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Wired ConnectionsADB Reverse · 60 FPS

Android USB Gaming & ADB

Tournament-grade USB streaming with reverse port tunneling, 48kHz internal game audio, and locked 60 FPS.

6 min read•Last updated October 2026•Source docs
Source Device
Android 8.0+ (Audio requires Android 10+)
Host Receivers
macOS, Windows 10/11, Linux (x86_64)
Protocol
CastSprint Protocol V1 over ADB Reverse
Default Port
TCP 27183 (TCP_NODELAY)
Audio Pipeline
AudioPlaybackCapture 48kHz Stereo
Measured Latency
25 – 35 ms end-to-end

CastSprint’s native Android USB pipeline establishes a local reverse TCP socket over Android Debug Bridge (ADB). This guarantees zero Wi-Fi packet jitter, immunity to crowded router channels, and pure internal game audio capture via Android 10+ AudioPlaybackCapture.

ADB Reverse Tunnel Architecture

Unlike cloud-based screen sharing or Wi-Fi mirrors, the Android stream flows exclusively through the physical USB wire:

Signal Flow
[Android: MediaCodec H.264 Encoder + AudioPlaybackCapture]
         ↓ (Local TCP socket to 127.0.0.1:27183)
[Android ADB Daemon (adbd)]
         ↓ (USB Type-C Cable)
[Host PC ADB Server]
         ↓ (Port 27183 reversed mapping)
[CastSprint Desktop Receiver: Direct3D 11 / Metal / PipeWire]

Enabling USB Debugging by OEM

Before CastSprint can communicate over USB, enable USB Debugging in Android Developer Options. Follow the specific instructions for your manufacturer:

Samsung One UI (Galaxy S / A / Tab)

  1. Open Settings > About phone > Software information.
  2. Tap Build number 7 times until "Developer mode has been enabled" appears.
  3. Return to Settings > Developer options.
  4. Turn on USB debugging.

Xiaomi / Redmi / POCO (HyperOS / MIUI)

  1. Open Settings > About phone.
  2. Tap OS version or MIUI version 7 times.
  3. Go to Settings > Additional settings > Developer options.
  4. Enable USB debugging and USB debugging (Security settings).

Google Pixel / Motorola / Sony (Stock Android)

  1. Open Settings > About phone.
  2. Tap Build number 7 times.
  3. Navigate to Settings > System > Developer options.
  4. Enable USB debugging.

OnePlus / OPPO / Realme (OxygenOS / ColorOS)

  1. Open Settings > About device > Version.
  2. Tap Build number 7 times.
  3. Navigate to Settings > Additional settings > Developer options.
  4. Turn on USB debugging.

USB Gaming vs USB Quick Mirror

CastSprint provides two distinct USB workflows for Android:

Recommended

Android — USB Gaming

  • ✓ Full internal game audio via AudioPlaybackCapture
  • ✓ Hardware MediaCodec 60 FPS locked stream
  • ✓ 6-digit cryptographic session authentication
  • ✓ Sub-35ms tournament latency
  • Requires CastSprint Android companion app
Fallback

Android — USB Quick Mirror

  • ✓ Zero mobile app needed on phone
  • ✓ Native ADB screenrecord stream
  • ✗ Video only (Game audio is unsupported)
  • ✗ ~60–90ms latency
  • Great for quick demonstrations and non-gaming use

Port Forwarding & Connection

CastSprint Desktop automatically attempts to detect your connected Android phone and run reverse port forwarding. If you prefer manual setup or troubleshooting:

  1. Connect your Android phone via USB and allow the RSA debugging prompt.
  2. Verify your device is recognized by running in your terminal:
Terminal
adb devices

Your device should show as device (not unauthorized or offline).

3. Execute the reverse tunnel command:

Terminal
adb reverse tcp:27183 tcp:27183

4. Open CastSprint Android, choose USB (ADB reverse), and tap Start Mirroring. Approve the screen capture prompt.

Internal Game Audio Setup

On Android 10 and newer, CastSprint taps into Google's native AudioPlaybackCaptureConfiguration. This captures mobile game audio directly from apps that allow audio recording, completely bypassing the microphone:

  • No ambient room noise, clicking buttons, or phone vibrations on your stream.
  • Mute your physical phone speaker; internal game audio still streams digitally to PC.
  • Full 48 kHz stereo reproduction with zero distortion.

Android Troubleshooting Checklist

Common ADB Pitfalls
  • "unauthorized" in adb devices: Unplug the USB cable, reconnect, unlock the phone screen, and check "Always allow from this computer" on the popup.
  • App says "Waiting for receiver": Ensure CastSprint Desktop is open and that adb reverse tcp:27183 tcp:27183 succeeded.
  • Micro-stutters: Plug into a rear USB 3.0/3.1 port on your motherboard. Avoid unpowered USB hubs or keyboard passthrough ports.