AudioShare USB Custom

Stream all Windows system audio to an Android phone speaker over a USB ADB connection. This fork is being specialized for a portable, standard-user, firewall-independent Windows workflow.

Download and use it

For non-developers, start with the beginner guide. The release page publishes one standalone Windows ZIP containing the EXE, bundled ADB, and matching companion APK:

Download AudioShare USB for Windows

Ask an AI assistant to guide you

You can give an AI assistant the two repository links below and ask it to walk you through setup one step at a time. The repositories include an explicit AI setup brief so the assistant knows that an ordinary user should download the portable Windows ZIP—not clone source code or open Android Studio.

Copy and send this prompt:

Help me set up AudioShare USB as a beginner, one step at a time. I want my
Android phone to play all ordinary Windows audio through a USB cable. Use the
ready-made portable Windows release, not a source build. Read these projects
and their AI setup instructions before guiding me:
https://github.com/CodeinScrubs/AudioShare
https://github.com/CodeinScrubs/AudioShare-Android

Development status: the Android companion passes clean unit, lint, debug, and permanently signed release builds. A real Android 16 emulator passed a cold-install, authenticated ADB-forwarded stream with enforced speaker route, wake-lock continuity, and exact cleanup. Headless virtual audio can underrun, so the current Android hardening pass treats zero-drop timing as a physical-device gate. The Windows capture hierarchy passes strict native integration in global, multi-endpoint, and default-output modes with non-zero PCM. Flutter analysis and 39 supervisor/lifecycle/security/persistence tests pass. RC4 also reports Windows capture signal level and Android playback progress, journals exact AudioShare-owned ADB forwards for crash recovery, shows a visible warning when the phone media volume is muted or very low, and stops with a clear instruction instead of reconnecting if phone-local media takes Android audio focus. The complete audible path is now hardware tested on a Samsung Galaxy A52s with Android 14: global-system capture, a 10 ms host queue high-water mark, and zero visible host/Android drops in the initial run. Screen-off endurance, repeated USB recovery, measured latency, restricted-PC checks, and the two-hour run remain stable-release gates. See hardware results and POC results.

Architecture

all ordinary Windows applications and system sounds
                -> global process loopback (preferred)
                -> active-endpoint loopback + bounded mixer (legacy fallback)
                -> default-output loopback (last-resort fallback)
                -> 48 kHz stereo PCM16
                -> outbound 127.0.0.1 connection
                -> ADB forward over USB
                -> installed Android companion
                -> AudioTrack
                -> phone speaker

The Windows program creates no listening audio socket. Automatic mode rejects Wi-Fi ADB and emulators. The Android companion declares no INTERNET permission. No virtual audio driver, firewall rule, LAN, Wi-Fi, Internet, installer, Windows service, or administrator elevation is intentionally required at runtime.

On supported Windows builds, AudioShare uses Microsoft's virtual process-loopback device in exclude mode: it captures the global system mix except AudioShare's own process tree, independent of physical render endpoint. If that feature probe fails, it enumerates usable active render endpoints, captures each with event-driven WASAPI loopback, and mixes them on a bounded 10 ms clock. If no endpoint can be opened, it falls back to the current default output. The UI identifies the active mode and endpoint count. The multi-endpoint path has independent device clocks, so it favors bounded live-edge latency and reports drops/underruns; its strict local stress run had zero host/ring drops, while long-run drift and duplicate mirrored-output suppression still require target-hardware evidence.

First time only

1. Extract the complete Windows package to a normal user-writable folder.
2. Enable Android Developer Options and USB debugging.
3. Connect the phone with a data-capable USB cable.
4. Unlock the phone and approve Allow USB debugging? for this computer.
5. Start AudioShare. If exactly one authorized USB phone is present, it is selected automatically; with multiple phones, choose the intended one.
6. If shown, choose Install companion. This is an explicit one-time ADB APK installation; AudioShare never silently installs an app in the background.
7. After installation, the host verifies that the installed base APK exactly matches the bundled artifact, launches it, creates the USB-local transport, authenticates it, and starts capture automatically. If the phone already has a newer companion than this portable host supports, AudioShare asks for a newer Windows build instead of attempting a downgrade.
8. Confirm that system audio plays through the phone and leave automatic connection enabled.

The PC must already have a working Android USB/ADB driver. Installing a missing driver can require administrator access and is outside AudioShare's control.

Daily use target

1. Start AudioShare after logging in to Windows.
2. Plug in the remembered, authorized phone by USB.
3. Play sound from any Windows application, including Infinit/idplayer.

