npm package: @spatialwalk/avatarkit
Description: AvatarKit SDK - 3D Gaussian Splatting Avatar Rendering SDK
Author: AvatarKit Team
Latest version: 1.0.0-beta.98

# AvatarKit SDK

Real-time virtual avatar rendering SDK for Web, supporting audio-driven animation and high-quality 3D rendering.

## 🚀 Features

- **High-Quality 3D Rendering** - GPU-accelerated avatar rendering with automatic backend selection
- **Audio-Driven Real-Time Animation** - Send audio data, SDK handles animation and rendering
- **Multi-Avatar Support** - Support multiple avatar instances simultaneously, each with independent state and rendering
- **TypeScript Support** - Complete type definitions and IntelliSense
- **Modular Architecture** - Clear component separation, easy to integrate and extend

## 📦 Installation

```bash
npm install @spatialwalk/avatarkit
```

## 🚧 Release Gate (Hard Rule)

Release must pass gates before publish. Do not publish by manual ad-hoc commands.

Required gate checks:

```bash
pnpm typecheck
pnpm test
pnpm build
./tools/check_perf_baseline_release_gate.sh
```

If iteration includes bugfixes, `docs/bugfix-history.md` must have completed rows (test mapping + red/green evidence).

Hotfix bypass is allowed only for emergency and must be recorded:

```bash
HOTFIX_BYPASS=1 ./tools/check_perf_baseline_release_gate.sh
```

## 🧪 Benchmark Demo (Web SDK)

Use the dedicated benchmark demo (independent from `vanilla/`) for perf/render baseline runs:

```bash
pnpm demo:benchmark
```

## 🚀 Demo Repository

<div align="center">

### 📌 **Quick Start: Check Out Our Demo Repository**

We provide complete example code and best practices to help you quickly integrate the SDK.

**The demo repository includes:**
- ✅ Complete integration examples
- ✅ Usage examples for both SDK mode and Host mode  
- ✅ Audio processing examples (PCM16, WAV, MP3, etc.)
- ✅ Vite configuration examples
- ✅ Next.js configuration examples
- ✅ Best practices for common scenarios

**[👉 View Demo Repository](https://github.com/spatialwalk/avatarkit-demo)** | *If not yet created, please contact the team*

</div>

---

## 🔧 Vite Configuration (Recommended)

If you are using Vite as your build tool, we strongly recommend using our Vite plugin to automatically handle WASM file configuration. The plugin automatically handles all necessary configurations, so you don't need to set them up manually.

### Using the Plugin

Add the plugin to `vite.config.ts`:

```typescript
import { defineConfig } from 'vite'
import { avatarkitVitePlugin } from '@spatialwalk/avatarkit/vite'

export default defineConfig({
  plugins: [
    avatarkitVitePlugin(), // Just add this line
  ],
})
```

### Plugin Features

The plugin automatically handles:

- ✅ **Development Server**: Automatically sets the correct MIME type (`application/wasm`) for WASM files
- ✅ **Build Time**: Automatically copies WASM files to `dist/assets/` directory
- ✅ **Cloudflare Pages**: Automatically generates `_headers` file to ensure WASM files use the correct MIME type
- ✅ **Vite Configuration**: Automatically configures `optimizeDeps`, `assetsInclude`, `assetsInlineLimit`, and other options

### Manual Configuration (Without Plugin)

If you don't use the Vite plugin, you need to manually configure the following:

```typescript
// vite.config.ts
export default defineConfig({
  optimizeDeps: {
    exclude: ['@spatialwalk/avatarkit'],
  },
  assetsInclude: ['**/*.wasm'],
  build: {
    assetsInlineLimit: 0,
    rollupOptions: {
      output: {
        assetFileNames: (assetInfo) => {
          if (assetInfo.name?.endsWith('.wasm')) {
            return 'assets/[name][extname]'
          }
          return 'assets/[name]-[hash][extname]'
        },
      },
    },
  },
  // Development server needs to manually configure middleware to set WASM MIME type
  configureServer(server) {
    server.middlewares.use((req, res, next) => {
      if (req.url?.endsWith('.wasm')) {
        res.setHeader('Content-Type', 'application/wasm')
      }
      next()
    })
  },
})
```

## 🔧 Next.js Configuration

For Next.js projects, use the `withAvatarkit` wrapper to automatically handle WASM file configuration with webpack.

