# Real-time recording

> Enable real-time recording in your Vivox project.

## Overview

Real-time recording is a feature designed to stream data in real time from the Vivox backend to external services. By leveraging Vivox real-time recording, developers can capture voice data for purposes such as analytics, moderation, or storage.

## Get started

To get started with Vivox real-ime recording reach out to your technical account manager or create a [ticket](https://support.unity.com/hc/en-us/requests/new?ticket_form_id=360003199531) to request the feature for your project.

## Websocket specification

In order to accept real-time recording data, your service must implement a websocket server that can handle incoming connections from the Vivox real-time recording service.

### Set up the websocket connection

When establishing a websocket connection, your server must validate the authentication token sent in the `Authorization` header. Once you have a token and WSS endpoint you must provide it to your technical account manager to configure the Vivox real-time recording service to connect to your websocket server.

## Data flow

All audio is delivered in 15 second chunks. You will receive two types of messages via a websocket connection:

1. Metadata messages: These messages contain information about the file, such as User URI, channel URI, timestamp, and other relevant metadata.
2. Audio data messages: These messages contain the actual audio data in `OGG` format with 15 seconds of audio data.

Immediately following each metadata message, you will receive a binary audio data message containing the corresponding audio data.

The following diagrams shows the sequence of events and information flow between the real-time recording service and your service:


**Frame:**
```mermaid
sequenceDiagram
    participant WSServer as Real Time Recording
    participant External as Your Service

    Note over WSServer,External: Cycle 1: Sent at T+0s<br/>(Contains 15 seconds of audio data)
    
    WSServer->>External: 1. Send Metadata Message (JSON)
    Note over External: User ID, Channel ID, Timestamp, etc.
    
    WSServer->>External: 2. Send Audio Data (OGG Binary)
    Note over External: 15-second audio chunk
    
    Note over WSServer,External: 15 seconds elapse (T+0s to T+15s)
    Note over WSServer,External: Cycle 2: Sent at T+15s<br/>(Contains next 15 seconds of audio data)
    
    WSServer->>External: 1. Send Metadata Message (JSON)
    Note over External: User ID, Channel ID, Timestamp, etc.
    
    WSServer->>External: 2. Send Audio Data (OGG Binary)
    Note over External: Next 15-second audio chunk

```

### JSON metadata message format

The metadata message is sent as a JSON object with the following structure:

```json
{
  "type": "metadata",
  "timestamp": 1705270000, // Unix timestamp indicating the start of the 15-second interval the audio belongs to
  "speaker": "sip:.issuer.alice.@domain.vivox.com", // The user the audio belongs to
  "listeners": ["sip:.issuer.bob.@domain.vivox.com", "sip:.issuer.charlie.@domain.vivox.com"], // List of users who heard the speaker
  "channel": "sip:confctl-g-issuer.general-chat@domain.vivox.com", // Channel the audio was spoken into
  "muted": false, // Indicates if the speaker was muted during this interval
  "kicked": false // Indicates if the speaker was kicked from the channel during this interval.
}
```

### OGG audio format specification

All audio data is delivered in OGG Opus format with the following specifications:

| Property             | Value    |
| -------------------- | -------- |
| **Container Format** | Ogg      |
| **Audio Codec**      | Opus     |
| **Channels**         | 1 (Mono) |
| **Channel Layout**   | Mono     |
| **Sample Rate**      | 48 kHz   |
| **Compression**      | Lossy    |

### Join and leave events

Join and leave events are sent as JSON objects with the following structure:

```json
{
   "type":"join",
   "timestamp":1677610000, // This timestamp is the time the user joined the channel NOT the minute interval like the audio data
   "speaker":"sip:.alice.my-issuer.@domain.com",
   "channel": "sip:confctl-g-my-issuer.mychannel1@domain.vivox.com"
}
```

```json
{
   "type":"leave",
   "timestamp":1677610000, // This timestamp is the time the user joined the channel NOT the minute interval like the audio data
   "speaker":"sip:.alice.my-issuer.@domain.com",
   "channel": "sip:confctl-g-my-issuer.mychannel1@domain.vivox.com"
}
```