While AudioShare is using the phone as the PC speaker, do not start a separate music or video stream directly on the phone. Android gives that local app audio focus, so AudioShare stops once and asks you to stop the phone-local media and click Connect again. It does not enter an automatic reconnect loop.

Once the Windows host is open, the intended workflow requires no Android UI, IP address, Wi-Fi, Internet, firewall approval, or Connect click. Automatic Windows startup and tray UI are not implemented yet. The zero-click USB supervisor is unit tested but not yet verified across a target-phone reconnect. A deliberate Disconnect stops the current session but keeps the preferred phone remembered; it stays disconnected while that cable session remains, and unplug/replug restores the normal automatic path.

If the same failure happens three times in one minute, automatic retries stop and AudioShare shows the exact error with a manual retry path. This prevents a permanent “Connecting” loop for broken packages, unsupported capture, or a device policy that cannot recover by itself.

Build from source

The tested host toolchain is Flutter 3.47.2 / Dart 3.13.2 and Visual Studio 2022 or newer with Desktop C++. From client:

flutter pub get
flutter gen-l10n
flutter analyze
flutter test
flutter build windows --debug

Debug builds bundle the clearly labeled version-code 7 debug companion APK. A distributable release must use a stable signing key and provide both the signed APK and its pinned signer-certificate SHA-256 explicitly. Configuration fails unless Android SDK apkanalyzer and apksigner confirm the signature, exact certificate, package ID, and exact host-compatible version:

$env:AUDIOSHARE_COMPANION_APK = 'C:\absolute\path\audioshare-companion.apk'
$env:AUDIOSHARE_COMPANION_CERT_SHA256 = '<64 hex digits from apksigner --print-certs>'
flutter build windows --release
..\tools\package_windows_release.ps1 `
  -BundleDirectory .\build\windows\x64\runner\Release `
  -OutputZip .\build\AudioShare-Windows.zip

The packaging script checks every manifest hash, tests the ZIP after extraction to a path containing spaces, and proves that missing or altered files are rejected. It writes the archive SHA-256 beside the ZIP.

Public tags are assembled by the release workflow from the pinned companion in client/companion-release.json. The companion's package, release signature, certificate, version, debug state, and permission allowlist are verified before the Windows package is built. Windows binaries are portable but not Authenticode signed; users may therefore see Microsoft SmartScreen reputation warnings.

The sibling client android app Git repository owns the native companion:

cd '..\client android app'
$env:JAVA_HOME = 'C:\Program Files\Android\Android Studio\jbr'
.\gradlew.bat testDebugUnitTest lintRelease assembleRelease `
  --no-daemon --max-workers=1

The upstream com.ysbing.audioshare Android server, its public default signing key, and its stale APK are retired from this branch. They are not compatible with or trusted by the USB companion. See security policy.

Additional native protocol check:

g++ -std=c++17 -Wall -Wextra -Werror client/native/wire_protocol_test.cpp

The native system-capture integration harness uses a fake local companion. It verifies activation, handshake, 48 kHz PCM flow, and non-zero signal without an Android device; the fake listener exists only inside the test executable:

g++ -std=c++17 -Wall -Wextra -Werror -shared client/native/audio_capture.cpp `
  -o audio_capture.dll -lmmdevapi -lole32 -lws2_32 -lwinmm -luuid
g++ -std=c++17 -Wall -Wextra -Werror `
  client/native/system_capture_integration_test.cpp `
  -o system_capture_integration_test.exe -lws2_32
.\system_capture_integration_test.exe --require-signal --expect-global
.\system_capture_integration_test.exe --expect-handshake-retry
.\system_capture_integration_test.exe --expect-handshake-stop
.\system_capture_integration_test.exe --expect-handshake-error
.\system_capture_integration_test.exe --expect-disconnect-error
# Compatibility branch checks (test-only compile flags):
# -DAUDIOSHARE_FORCE_MULTI_ENDPOINT  -> --expect-multi
# -DAUDIOSHARE_FORCE_DEFAULT_ENDPOINT -> --expect-default

Documentation

• Selected companion architecture
• Wire protocol
• Evidence and POC results
• Layered troubleshooting
• Manual test plan
• Physical-device results
• Pinned upstream baseline

License

Licensed under LGPL-3.0-or-later. Bundled Android platform-tools notices are preserved in client/assets/platform-tools-NOTICE.txt and copied into Windows distributions.

AudioShare USB custom edition was created by Shayan SalehiRad.