### Using the Plugin

Wrap your Next.js config in `next.config.mjs`:

```javascript
import { withAvatarkit } from '@spatialwalk/avatarkit/next'

export default withAvatarkit({
  // ...your existing Next.js config
})
```

### Plugin Features

The plugin automatically handles:

- ✅ **Path Fix**: Patches asset path resolution so WASM files are correctly loaded at `/_next/static/chunks/`
- ✅ **WASM Copying**: Copies `.wasm` files into `static/chunks/` via a custom webpack plugin (client build only)
- ✅ **Content-Type Headers**: Adds `application/wasm` response header for `/_next/static/chunks/*.wasm`
- ✅ **Config Chaining**: Preserves your existing `webpack` and `headers` configurations

## 🔐 Authentication

All environments require an **App ID** and **Session Token** for authentication.

### App ID

The App ID is used to identify your application. You can obtain your App ID by:

1. **For Testing**: Use the default test App ID provided in demo repositories (paired with test Session Token, only works with publicly available test avatars like Rohan, Dr.Kellan, Priya, Josh, etc.)
2. **For Production**: Visit the [Developer Platform](https://dash.spatialreal.ai) to create your own App and avatars. You will receive your own App ID after creating an App.

### Session Token

The Session Token is required for authentication and must be obtained from your SDK provider.

**⚠️ Important Notes:**
- The Session Token must be valid and not expired
- In production applications, you **must** manually inject a valid Session Token obtained from your SDK provider
- The default Session Token provided in demo repositories is **only for demonstration purposes** and can only be used with test avatars
- If you want to create your own avatars and test them, please visit the [Developer Platform](https://dash.spatialreal.ai) to create your own App and generate Session Tokens

**How to Set Session Token:**

```typescript
// Initialize SDK with App ID
await AvatarSDK.initialize('your-app-id', configuration)

// Set Session Token (can be called before or after initialization)
// If called before initialization, the token will be automatically set when you initialize the SDK
AvatarSDK.setSessionToken('your-session-token')

// Get current Session Token
const sessionToken = AvatarSDK.sessionToken
```

**Token Management:**
- The Session Token can be set at any time using `AvatarSDK.setSessionToken(token)`
- If you set the token before initializing the SDK, it will be automatically applied during initialization
- If you set the token after initialization, it will be applied immediately
- Handle token refresh logic in your application as needed (e.g., when token expires)

**For Production Integration:**
- Obtain a valid Session Token from your SDK provider
- Store the token securely (never expose it in client-side code if possible)
- Implement token refresh logic to handle token expiration
- Use `AvatarSDK.setSessionToken(token)` to inject the token programmatically

## 🎯 Quick Start

### ⚠️ Important: Audio Context Initialization

**Before using any audio-related features, you MUST initialize the audio context in a user gesture context** (e.g., `click`, `touchstart` event handlers). This is required by browser security policies. Calling `initializeAudioContext()` outside a user gesture will fail.

### Basic Usage

```typescript
import { 
  AvatarSDK, 
  AvatarManager, 
  AvatarView,
  Configuration,
  Environment,
  DrivingServiceMode,
  LogLevel
} from '@spatialwalk/avatarkit'

// 1. Initialize SDK

const configuration: Configuration = {
  environment: Environment.cn,
  drivingServiceMode: DrivingServiceMode.sdk, // Optional, 'sdk' is default
  // - DrivingServiceMode.sdk: SDK mode - SDK handles network communication
  // - DrivingServiceMode.host: Host mode - Host app provides audio and animation data
  logLevel: LogLevel.off, // Optional, 'off' is default
  // - LogLevel.off: Disable all logs
  // - LogLevel.error: Only error logs
  // - LogLevel.warning: Warning and error logs
  // - LogLevel.all: All logs (info, warning, error)
  audioFormat: { // Default is { channelCount: 1, sampleRate: 16000 }
    channelCount: 1, // Fixed to 1 (mono)
    sampleRate: 16000 // Supported: 8000, 16000, 22050, 24000, 32000, 44100, 48000 Hz
    // ⚠️ Must match your actual audio sample rate. Mismatched sample rate will cause playback issues.
  }
  // characterApiBaseUrl: 'https://custom-api.example.com' // Optional, internal debug config, can be ignored
}

await AvatarSDK.initialize('your-app-id', configuration)

// Set Session Token (required for authentication)
// You must obtain a valid Session Token from your SDK provider
// See Authentication section above for more details
AvatarSDK.setSessionToken('your-session-token')

// 2. Load avatar
const avatarManager = AvatarManager.shared
const avatar = await avatarManager.load('character-id', (progress) => {
  console.log(`Loading progress: ${progress.progress}%`)
})

// 3. Create view (automatically creates Canvas and AvatarController)
// The playback mode is determined by drivingServiceMode in AvatarSDK configuration
// - DrivingServiceMode.sdk: SDK mode - SDK handles network communication
// - DrivingServiceMode.host: Host mode - Host app provides audio and animation data
const container = document.getElementById('avatar-container')
const avatarView = new AvatarView(avatar, container)

// 4. ⚠️ CRITICAL: Initialize audio context (MUST be called in user gesture context)
// This method MUST be called within a user gesture event handler (click, touchstart, etc.)
// to satisfy browser security policies. Calling it outside a user gesture will fail.
button.addEventListener('click', async () => {
  // Initialize audio context - MUST be in user gesture context
  await avatarView.controller.initializeAudioContext()
  
  // 5. Start real-time communication (SDK mode only)
  // Note: start() initiates the WebSocket connection asynchronously.
  // Wait for onConnectionState === 'connected' before calling send().
  await avatarView.controller.start()

  // 6. Wait for connection to be ready
  await new Promise<void>((resolve) => {
    avatarView.controller.onConnectionState = (state) => {
      if (state === ConnectionState.connected) resolve()
    }
  })

  // 7. Send audio data (SDK mode, must be mono PCM16 format matching configured sample rate)
  // audioData: ArrayBuffer or Uint8Array containing PCM16 (S16LE) audio samples
  // ⚠️ Byte length MUST be even (2 bytes per sample). Odd-length data will cause server-side
  //    validation error and WebSocket disconnect.
  // - PCM files: Can be directly read as ArrayBuffer
  // - WAV files: Extract PCM data from WAV format (may require resampling)
  // - MP3 files: Decode first (e.g., using AudioContext.decodeAudioData()), then convert to PCM16
  const audioData = new ArrayBuffer(1024) // Placeholder: Replace with actual PCM16 audio data
  avatarView.controller.send(audioData, false) // Send audio data
  avatarView.controller.send(audioData, true) // end=true marks the end of current conversation round
})
```

