Technical Architecture of the Emby Platform

1. Emby Server Architecture

1.1 Basic Server Components

Emby Server is built as a multi-tier application with the following main layers:

• Backend Service - Windows Service or Linux Daemon running in background
• Web Server - HTTP server managing client requests
• Database Layer - Database management layer
• API Layer - REST API for communication with clients
• Media Processing - Media processing and transcoding engine

1.2 Technologies and Programming Languages

Emby is developed primarily in C# and .NET, with components in:

• C# .NET for main business logic
• SQLite for embedded databases
• ASP.NET for web server and REST APIs
• FFmpeg for media processing and transcoding
• JavaScript/HTML/CSS for web interface

2. Database System

2.1 Database Structure

Emby uses multiple specialized SQLite databases:

library.db - Main database containing:

• Users Table - users and authentication

• Items Table - metadata for all media elements

• UserData Table - preferences and playback progress

• Images Table - information about associated images

activity.db - Activity logs and statistics devices.db - Records of connected devices channels.db - Data about channels and plugins

2.2 Main Table Schemes

CREATE TABLE Users (
    Id GUID PRIMARY KEY,
    Name NVARCHAR(255) NOT NULL,
    PasswordHash NVARCHAR(255),
    Salt NVARCHAR(255),
    IsAdministrator BIT,
    IsHidden BIT,
    LastLoginDate DATETIME,
    LastActivityDate DATETIME
);

CREATE TABLE TypedBaseItems (
    Id GUID PRIMARY KEY,
    Type NVARCHAR(255),
    Path NVARCHAR(MAX),
    Name NVARCHAR(255),
    Overview TEXT,
    ProductionYear INTEGER,
    PremiereDate DATETIME,
    DateCreated DATETIME,
    DateModified DATETIME
);

CREATE TABLE UserData (
    Id INTEGER PRIMARY KEY AUTOINCREMENT,
    UserId GUID,
    ItemId GUID,
    PlayCount INTEGER,
    IsFavorite BIT,
    PlaybackPositionTicks BIGINT,
    LastPlayedDate DATETIME
);

3. Web Server and REST API

3.1 Web Server Architecture

Emby incorporates an ASP.NET web server that:

• Manages HTTP/HTTPS requests
• Serves web interface and APIs
• Manages authentication and authorization
• Processes media streams

3.2 Main API Endpoints

/api/users - User management

/api/items - Operations on media elements

/api/sessions - Playback session management

/api/library - Library operations

/api/plugins - Plugin management

3.3 Authentication System

Emby uses token-based authentication:

• Access Token is generated at login
• Token is included in request headers
• Each user can have multiple tokens for different devices
• Tokens expire after a configured period

4. Media Processing System

4.1 Transcoding Engine Architecture

Emby integrates FFmpeg for:

• Real-time transcoding for device compatibility
• Metadata extraction from media files
• Thumbnail and chapter generation
• Audio and subtitle processing

4.2 Transcoding Pipeline

Media processing flow:

1. Detection of client device capabilities
2. Analysis of codecs and media containers
3. Source media decoding
4. Processing (rescale, audio transcode, subtitle burning)
5. Encoding in compatible format
6. Streaming to client

5. Plugin and Extensions System

5.1 Plugin Architecture

Emby supports plugins developed in C# that can:

• Add new metadata providers
• Extend web interface with new functionalities
• Add additional media formats
• Integrate with external services

5.2 Plugin Structure

A typical Emby plugin contains:

• .NET DLL assembly with business logic
• Configuration files
• Web resources (JavaScript, CSS, images)
• Manifest with plugin metadata

6. Network and Communication System

6.1 Communication Protocol

Emby uses multiple protocols:

• HTTP/HTTPS for API and web interface
• WebSockets for real-time notifications
• UDP for discoverability on local network
• RTSP/HTTP for media streaming

6.2 Automatic Network Discovery

The service uses SSDP (Simple Service Discovery Protocol) for:

• Announcing server presence on network
• Automatic discovery by clients
• Quick connection configuration

7. Cache and Performance System

7.1 Cache Layer

Emby implements multiple cache levels:

• Image cache (posters, backdrops)
• Metadata cache for search performance
• API result cache
• Web resource cache

7.2 Performance Optimizations

Techniques used for performance:

• Aggressive indexing in databases
• Pagination for large results
• Compression for data transfer
• Load balancing for multiple requests

8. Security System

8.1 Implemented Security Measures

Emby includes:

• Token-based authentication
• Role-based authorization
• Input validation to prevent attacks
• Extensive logging for audit
• Options for HTTPS and certification

9. Server Initialization Process

9.1 Startup Sequence

At startup, Emby Server executes:

1. Configuration initialization from XML files
2. Connection to SQLite databases
3. Loading installed plugins
4. Scanning configured media libraries
5. Starting web server and network services
6. Announcing presence on local network