [Twilio Elastic SIP Trunking Guide](./docs/twilio_integration.md)
- [Telnyx SIP Trunking Guide](./docs/telnyx_integration.md)

## Feature Flags

| Feature                | Cargo flag                          | Description                        |
|------------------------|-------------------------------------|------------------------------------|
| **offline** (default) | `--features offline`                | SenseVoice ASR + Supertonic TTS    |
| **cross**              | `--features cross`                  | offline + AWS-LC bindgen (cross-compile) |
| **ringback-detection** | `--features ringback-detection`     | Ringback tone detection             |
| **opus**               | `--features opus`                   | Opus codec support                  |
| **not_vad**            | `--no-default-features`             | Exclude VAD (for external VAD)      |

```bash
cargo build --release
cargo build --release --features ringback-detection,opus
```

## Building from Source

```bash
# rustc may require extra stack when compiling certain crates
export RUST_MIN_STACK=16777216
cargo build --release
```

Or add to your shell profile:
```bash
echo 'export RUST_MIN_STACK=16777216' >> ~/.bashrc
```

## Environment Variables

```bash
# OpenAI / Azure
OPENAI_API_KEY=sk-...
AZURE_OPENAI_API_KEY=...
AZURE_OPENAI_ENDPOINT=https://your-resource.openai.azure.com/

# Aliyun DashScope
DASHSCOPE_API_KEY=sk-...

# Tencent Cloud
TENCENT_APPID=...
TENCENT_SECRET_ID=...
TENCENT_SECRET_KEY=...

# Deepgram
DEEPGRAM_API_KEY=...

# Offline models
OFFLINE_MODELS_DIR=/path/to/models
```

## Demo

![Playbook demo](./docs/playbook.png)

## REST API

| Method | Path                          | Description                             |
|--------|-------------------------------|-----------------------------------------|
| GET    | `/call`                       | WebSocket call handler                  |
| GET    | `/call/webrtc`                | WebRTC call handler                     |
| GET    | `/call/sip`                   | SIP call handler                        |
| GET    | `/list`                       | List all active calls                   |
| GET    | `/kill/{id}`                  | Force-terminate an active call          |
| GET    | `/events/{id}`                | SSE event stream for a call             |
| POST   | `/command/{id}`               | Send command to an active call          |
| POST   | `/precache`                   | Pre-generate TTS audio to cache         |
| GET    | `/iceservers`                 | ICE server configuration for WebRTC     |
| GET    | `/api/playbooks`              | List available playbooks                |
| GET    | `/api/playbooks/{name}`       | Get playbook content                    |
| POST   | `/api/playbooks/{name}`       | Save/update a playbook                  |
| POST   | `/api/playbook/run`           | Associate a playbook with a new session |
| GET    | `/api/records`                | List call event records                 |
| GET    | `/`                           | Serve built-in web client               |

Full command/event reference → [API Documentation](./docs/api.md)

## SDKs

- **Go**: [rustpbxgo](https://github.com/restsend/rustpbxgo) — Official Go client

## Documentation

| Language | Links |
|----------|-------|
| **English** | [Docs Hub](./docs/en/README.md) · [API Reference](./docs/api.md) · [Config Guide](./docs/en/config_guide.md) · [Playbook Tutorial](./docs/en/playbook_tutorial.md) · [Advanced Features](./docs/en/playbook_advanced_features.md) |
| **中文** | [文档中心](./docs/zh/README.md) · [API 文档](./docs/api.md) · [配置指南](./docs/zh/config_guide.md) · [Playbook 教程](./docs/zh/playbook_tutorial.md) · [高级特性](./docs/zh/playbook_advanced_features.md) |

## License

MIT — see [LICENSE](./LICENSE)