### Host Mode Example

```typescript

// 1-3. Same as SDK mode (initialize SDK, load avatar)

// 3. Create view with Host mode
const container = document.getElementById('avatar-container')
const avatarView = new AvatarView(avatar, container)

// 4. ⚠️ CRITICAL: Initialize audio context (MUST be called in user gesture context)
// This method MUST be called within a user gesture event handler (click, touchstart, etc.)
// to satisfy browser security policies. Calling it outside a user gesture will fail.
button.addEventListener('click', async () => {
  // Initialize audio context - MUST be in user gesture context
  await avatarView.controller.initializeAudioContext()
  
  // 5. Host Mode Workflow:
  // Send audio data first to get conversationId, then use it to send animation data
  const conversationId = avatarView.controller.yieldAudioData(audioData, false)
  avatarView.controller.yieldFramesData(animationDataArray, conversationId) // animationDataArray: (Uint8Array | ArrayBuffer)[]
```

### Complete Examples

This SDK supports two usage modes:
- SDK mode: Real-time audio input with automatic animation data reception
- Host mode: Custom data sources with manual audio/animation data management

## 🏗️ Architecture Overview

### Core Components

- **AvatarSDK** - SDK initialization and management
- **AvatarManager** - Avatar resource loading and management
- **AvatarView** - 3D rendering view
- **AvatarController** - Audio/animation playback controller

### Playback Modes

The SDK supports two playback modes, configured in `AvatarSDK.initialize()`:

#### 1. SDK Mode (Default)
- Configured via `drivingServiceMode: DrivingServiceMode.sdk` in `AvatarSDK.initialize()`
- SDK handles network communication automatically
- Send audio data via `AvatarController.send()`
- SDK receives animation data from backend and synchronizes playback
- Best for: Real-time audio input scenarios

#### 2. Host Mode
- Configured via `drivingServiceMode: DrivingServiceMode.host` in `AvatarSDK.initialize()`
- Host application manages its own network/data fetching
- Host application provides both audio and animation data
- SDK only handles synchronized playback
- Best for: Custom data sources, pre-recorded content, or custom network implementations

**Note:** The playback mode is determined by `drivingServiceMode` in `AvatarSDK.initialize()` configuration.

### Fallback Mechanism

The SDK includes a fallback mechanism to ensure audio playback continues even when animation data is unavailable:

- **SDK Mode Connection Failure**: If connection fails to establish within 15 seconds, the SDK automatically enters fallback mode. Audio data can still be sent and will play normally, even though no animation data will be received. This ensures audio playback is not interrupted.
- **SDK Mode Server Error**: If the server returns an error after connection is established, the SDK automatically enters audio-only mode for that session.
- **Host Mode**: If empty animation data is provided (empty array or undefined), the SDK automatically enters audio-only mode.
- Once in audio-only mode, any subsequent animation data for that session will be ignored, and only audio will continue playing.
- The fallback mode is interruptible, just like normal playback mode.
- Connection state callbacks (`onConnectionState`) will notify you when connection fails or times out.

