enricobuehlerandClaude Fable 5
253e0bbe7c
Wave 1 gave the Android client a mic worth using. It gave it no way to stop talking: leaving the stream, or digging through Settings to turn the whole feature off, were the only ways to stop the room being heard. Now a tap (or Select + Y on a pad) mutes it, and the screen says so while it lasts. How muting gates the capture, and why that way. The AAudio input stream is never stopped: a stop/start would re-run the input-preset fallback ladder and re-prime the buffers on every toggle — hundreds of milliseconds, and possibly a landing on a different rung, silently losing the HAL echo canceller wave 1 went to some trouble to get. Instead the encode loop reads an AtomicBool per 10 ms frame and, while it is set, drains the frame out of its ring and drops it there — the last point before it would have become an Opus packet. Nothing is encoded, nothing is sent, and the realtime capture callback is untouched, so its allocation-free discipline and the queue policy stay exactly as wave 1 verified them. A toggle costs one atomic store and takes effect on the next 10 ms boundary. The frame counter keeps advancing across a mute, because it numbers the captured 10 ms TIMELINE rather than the datagrams. The gap the host then sees is exactly the audio that never came: its de-jitter conceals at most a few frames of it before the pump's 600 ms stale-gap flush resets the chain outright, which is the right reading of a mute. Encoding silence instead would have kept a pointless uplink and a host-side ring alive for its whole duration. Mute is per session and nothing is persisted — a new stream always starts unmuted, and no new setting exists. The flag lives on the session handle rather than on the capture, so the mic stop/start a surface recreate performs brings the user's choice back with it, with no window in which the fresh capture could send an unmuted frame. The control is offered on the evidence that a capture is actually running (nativeMicActive), not on the setting: with the mic disabled, RECORD_AUDIO denied, or every AAudio input rung refused, there is nothing on screen to lie about. On touch it is a pill in the corner the stats HUD doesn't use — the one in-stream control, so it sits above the gesture layer to take its own taps — dim while live, a red "Muted" badge while it isn't. On TV that badge is the indicator alone: Select + Y is the control there, and a focusable button would fight the game for the D-pad. Y is deliberately not one of the exit chord's buttons, so neither chord can be reached through the other. One honest consequence of keeping the stream open: the platform's recording indicator stays lit while muted, because the mic really is still open. What stops is the encode and the send. 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