enricobuehler
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G17's motion half. The docs described what the CLIENT sends and stopped there, which
made a promise the host does not always keep.
The support matrix said a desktop client forwards motion from any pad SDL exposes a gyro
on "and the host injects it into the matching virtual pad". The first clause is true; the
second is only true when the virtual pad has a motion plane. The X-Box 360 and One
backends do not — no gyro in their HID contract — so the host parses every sample and
discards it. That is where *Automatic* lands anything it does not recognise as Sony or
Valve, an 8BitDo with a perfectly good gyro included, and where a Switch Pro lands on a
Windows host with no `hid-nintendo` backend to fold it into.
A reader following the old text would conclude their gyro was broken. The failure has no
other symptom: motion just does nothing.
So both pages now say what to do about it — pick a DualSense-class type — and the
client-settings page says it where the choice is actually made, next to the degrade
paragraph that explains why a session ends up on an X-Box pad in the first place.
The Deck's Steam-Input requirement moves out of Decky's settings blurb, which is the one
place a Deck user streaming FROM the Deck would never look. With Steam Input on, Steam
hands the app its own virtual X-Box pad, so no controller-type choice can help: there is
no gyro on the pad the client can see.
The picker help text now mentions motion on GTK and Android, which is where it was
missing — Windows already said it and Apple says it in its own words. One sentence, the
same sentence, so the four clients answer the question the same way.
This is the doc side of the on-screen notice that shipped earlier in this branch. The two
exist for the same reason and now agree: the client says it when it detects the case, the
docs say it when someone goes looking.
Not covered: the preset COUNTS in note 1 ("Android and the console home offer six …
Windows and Apple offer five") are still unverified against the four pickers, and the
Apple picker's missing Steam Deck entry is a code gap rather than a doc one. Both are
noted in the plan and left for their own change rather than guessed at here.
Gate: Linux CI image fmt + `clippy --locked --all-targets -D warnings` on
punktfunk-client-linux (the GTK string is compiled) plus the core crates and their tests;
Android `:app:compileDebugKotlin` + `:app:testDebugUnitTest`. Green.
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