### Data Flow

#### SDK Mode Flow

```
Audio input (PCM16 mono)
    ↓
AvatarController.send()
    ↓
Backend processing → Animation data
    ↓
SDK synchronizes audio + animation playback
    ↓
GPU rendering → Canvas
```

#### Host Mode Flow

```
External data source (audio + animation)
    ↓
AvatarController.yieldAudioData(audioChunk)       → returns conversationId
AvatarController.yieldFramesData(dataArray, conversationId)
    ↓
SDK synchronizes audio + animation playback
    ↓
GPU rendering → Canvas
```

### Audio Format Requirements

**⚠️ Important:** The SDK requires audio data to be in **mono PCM16** format:

- **Sample Rate**: Configurable via `audioFormat.sampleRate` in SDK initialization (default: 16000 Hz)
  - Supported sample rates: 8000, 16000, 22050, 24000, 32000, 44100, 48000 Hz
  - The configured sample rate will be used for both audio recording and playback
- **Channels**: Mono (single channel) - Fixed to 1 channel
- **Format**: PCM16 (16-bit signed integer, little-endian)
- **Byte Order**: Little-endian

**Audio Data Format:**
- Each sample is 2 bytes (16-bit signed integer, little-endian)
- Audio data should be provided as `ArrayBuffer` or `Uint8Array`
- For example, with 16kHz sample rate: 1 second of audio = 16000 samples × 2 bytes = 32000 bytes
- For 48kHz sample rate: 1 second of audio = 48000 samples × 2 bytes = 96000 bytes

**Audio Data Source:**
The `audioData` parameter represents raw PCM16 audio samples in the configured sample rate and mono format. Common audio sources include:
- **PCM files**: Raw PCM16 files can be directly read as `ArrayBuffer` or `Uint8Array` and sent to the SDK (ensure sample rate matches configuration)
- **WAV files**: WAV files contain PCM16 audio data in their data chunk. After extracting the PCM data from the WAV file format, it can be sent to the SDK (may require resampling if sample rate differs)
- **MP3 files**: MP3 files need to be decoded first (e.g., using `AudioContext.decodeAudioData()` or a decoder library), then converted from the decoded format to PCM16 before sending to the SDK
- **Microphone input**: Real-time microphone audio needs to be captured and converted to PCM16 format at the configured sample rate before sending
- **Other audio sources**: Any audio source must be converted to mono PCM16 format at the configured sample rate before sending

**Example: Processing WAV and MP3 Files:**
```typescript
// WAV file processing
async function processWAVFile(wavFile: File): Promise<ArrayBuffer> {
  const arrayBuffer = await wavFile.arrayBuffer()
  const view = new DataView(arrayBuffer)
  
  // WAV format: Skip header (usually 44 bytes for standard WAV)
  // Check RIFF header
  if (view.getUint32(0, true) !== 0x46464952) { // "RIFF"
    throw new Error('Invalid WAV file')
  }
  
  // Find "data" chunk (offset may vary)
  let dataOffset = 44 // Standard WAV header size
  // For non-standard WAV files, you may need to search for "data" chunk
  // This is a simplified example - production code should parse chunks properly
  
  const pcmData = arrayBuffer.slice(dataOffset)
  return pcmData
}

// MP3 file processing
async function processMP3File(mp3File: File, targetSampleRate: number): Promise<ArrayBuffer> {
  const arrayBuffer = await mp3File.arrayBuffer()
  const audioContext = new AudioContext({ sampleRate: targetSampleRate })
  
  // Decode MP3 to AudioBuffer
  const audioBuffer = await audioContext.decodeAudioData(arrayBuffer.slice(0))
  
  // Convert AudioBuffer to PCM16 ArrayBuffer
  const length = audioBuffer.length
  const channels = audioBuffer.numberOfChannels
  const pcm16Buffer = new ArrayBuffer(length * 2)
  const pcm16View = new DataView(pcm16Buffer)
  
  // Mix down to mono if stereo
  const sourceData = channels === 1 
    ? audioBuffer.getChannelData(0)
    : new Float32Array(length)
  
  if (channels > 1) {
    const leftChannel = audioBuffer.getChannelData(0)
    const rightChannel = audioBuffer.getChannelData(1)
    for (let i = 0; i < length; i++) {
      sourceData[i] = (leftChannel[i] + rightChannel[i]) / 2 // Mix to mono
    }
  }
  
  // Convert float32 (-1.0 to 1.0) to int16 (-32768 to 32767)
  for (let i = 0; i < length; i++) {
    const sample = Math.max(-1, Math.min(1, sourceData[i])) // Clamp
    const int16Sample = sample < 0 ? sample * 0x8000 : sample * 0x7FFF
    pcm16View.setInt16(i * 2, int16Sample, true) // little-endian
  }
  
  audioContext.close()
  return pcm16Buffer
}

// Usage example:
// const wavPcmData = await processWAVFile(wavFile)
// avatarView.controller.send(wavPcmData, false)
//
// const mp3PcmData = await processMP3File(mp3File, 16000) // 16kHz
// avatarView.controller.send(mp3PcmData, false)
```

