Windows Host Setup

Overview

The Windows host is a C++/Go application that:

Captures video using Windows Graphics Capture (WGC)
Encodes video with FFmpeg hardware acceleration (NVENC/QSV/AMF)
Captures audio via WASAPI
Streams media over WebRTC using Pion
Receives input from clients via WebRTC DataChannels

Requirements

System Requirements

Windows 10 version 1903 (May 2019 Update) or later is required for WGC support.

OS: Windows 10 (1903+) or Windows 11
CPU: Modern multi-core processor (4+ cores recommended)
GPU: NVIDIA (GTX 900+ series), Intel (6th gen+), or AMD with hardware encoding
RAM: 4 GB minimum, 8+ GB recommended
Network: Low-latency connection (5+ Mbps upload per stream)

Development Tools

Visual Studio 2019 or 2022
- Desktop development with C++ workload
- Windows 10 SDK (10.0.17134.0 or later)
- Platform Toolset v141, v142, or v143
Go 1.19 or later (for WebRTC stack)
FFmpeg with hardware encoding support

Building the Host

Clone the repository

git clone <repository-url>
cd source

Open the Visual Studio solution

Open DisplayCaptureProject.sln in Visual Studio.The project supports multiple configurations:

Debug|x64: Development build with debug symbols
Release|x64: Optimized production build

Only x64 (64-bit) builds are supported. Win32 (32-bit) is not supported.

Restore NuGet packages

Visual Studio should automatically restore the required packages:

Microsoft.Windows.CppWinRT (2.0.220531.1)
Windows 10 SDK references

If packages don’t restore automatically:

Right-click solution → Restore NuGet Packages

Build the solution

Build → Build Solution (Ctrl+Shift+B)

Or from the command line:

msbuild DisplayCaptureProject.sln /p:Configuration=Release /p:Platform=x64

The executable will be output to:

Debug: x64\Debug\DisplayCaptureProject.exe
Release: x64\Release\DisplayCaptureProject.exe

Configuration

config.json Setup

The host reads configuration from a config.json file that must be placed in the same directory as the executable.

{
  "host": {
    "targetProcessName": "YourGame.exe",
    "signalingUrl": "ws://localhost:3002",
    "matchmaker": {
      "url": "http://localhost:3000",
      "hostSecret": "HELLO-MFS",
      "heartbeatIntervalMs": 20000
    },
    "window": {
      "resizeClientArea": true,
      "targetWidth": 1920,
      "targetHeight": 1080
    },
    "video": {
      "fps": 60,
      "bitrateStart": 8000000,
      "bitrateMin": 8000000,
      "bitrateMax": 12000000,
      "preset": "p2",
      "rc": "cbr"
    },
    "audio": {
      "processLoopback": {
        "enabled": true,
        "includeProcessTree": true
      },
      "bitrate": 80000
    },
    "input": {
      "blockWinKeys": true,
      "releaseAllOnDisconnect": true,
      "injectionPolicy": "REQUIRE_FOREGROUND"
    }
  }
}

Key Configuration Options

Host Settings

Field	Type	Description	Default
`targetProcessName`	string	Name of the game/application to capture	Required
`signalingUrl`	string	WebSocket URL of signaling server	Required
`matchmaker.url`	string	HTTP URL of matchmaker service	Required
`matchmaker.hostSecret`	string	Shared secret for host authentication	`HELLO-MFS`
`matchmaker.heartbeatIntervalMs`	number	Heartbeat interval to matchmaker (ms)	`20000`

Window Settings

Field	Type	Description	Default
`window.resizeClientArea`	boolean	Resize game window to target dimensions	`true`
`window.targetWidth`	number	Target window width	`1920`
`window.targetHeight`	number	Target window height	`1080`

Video Encoding

Field	Type	Description	Default
`video.fps`	number	Target framerate	`60`
`video.bitrateStart`	number	Initial bitrate (bps)	`8000000`
`video.bitrateMin`	number	Minimum bitrate for ABR (bps)	`8000000`
`video.bitrateMax`	number	Maximum bitrate for ABR (bps)	`12000000`
`video.preset`	string	NVENC preset (`p1`-`p7`, lower=faster)	`p2`
`video.rc`	string	Rate control mode (`cbr`, `vbr`)	`cbr`
`video.bf`	number	B-frames (0 for lowest latency)	`0`

For ultra-low latency: use preset: "p1", rc: "cbr", bf: 0For better quality at higher latency: use preset: "p4", rc: "vbr", bf: 2

Audio Capture

Field	Type	Description	Default
`audio.processLoopback.enabled`	boolean	Capture only target process audio (Win11+)	`false`
`audio.bitrate`	number	Opus bitrate (bps)	`80000`
`audio.enableFec`	boolean	Enable forward error correction	`true`
`audio.complexity`	number	Opus complexity (0-10)	`6`

Input Injection

Field	Type	Description	Default
`input.blockWinKeys`	boolean	Block Windows key during session	`true`
`input.releaseAllOnDisconnect`	boolean	Release all keys on disconnect	`true`
`input.injectionPolicy`	string	`REQUIRE_FOREGROUND` or `ALLOW_BACKGROUND`	`REQUIRE_FOREGROUND`
`input.maxInjectHz`	number	Max input rate (events/sec)	`10000`

Running the Host

Start the game or application

Launch the target application specified in config.json as targetProcessName.

