enricobuehler
2621b6e6b1
The 2026 Steam Controller (Valve "Ibex" / SDL "Triton") captured on an Android client is passed through AS-IS: the host presents a virtual pad with the real wired identity (28DE:1302) and mirrors the physical pad's raw HID reports, so Steam on the host drives it over hidraw exactly like the real thing — trackpads, gyro, paddles, and its rumble/settings writes flow back onto the physical controller. Protocol ground truth: SDL's Valve-maintained SDL_hidapi_steam_triton.c + steam/controller_structs.h. Core: - GamepadPref::SteamController2 (wire byte 9; names steamcontroller2/ sc2/ibex) + PUNKTFUNK_GAMEPAD_STEAMCONTROLLER2 in the C ABI. - Raw HID planes: RichInput::HidReport (0xCC/0x04, client→host input reports verbatim, Copy fixed-64 body) and HidOutput::HidRaw (0xCD/0x05, host→client feature/output writes for replay). Best-effort is sound by the device protocol's own design (rumble re-sent every ~40 ms, settings every ~3 s — losses self-heal); HidRaw bypasses hidout dedup for exactly that reason. Host (Linux): - triton_proto.rs + steam_controller2.rs: Triton2Manager UHID backend — no kernel driver binds the PID (hidraw only; Steam Input is the consumer), raw mirroring with a typed-fallback 0x42 synthesizer until the first raw report, SET_REPORT ack + raw forward, canned GET_REPORT serial reply, rumble also parsed onto the universal 0xCA plane (phone mirror). Rides the uhid + 28DE-conflict degrades; UHID promotion by Steam is flagged in the creation log (usbip transport is the known follow-up if Steam ignores Interface:-1 devices for Triton too). Android: - Sc2UsbLink (wired/Puck: vendor-interface claim detaches the OS driver, interrupt read loop, lizard-off on the watchdog cadence, raw replay via interrupt-OUT / SET_REPORT with hidapi report-id framing) and Sc2BleLink (Valve vendor GATT service, notify subscribe machine, 0x45 re-framing, HIGH connection priority). - Sc2Capture orchestrator: raw plane + typed mirror (exit chord + host degrade paths keep working) on a GamepadRouter external slot; raw return path via GamepadFeedback.onHidRaw. - nativeSendPadHidReport JNI (direct ByteBuffer, no per-report copy), hidout raw decode, usb-host/BLUETOOTH_CONNECT manifest bits, opt-out settings toggle, StreamScreen engagement incl. the USB permission flow. Verified: core 149 + host 312 tests green on Linux (.21), on-box uhid smoke creates/mirrors/tears down the virtual 28DE:1302, C ABI harness round-trips, Android compileDebugKotlin green. On-glass with the real controller owed. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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
AMediaCodecHEVC →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.NativeBridge ⇄ Java_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 17–21, 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.
Related
- Documentation — quick start, pairing, troubleshooting
- Project README — the host, the other clients, and how it all fits together