**Resampling:**
- If your audio source is at a different sample rate, you must resample it to match the configured sample rate before sending to the SDK
- For high-quality resampling, we recommend using Web Audio API's `OfflineAudioContext` with anti-aliasing filtering
- See example projects for resampling implementation

**Configuration Example:**
```typescript
const configuration: Configuration = {
  environment: Environment.cn,
  audioFormat: {
    channelCount: 1, // Fixed to 1 (mono)
    sampleRate: 48000 // Choose from: 8000, 16000, 22050, 24000, 32000, 44100, 48000
  }
}
```

## 📚 API Reference

### AvatarSDK

The core management class of the SDK, responsible for initialization and global configuration.

```typescript
// Initialize SDK
await AvatarSDK.initialize(appId: string, configuration: Configuration)

// Check initialization status
const isInitialized = AvatarSDK.isInitialized

// Get initialized app ID
const appId = AvatarSDK.appId

// Get configuration
const config = AvatarSDK.configuration

// Set Session Token (required for authentication)
// You must obtain a valid Session Token from your SDK provider
// See Authentication section for more details
AvatarSDK.setSessionToken('your-session-token')

// Set userId (optional, for telemetry)
AvatarSDK.setUserId('user-id')

// Get sessionToken
const sessionToken = AvatarSDK.sessionToken

// Get userId
const userId = AvatarSDK.userId

// Get SDK version
const version = AvatarSDK.version

// Cleanup resources (must be called when no longer in use)
AvatarSDK.cleanup()
```

### AvatarManager

Avatar resource manager, responsible for downloading, caching, and loading avatar data. Use the singleton instance via `AvatarManager.shared`.

```typescript
// Get singleton instance
const manager = AvatarManager.shared

// Load avatar
const avatar = await manager.load(
  id: string, 
  onProgress?: (progress: LoadProgressInfo) => void
)

// Clear cache
manager.clearAll()
```

### AvatarView

3D rendering view, responsible for 3D rendering only. Internally automatically creates and manages `AvatarController`.

```typescript
constructor(avatar: Avatar, container: HTMLElement)
```

**Parameters:**
- `avatar`: Avatar instance
- `container`: Canvas container element (required)
  - Canvas automatically uses the full size of the container (width and height)
  - Canvas aspect ratio adapts to container size - set container size to control aspect ratio
  - Canvas will be automatically added to the container
  - SDK automatically handles resize events via ResizeObserver

**Playback Mode:**
- The playback mode is determined by `drivingServiceMode` in `AvatarSDK.initialize()` configuration
- The playback mode is fixed when creating `AvatarView` and persists throughout its lifecycle
- Cannot be changed after creation

```typescript
// Create view (Canvas is automatically added to container)
const container = document.getElementById('avatar-container')
const avatarView = new AvatarView(avatar, container)

// Wait for first frame to render
avatarView.onFirstRendering = () => {
  // First frame rendered
}

// Get or set avatar transform (position and scale)
// Get current transform
const currentTransform = avatarView.avatarTransform // { x: number, y: number, scale: number }

// Set transform
avatarView.avatarTransform = { x, y, scale }
// - x: Horizontal offset in normalized coordinates (-1 to 1, where -1 = left edge, 0 = center, 1 = right edge)
// - y: Vertical offset in normalized coordinates (-1 to 1, where -1 = bottom edge, 0 = center, 1 = top edge)
// - scale: Scale factor (1.0 = original size, 2.0 = double size, 0.5 = half size)

// Cleanup resources (must be called before switching avatars)
avatarView.dispose()
```

**Switching Avatars:**

To switch avatars, dispose the old view and create a new one. Do NOT attempt to reuse or reset an existing AvatarView.
- `AvatarSDK.initialize()` and session token do not need to be called again.
- The old AvatarView's internal state is fully cleaned up by `dispose()`.

```typescript
// 1. Dispose old avatar
if (currentAvatarView) {
  currentAvatarView.dispose()
}

// 2. Load new avatar (SDK is already initialized, token is still valid)
const newAvatar = await AvatarManager.shared.load('new-character-id')

// 3. Create new AvatarView
currentAvatarView = new AvatarView(newAvatar, container)

// 4. Start connection if SDK mode
await currentAvatarView.controller.start()
```

### AvatarController

Audio/animation playback controller, manages synchronized playback of audio and animation. Automatically handles network communication in SDK mode.

