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punktfunk/clients/android
enricobuehlerandClaude Opus 5 b297542c4d
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feat(clients/input): controllers can stop being forwarded, for couches that hand the pad over another way
A controller that reaches the host by USB passthrough — VirtualHere and friends, or simply a
pad plugged into the host — arrived there twice: once as the real device, once as the virtual
pad this client built from the same hands. Games read both, so a stick drifts against the
centred second pad and menus take every input twice.

New per-client setting, "Forward controllers", default on (today's behaviour). It is tier-P,
so a profile can decline what another profile forwards.

On Linux and Windows it is deliberately stronger than "send nothing". Opening a controller is
what CLAIMS it — SDL's HIDAPI drivers take the device node — and a claimed device is one a
passthrough tool cannot bind, so with this off the session opens no slot at all and never
enables the Valve HIDAPI drivers. Menu navigation is untouched: the launcher still opens the
active pad, and a session supersedes menu mode whether it forwards or not, so the pad is free
for the whole time a stream is up. The consequence, documented at both the setting and the
chord: the controller escape chord is read off forwarded pads, so it is unavailable there.

The Apple and Android input stacks claim nothing, so those clients keep their slots and their
chords and only gate the wire sends — losing tvOS's only controller way out of a stream would
have been the worse bug. Android does stop its DualSense and Steam Controller 2 USB captures,
which do claim the device.

Surfaces: GTK, WinUI, the console settings screen, Apple's touch and gamepad settings, the
Android touch and gamepad settings, and Decky (which also hides the rows that now have nothing
to act on). Everywhere the "which pad" and "pad type" rows grey out while it is off.

Verified: cargo clippy --all-targets -D warnings + 79 tests on pf-client-core, pf-console-ui,
punktfunk-client-session and punktfunk-client-linux (linux/amd64 container, gate proven
non-vacuous with a planted error); swift build for the Apple clients; gradle compile + 49 unit
tests for Android (likewise proven); tsc for Decky. clients/windows is UNCOMPILED — both
Windows boxes were offline; its edits were reviewed against the helper signatures by hand.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-02 22:21:26 +02:00
..

punktfunk — Android client (phone & TV)

The native Android app for streaming a punktfunk host to your phone, tablet, or Android TV. A Compose app that finds hosts on your network, pairs with a PIN, and streams at the display's own resolution — with hardware HEVC decode, HDR10, and controller support, built for both touch and the couch (D-pad / gamepad focus navigation).

Features

  • Hardware decode — NDK AMediaCodec HEVC → SurfaceView, including HDR10 (Main10 / BT.2020 PQ), with low-latency tuning and a live stats HUD.
  • Audio both ways — Opus + AAudio playback with a jitter ring, plus mic uplink to the host.
  • Controller support — buttons + axes with rumble and HID feedback (lightbar / adaptive triggers); D-pad / gamepad focus navigation for TV and phone.
  • Find hosts automatically — native mDNS discovery; first connect does a one-time SPAKE2 PIN pairing (or TOFU on trusted LANs), then reconnects on a Keystore-wrapped, pinned identity.
  • Compose UI — Connect / Settings / Stream screens with Material You theming.

Built for arm64-v8a + armeabi-v7a + x86_64 — the 32-bit armeabi-v7a slice is what keeps the app installable on the many 32-bit Google TV / Android TV streamers (Walmart onn. 4K, Chromecast with Google TV, budget Amlogic boxes) that otherwise reject a 64-bit-only build as "not compatible".

Get it

Published to Google Play (Internal Testing) — join the beta via the Discord. Per-device setup and pairing: docs.punktfunk.unom.io/docs/install-client.

How it's built — Rust-heavy

Kotlin can't import the cbindgen C header the way Swift can, so a native bridge is unavoidable. We write it in Rust and link punktfunk-core directly — so the Android client reuses the Linux client's orchestration (audio jitter ring, VK keymap inverse, latency/skew math, capture state machine, trust logic) instead of re-porting it into Kotlin.

Side Owns
Rust (native/libpunktfunk_android.so) the JNI seam, NativeClient (QUIC control + UDP data plane), AnnexB → AMediaCodec decode (incl. HDR10), Opus + AAudio audio + mic, controller feedback, latency math, trust/pairing, mdns-sd discovery
Kotlin (app/, kit/) Compose UI, SurfaceView lifecycle, input capture, the Wi-Fi MulticastLock + permission UX, Keystore identity

The single seam is io.unom.punktfunk.kit.NativeBridgeJava_io_unom_punktfunk_kit_NativeBridge_*.

native/           Rust cdylib (workspace member) — links punktfunk-core directly
  src/lib.rs        crate doc · JNI_OnLoad · version probes
  src/session/      session lifecycle: connect/pair + trust, plane start/stop, input shims
  src/decode.rs     AnnexB → AMediaCodec HEVC hardware decode → SurfaceView (incl. HDR10)
  src/audio.rs · src/mic.rs   Opus + AAudio playback / mic uplink
  src/feedback.rs · src/stats.rs   rumble + HID feedback; live video stats
  src/discovery.rs  native mdns-sd browse of the host's _punktfunk._udp advert
app/              :app — Compose UI: Connect / Settings / Stream (phone + TV)
kit/              :kit — NativeBridge · native mDNS discovery · Gamepad · Keymap · Keystore identity

Build & run

Prerequisites: Android SDK + NDK r30 (30.0.14904198), platforms;android-37.0, build-tools;37.0.0, cmake;3.22.1 (builds libopus); JDK 21 (AGP 9.2 runs on JDK 1721, not a newer default); Rust with rustup target add aarch64-linux-android armv7-linux-androideabi x86_64-linux-android and cargo install cargo-ndk. Toolchain is pinned (AGP 9.2 · Gradle 9.4.1 · Kotlin 2.3.21 · Compose BOM 2026.05.01 · compileSdk 37 · minSdk 28).

Android Studio: open clients/android — it uses its bundled JBR 21, and the cargoNdk* task builds the .so as part of the normal build.

CLI (point Gradle at JDK 21 if your machine default is newer):

export JAVA_HOME="$(/usr/libexec/java_home -v 21)"   # or your Temurin 21 path
cd clients/android
./gradlew :app:assembleDebug     # cargo-ndk cross-compiles libpunktfunk_android.so first
./gradlew :app:installDebug      # onto a running emulator/device
# emulators from env setup:  emulator -avd pf_phone   |   emulator -avd pf_tv

The debug APK lands in app/build/outputs/apk/debug/. Launch it, pick a host, pair, and stream.