enricobuehlerandClaude Opus 5
c2a6d30d7b
`AMediaCodec_getInputBuffer` returning null for an index the input-available callback had just handed us dropped both the slot and the access unit on the floor. Every sibling path in this loop recycles the slot — the orphan-part discard and the oversize drop both say so in as many words — because nothing was written and nothing was queued, so it is still ours. Forgetting it leaks one of the codec's input buffers per occurrence: we never use it again and the codec never frees what it never received, so the pipeline runs out of input slots, `pending_aus` overflows into its drop-oldest arm, and the resulting keyframe storm reads as a decode fault rather than a bookkeeping one. The AU went with it, silently — no keyframe request, no freeze gate, unlike every other loss path here — leaving a hole in the reference chain whose concealment was free to reach the screen. Both go back now. `break` rather than `continue`, because a codec that cannot hand out an input buffer it has just advertised is in no state to be fed the rest of the parked queue on this pass, and retrying the same index against every parked AU would burn the whole backlog for nothing; the loop comes round again on the housekeeping wake within 5 ms if it was transient. Gates: cargo ndk check green on arm64 and armv7, fmt clean, Android clippy at the same 4 pre-existing warnings as the base commit. Co-Authored-By: Claude Opus 5 (1M context) <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