**Two Usage Patterns:**

#### SDK Mode Methods

```typescript
// ⚠️ CRITICAL: Initialize audio context first (MUST be called in user gesture context)
// This method MUST be called within a user gesture event handler (click, touchstart, etc.)
// to satisfy browser security policies. Calling it outside a user gesture will fail.
// All audio operations (start, send, etc.) require prior initialization.
button.addEventListener('click', async () => {
  // Initialize audio context - MUST be in user gesture context
  await avatarView.controller.initializeAudioContext()
  
  // Start service
  await avatarView.controller.start()

  // Send audio data (must be mono PCM16 format matching configured sample rate)
  const conversationId = avatarView.controller.send(audioData: ArrayBuffer, end: boolean)
  // Returns: conversationId - Conversation ID for this conversation session
  // end: false (default) - Continue sending audio data for current conversation
  // end: true - Mark the end of audio input for current conversation round. The avatar will continue playing remaining animation until finished, then automatically return to idle (notified via onConversationState). After end=true, sending new audio data will interrupt any ongoing playback from the previous conversation round
})

// Close service
avatarView.controller.close()
```

#### Host Mode Methods

```typescript
// ⚠️ CRITICAL: Initialize audio context first (MUST be called in user gesture context)
// This method MUST be called within a user gesture event handler (click, touchstart, etc.)
// to satisfy browser security policies. Calling it outside a user gesture will fail.
// All audio operations (yieldAudioData, yieldFramesData, etc.) require prior initialization.
button.addEventListener('click', async () => {
  // Initialize audio context - MUST be in user gesture context
  await avatarView.controller.initializeAudioContext()
  
  // Stream audio chunks (must be mono PCM16 format matching configured sample rate)
  const conversationId = avatarView.controller.yieldAudioData(
    data: Uint8Array,               // Audio chunk data (PCM16 format)
    isLast: boolean = false         // Whether this is the last chunk
  )
  // Returns: conversationId - Conversation ID for this audio session

  // Stream animation keyframes (requires conversationId from audio data)
  avatarView.controller.yieldFramesData(
    keyframesDataArray: (Uint8Array | ArrayBuffer)[],  // Animation keyframes binary data array
    conversationId: string                              // Conversation ID (required)
  )
})
```

**⚠️ Important: Conversation ID (conversationId) Management**

**SDK Mode:**
- `send()` returns a conversationId to distinguish each conversation round
- `end=true` marks the end of a conversation round

**Host Mode:**
- `yieldAudioData()` returns a conversationId (automatically generates if starting new session)
   - `yieldFramesData()` requires a valid conversationId parameter
   - Animation data with mismatched conversationId will be **discarded**
   - Use `getCurrentConversationId()` to retrieve the current active conversationId

#### Common Methods (Both Modes)

```typescript

// Pause playback (from playing state)
avatarView.controller.pause()

// Resume playback (from paused state)
await avatarView.controller.resume()

// Interrupt current playback (stops and clears data)
avatarView.controller.interrupt()

// Clear all data and resources
avatarView.controller.clear()

// Get current conversation ID (for Host mode)
const conversationId = avatarView.controller.getCurrentConversationId()
// Returns: Current conversationId for the active audio session, or null if no active session

// Volume control (affects only avatar audio player, not system volume)
avatarView.controller.volume = 0.5  // Set volume to 50% (0.0 to 1.0)
const currentVolume = avatarView.controller.volume  // Get current volume (0.0 to 1.0)

// Set event callbacks
avatarView.controller.onConnectionState = (state: ConnectionState) => {} // SDK mode only
avatarView.controller.onConversationState = (state: ConversationState) => {}
avatarView.controller.onError = (error: AvatarError) => {} // Includes error.code for specific error type
```

