BrowserDroid — Android Remote Control via Browser

Stream your Android screen to any browser on your local network and control it with your mouse and keyboard — no apps, no installs, no cables required.

What it does

• Streams your Android screen live to a browser over WebSocket + H264/WebCodecs
• Runs a lightweight HTTPS + WebSocket server directly on the phone (port 8443)
• Accepts touch, swipe, scroll and key input from the browser via an Accessibility Service
• Runs as a foreground service — keeps streaming when you switch apps
• Works over WiFi or with the phone acting as a hotspot
• Uses half-resolution encoding by default (e.g. 1080p → 540p) for smooth local streaming

---

How to build

Requirements

• Android Studio Hedgehog (2023.1) or newer
• Android SDK 34 installed
• A physical Android device (emulators block MediaProjection by default)
• USB debugging enabled on the device

Steps

1. Open Android Studio → Open → select the BrowserDroid folder
2. Wait for Gradle sync to complete
3. Plug in your phone via USB
4. Press Run ▶ (or Shift+F10)
5. Select your device in the deployment dialog

---

First run

1. Tap Start Streaming
2. The system shows: "BrowserDroid will start capturing everything displayed on your screen" → Tap Start now
3. Tap Enable Touch Control and enable BrowserDroid in Android Accessibility Settings
4. Open a browser on a device connected to the same WiFi (or the phone's hotspot)
5. Navigate to the URL shown in the app, e.g. https://192.168.1.x:8443
6. Accept the self-signed certificate warning in your browser
7. Your phone screen appears — click/scroll to control it

---

Project structure

app/src/main/
├── AndroidManifest.xml
├── assets/
│   ├── index.html                          # Browser frontend (WebCodecs player + input)
│   └── BrowserDroid.keystore               # Self-signed TLS cert for HTTPS
└── java/com/example/browserdroid/
    ├── MainActivity.java                   # Permission flow + start/stop UI
    ├── StreamingService.java               # Foreground service — wires everything together
    ├── ScreenEncoder.java                  # MediaProjection → MediaCodec H264 encoder
    ├── FrameBroadcaster.java               # Distributes encoded frames to WebSocket clients
    ├── StreamingServer.java                # NanoHTTPD HTTPS + WebSocket server
    ├── InputController.java                # Translates browser input JSON → gestures
    ├── BrowserDroidAccessibilityService.java  # Dispatches gestures via Accessibility API
    └── NetworkUtil.java                    # Finds the best local IPv4 address

Key classes

StreamingService.java The foreground service that owns all components. Starts the encoder, HTTP server and broadcaster, and wires them together. Stops everything cleanly on destroy.

ScreenEncoder.java Creates a VirtualDisplay mirroring the real screen, feeds it into a MediaCodec H264 encoder, converts Annex B output to AVCC format, and pushes NAL units to FrameBroadcaster. Runs its drain loop on a dedicated background thread.

FrameBroadcaster.java Holds a list of connected WebSocket clients. Caches the latest SPS/PPS config packet so new clients can start decoding immediately without waiting for the next keyframe. Broadcasts every frame to all connected clients.

StreamingServer.java A NanoWSD (NanoHTTPD WebSocket) server listening on port 8443 over TLS. Serves index.html on HTTP GET, and handles two WebSocket endpoints:

• /stream — pushes encoded video frames to the browser
• /control — receives JSON input events from the browser

InputController.java Parses JSON control messages (touch, scroll, key) from the browser and dispatches them as gestures through BrowserDroidAccessibilityService. Normalised 0–1 coordinates are converted to real pixel positions.

BrowserDroidAccessibilityService.java An Android AccessibilityService that can dispatch tap(), swipe() and global actions (back, home, recents) using dispatchGesture().

---

Browser controls

Action	Control
Tap	Left click
Swipe / drag	Click and drag
Scroll	Mouse wheel
Back	Escape or Backspace
Home	F1
Recents	F2

---

Troubleshooting

Problem	Likely cause	Fix
Browser shows certificate warning	Self-signed TLS cert	Click "Advanced" → "Proceed" in your browser
Black / frozen stream	Some OEMs block VirtualDisplay	Try "Disable HW overlays" in Developer Options
Touch does nothing	Accessibility service not enabled	Tap "Enable Touch Control" and enable in Settings
Can't reach the URL	Wrong network	Ensure phone and browser device are on the same WiFi or hotspot
Stream is laggy	Bandwidth or encoding load	Increase the divisor in StreamingService.getScreenMetrics() for lower resolution
Service stops immediately	MediaProjection token expired	The token is one-shot — tap Start Streaming again

---

Configuration

A few constants you may want to tweak:

File	Constant	Default	Effect
StreamingService.java	divisor	2	Stream resolution (1 = full, 2 = half)
ScreenEncoder.java	BIT_RATE	2_000_000	Encoding bitrate in bps
ScreenEncoder.java	FRAME_RATE	30	Target frame rate
ScreenEncoder.java	I_FRAME_INTERVAL	2	Keyframe interval in seconds
StreamingServer.java	PORT	8443	HTTPS / WebSocket port