# Example
.\YourGame.exe

Run the host executable

Ensure config.json is in the same directory, then run:

cd x64\Release
.\DisplayCaptureProject.exe

The host will:

Connect to the matchmaker and register itself
Send heartbeats every 20 seconds
Wait for client connections
Begin capturing and streaming when a client connects

Startup Logs

You should see output similar to:

[INFO] Loading config.json
[INFO] Target process: YourGame.exe
[INFO] Connecting to matchmaker: http://localhost:3000
[INFO] Registered with matchmaker, hostId: abc-123-def
[INFO] Connected to signaling server: ws://localhost:3002
[INFO] Waiting for client connection...

Troubleshooting

Build Errors

Error: Windows SDK not found

Solution: Install the Windows 10 SDK via Visual Studio Installer

Visual Studio Installer → Modify → Individual Components
→ Search "Windows 10 SDK" → Select latest version → Modify

The project requires Windows SDK 10.0.17134.0 or later.

Error: C++/WinRT package not found

Solution: Restore NuGet packages

# From Visual Studio
Tools → NuGet Package Manager → Package Manager Console
Update-Package -reinstall

# Or from command line
nuget restore DisplayCaptureProject.sln

Error: Cannot open include file 'winrt/...'

Solution: The CppWinRT package is not properly installed

Delete the 'packages' folder
Right-click solution → Restore NuGet Packages
Clean and rebuild solution

Runtime Errors

Error: Target process not found

The host cannot find the game executable specified in targetProcessName.Solutions:

Ensure the process name matches exactly (case-sensitive)
Launch the game before starting the host
Use Task Manager to verify the exact process name
For UWP games, use the package family name

Error: Failed to connect to matchmaker

Solutions:

Verify the matchmaker is running
Check matchmaker.url in config.json
Verify hostSecret matches the matchmaker’s HOST_SECRET
Check firewall rules

Error: Graphics capture failed

WGC (Windows Graphics Capture) initialization failed.Solutions:

Update Windows to version 1903 or later
Update GPU drivers
Enable “Graphics Capture” in Windows Settings
Run as Administrator if capturing elevated processes

Error: Hardware encoder not available

FFmpeg cannot initialize NVENC/QSV/AMF.Solutions:

Update GPU drivers
Verify GPU supports hardware encoding:
- NVIDIA: GTX 900 series or newer
- Intel: 6th gen (Skylake) or newer
- AMD: VCE 1.0 or newer
Check GPU is not fully utilized by other applications

Performance: High CPU usage

Solutions:

Lower video.fps (try 30 instead of 60)
Use faster NVENC preset (p1 or p2)
Reduce resolution in window.targetWidth/Height
Enable capture.skipUnchanged: true
Set capture.mmcss.enable: true for thread priority boost

Performance: High latency

Solutions:

Use CBR rate control: video.rc: "cbr"
Disable B-frames: video.bf: 0
Use fastest preset: video.preset: "p1"
Reduce video.pacingFixedUs for faster frame pacing
Enable audio.latency.strictLatencyMode: true

Production Deployment

Running as a Windows Service

For production, run the host as a Windows service using NSSM or similar:

# Install NSSM
choco install nssm

# Create service
nssm install CloudGamingHost "C:\path\to\DisplayCaptureProject.exe"
nssm set CloudGamingHost AppDirectory "C:\path\to"
nssm set CloudGamingHost DisplayName "CloudGaming Host Service"
nssm set CloudGamingHost Start SERVICE_AUTO_START

# Start service
nssm start CloudGamingHost

Security Hardening

For production deployments:

Run the host in a dedicated user account with minimal permissions
Use Windows Firewall to restrict outbound connections
Change hostSecret to a strong random value
Use WSS (secure WebSocket) for signaling
Monitor logs for suspicious activity
Keep Windows and GPU drivers updated

Monitoring

Key metrics to monitor:

CPU usage: Should be under 50% for good performance
GPU usage: Encoder should be under 80%
Network upload: Matches configured bitrate
Frame drops: Should be near zero
Matchmaker heartbeats: Should succeed every 20 seconds

Next Steps

Signaling Server Deployment - Set up the WebRTC signaling infrastructure
Matchmaker Deployment - Configure host registration service
Client Deployment - Deploy the browser client

Getting Started

Deployment

Components

Configuration

Operations

Overview

Requirements

System Requirements

Development Tools

Building the Host

Configuration

config.json Setup

Key Configuration Options

Host Settings

Window Settings

Video Encoding

Audio Capture

Input Injection

Running the Host

Startup Logs

Troubleshooting

Build Errors

Runtime Errors

Production Deployment

Running as a Windows Service

Security Hardening

Monitoring

Next Steps

Build docs developers (and LLMs) love

Getting Started

Deployment

Components

Configuration

Operations

Documentation Index

​Overview

​Requirements

​System Requirements

​Development Tools

​Building the Host

​Configuration

​config.json Setup

​Key Configuration Options

​Host Settings

​Window Settings

​Video Encoding

​Audio Capture

​Input Injection

​Running the Host

​Startup Logs

​Troubleshooting

​Build Errors

​Runtime Errors

​Production Deployment

​Running as a Windows Service

​Security Hardening

​Monitoring

​Next Steps

Build docs developers (and LLMs) love

Overview

Requirements

System Requirements

Development Tools

Building the Host

Configuration

config.json Setup

Key Configuration Options

Host Settings

Window Settings

Video Encoding

Audio Capture

Input Injection

Running the Host

Startup Logs

Troubleshooting

Build Errors

Runtime Errors

Production Deployment

Running as a Windows Service

Security Hardening

Monitoring

Next Steps