#### Avatar Transform Methods

```typescript
// Get or set avatar transform (position and scale in canvas)
// Get current transform
const currentTransform = avatarView.avatarTransform // { x: number, y: number, scale: number }

// Set transform
avatarView.avatarTransform = { x, y, scale }
// - x: Horizontal offset in normalized coordinates (-1 to 1, where -1 = left edge, 0 = center, 1 = right edge)
// - y: Vertical offset in normalized coordinates (-1 to 1, where -1 = bottom edge, 0 = center, 1 = top edge)
// - scale: Scale factor (1.0 = original size, 2.0 = double size, 0.5 = half size)
// Example:
avatarView.avatarTransform = { x: 0, y: 0, scale: 1.0 }  // Center, original size
avatarView.avatarTransform = { x: 0.5, y: 0, scale: 2.0 } // Right half, double size
```

**Important Notes:**
- `start()` and `close()` are only available in SDK mode
- `yieldAudioData()` and `yieldFramesData()` are only available in Host mode
- `pause()`, `resume()`, `interrupt()`, `clear()`, `getCurrentConversationId()`, and `volume` property are available in both modes
- The playback mode is determined when creating `AvatarView` and cannot be changed

## 🔧 Configuration

### Configuration

```typescript
interface Configuration {
  environment: Environment
  drivingServiceMode?: DrivingServiceMode  // Optional, default is 'sdk' (SDK mode)
  logLevel?: LogLevel  // Optional, default is 'off' (no logs)
  audioFormat?: AudioFormat  // Optional, default is { channelCount: 1, sampleRate: 16000 }
  characterApiBaseUrl?: string  // Optional, internal debug config, can be ignored
}

interface AudioFormat {
  readonly channelCount: 1  // Fixed to 1 (mono)
  readonly sampleRate: number  // Supported: 8000, 16000, 22050, 24000, 32000, 44100, 48000 Hz, default: 16000
}
```

### LogLevel

Control the verbosity of SDK logs:

```typescript
enum LogLevel {
  off = 'off',        // Disable all logs
  error = 'error',    // Only error logs
  warning = 'warning', // Warning and error logs
  all = 'all'         // All logs (info, warning, error) - default
}
```

**Note:** `LogLevel.off` completely disables all logging, including error logs. Use with caution in production environments.

**Description:**
- `environment`: Specifies the environment (cn/intl), SDK will automatically use the corresponding server addresses based on the environment
- `drivingServiceMode`: Specifies the driving service mode
  - `DrivingServiceMode.sdk` (default): SDK mode - SDK handles network communication automatically
  - `DrivingServiceMode.host`: Host mode - Host application provides audio and animation data
- `logLevel`: Controls the verbosity of SDK logs
  - `LogLevel.off` (default): Disable all logs
  - `LogLevel.error`: Only error logs
  - `LogLevel.warning`: Warning and error logs
  - `LogLevel.all`: All logs (info, warning, error)
- `audioFormat`: Configures audio sample rate and channel count
  - `channelCount`: Fixed to 1 (mono channel)
  - `sampleRate`: Audio sample rate in Hz (default: 16000)
    - Supported values: 8000, 16000, 22050, 24000, 32000, 44100, 48000
    - The configured sample rate will be used for both audio recording and playback
- `characterApiBaseUrl`: Internal debug config, can be ignored
- `sessionToken`: **Required for authentication**. Set separately via `AvatarSDK.setSessionToken()`, not in Configuration. See [Authentication](#-authentication) section for details

```typescript
enum Environment {
  cn = 'cn',    // China region
  intl = 'intl',    // International region
}
```

### CameraConfig

```typescript
interface CameraConfig {
  position: [number, number, number]  // Camera position
  target: [number, number, number]    // Camera target
  fov: number                         // Field of view angle
  near: number                        // Near clipping plane
  far: number                         // Far clipping plane
  up?: [number, number, number]       // Up direction
  aspect?: number                     // Aspect ratio
}
```

## 📊 State Management

### ConnectionState

```typescript
enum ConnectionState {
  disconnected = 'disconnected',
  connecting = 'connecting',
  connected = 'connected',
  failed = 'failed'
}
```

### ConversationState

```typescript
enum ConversationState {
  idle = 'idle',      // Idle state (breathing animation)
  playing = 'playing', // Playing state (active conversation)
  pausing = 'pausing' // Pausing state (paused during playback)
}
```

**State Description:**
- `idle`: Avatar is in idle state (breathing animation), waiting for conversation to start
- `playing`: Avatar is playing conversation content (including during transition animations)
- `pausing`: Avatar playback is paused (e.g., when `end=false` and waiting for more audio data)

**Note:** During transition animations, the target state is notified immediately:
- When transitioning from `idle` to `playing`, the `playing` state is notified immediately
- When transitioning from `playing` to `idle`, the `idle` state is notified immediately

## 🎨 Rendering System

The SDK automatically selects the best rendering backend for your browser, no manual configuration needed.

