OpenDisplay

Turn your Android phone into a second monitor for Windows — open source.

OpenDisplay is a complete virtual-display stack:

┌─────────────┐   USB (adb reverse)   ┌──────────────┐
│   Windows    │ ◄──────────────────► │ Android phone │
│  Host + PC  │   HEVC over TCP 27190 │   Receiver    │
└─────────────┘                        └──────────────┘

The host captures a virtual monitor with DXGI Desktop Duplication, encodes it with NVIDIA NVENC (HEVC, low-latency CQP), and streams it over a local TCP tunnel to an Android app that decodes with MediaCodec and renders fullscreen. Touch input on the phone is mapped back to absolute mouse events on Windows.

Features

• True virtual display via UMDF IddCx indirect-display driver (appears as a real monitor in Windows Display Settings)
• Hardware HEVC encoding with NVENC (CQP, ultra-low-latency tuning)
• Cross-adapter GPU copy — works even when the virtual monitor is not on the NVIDIA adapter
• Real cursor overlay drawn from the live Windows cursor (position, shape, alpha)
• Touch → absolute mouse with configurable scaling
• 1080p @ up to 120 Hz (tested: 1920×1080 @ 120 Hz, ~10–20 Mbps)
• All-in-one control panel — plug/unplug monitor, start/stop host, autostart
• No root required on the phone; uses adb reverse for the transport

Components

Component	Path	Description
IddCx driver	driver/OpenDisplayIdd/	UMDF virtual monitor driver (based on RustDeskIddDriver, MS-PL)
Host	host/	DXGI DDA capture → NVENC → TCP server → SendInput
Control panel	control_panel/	Win32 GUI: plug, stream, autostart
Android app	android/	MediaCodec HEVC decoder + touch input
Protocol	proto/opendisplay_proto.h	Shared wire format (handshake, video packets, input)

Requirements

• Windows 10/11 x64
• NVIDIA GPU with NVENC (Kepler or newer)
• Visual Studio 2022 + Windows Driver Kit (WDK)
• Android 8.0+ device with USB debugging
• adb (Android platform-tools)

Build

Driver

cd driver\OpenDisplayIdd
build.cmd

Install (requires test signing):

bcdedit /set testsigning on
:: reboot
install.cmd

Host

cd host
build.cmd

Control panel

cd control_panel
build.cmd

Android app

cd android
gradlew assembleDebug
adb install app\build\outputs\apk\debug\app-debug.apk

Usage

1. Install the driver (see above) — a new display appears in Windows Display Settings.
2. Connect the phone via USB, enable USB debugging.
3. Run opendisplay-control.exe (or opendisplay-host.exe directly).
4. The host sets up adb reverse, launches the app, and starts streaming.
5. The phone shows the virtual desktop. Touch = mouse.

Tap and hold on the phone screen to open settings (FPS, quality, host IP, port).

Protocol (v1)

• Transport: TCP on 127.0.0.1:27190 (tunneled via adb reverse)
• Handshake: 16-byte hello + capabilities (width, height, hz, codec flags)
• Video: HEVC Annex-B, 12-byte header (frame size, PTS, flags for keyframe/config)
• Input: touch (absolute), key, scroll packets

See proto/opendisplay_proto.h for the exact layout.

Credits & licenses

• IddCx driver derived from RustDeskIddDriver (MS-PL)
• IddCx sample from Windows-driver-samples (MIT)
• NVENC headers from nv-codec-headers v12.1 (BSD-3-Clause)
• Touch-to-mouse mapping inspired by scrcpy (Apache-2.0)

Status

v0.1-beta — experimental. Works end-to-end on NVIDIA + Android. Known limitations:

• Requires NVIDIA GPU (NVENC)
• Requires test signing for the driver
• USB/adb only (no wireless yet)
• Cursor overlay is software-composited (minor CPU cost)

License

TBD — pick a license before public redistribution.