## 🚨 Error Handling

### AvatarError

The SDK uses custom error types, providing more detailed error information:

```typescript
import { AvatarError } from '@spatialwalk/avatarkit'

try {
  await avatarView.controller.start()
} catch (error) {
  if (error instanceof AvatarError) {
    console.error('SDK Error:', error.message, error.code)
  } else {
    console.error('Unknown error:', error)
  }
}
```

### Error Callbacks

```typescript
import { AvatarError } from '@spatialwalk/avatarkit'

avatarView.controller.onError = (error: AvatarError) => {
  console.error('Error:', error.code, error.message)
}
```

`error.code` values (from `ErrorCode` enum):

| Code | Description | Trigger |
|------|-------------|---------|
| **Authentication & Authorization** | | |
| `appIDUnrecognized` | App ID not recognized | Reserved |
| `sessionTokenInvalid` | Token invalid or appId mismatch | WebSocket close code 4010 |
| `sessionTokenExpired` | Token expired | WebSocket close code 4010 |
| `insufficientBalance` | Insufficient balance | WebSocket close code 4001 |
| `concurrentLimitExceeded` | Concurrent connection limit exceeded | WebSocket close code 4003 |
| **Resource Loading** | | |
| `avatarIDUnrecognized` | Avatar ID not found | Server error |
| `failedToFetchAvatarMetadata` | Metadata fetch failed | Network/server error |
| `failedToDownloadAvatarAssets` | Asset download failed | Network/server error |
| **Connection** | | |
| `websocketError` | WebSocket handshake or network error | Connection failure |
| `websocketClosedAbnormally` | Connection closed abnormally | Close code 1006 |
| `websocketClosedUnexpected` | Unexpected close code | Unknown close code |
| `sessionTimeout` | Session timeout | WebSocket close code 4002 |
| `connectionInProgress` | Connection already in progress | Duplicate `start()` call |
| **Playback** | | |
| `networkLayerNotAvailable` | Network layer not available | `send()` in host mode |
| `playbackStartFailed` | Failed to start playback | Internal error |
| `playbackInitFailed` | Playback initialization failed | Internal error |
| `audioOnlyInitFailed` | Audio-only playback init failed | Fallback mode error |
| `noAudio` | No audio data to play | Empty audio input |
| `audioContextNotInitialized` | Audio context not initialized | `send()` before `initializeAudioContext()` |
| `animationPlayerNotInitialized` | Animation player not initialized | Internal error |
| **Server** | | |
| `serverError` | Server-side error | Server MESSAGE_SERVER_ERROR |

## 🔄 Resource Management

### Lifecycle Management

#### SDK Mode Lifecycle

```typescript
// Initialize
const container = document.getElementById('avatar-container')
const avatarView = new AvatarView(avatar, container)
await avatarView.controller.start()

// Use
avatarView.controller.send(audioData, false)

// Cleanup - dispose() automatically cleans up all resources including connections
avatarView.dispose()
```

#### Host Mode Lifecycle

```typescript
// Initialize
const container = document.getElementById('avatar-container')
const avatarView = new AvatarView(avatar, container)

// Use
const conversationId = avatarView.controller.yieldAudioData(audioChunk, false)
avatarView.controller.yieldFramesData(keyframesDataArray, conversationId)

// Cleanup - dispose() automatically cleans up all resources including playback data
avatarView.dispose()
```

**⚠️ Important Notes:**
- `dispose()` automatically cleans up all resources, including:
  - Network connections (SDK mode)
  - Playback data and animation resources (both modes)
  - Render system and canvas elements
  - All event listeners and callbacks
- Not properly calling `dispose()` may cause resource leaks and rendering errors
- If you need to manually close connections or clear playback data before disposing, you can call `avatarView.controller.close()` (SDK mode) or `avatarView.controller.clear()` (both modes) first, but it's not required as `dispose()` handles this automatically

### Memory Optimization

- SDK automatically manages memory allocation
- Supports dynamic loading/unloading of avatar and animation resources

## 🌐 Browser Compatibility

- **Chrome/Edge** 90+ (WebGPU recommended)
- **Firefox** 90+ (WebGL)
- **Safari** 14+ (WebGL)
- **Mobile** iOS 14+, Android 8+

## 📝 License

MIT License

## 🤝 Contributing

Issues and Pull Requests are welcome!

## 📞 Support

For questions, please contact:
- Email: code@spatialwalk.net
- Documentation: https://docs.spatialreal.ai