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punktfunk/clients/android
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feat(pf-encode): build against FFmpeg 9
ffmpeg-next 8.1.0 could not accept FFmpeg 9 at all: ffmpeg-sys-next's version probe
covered avcodec majors 56..62 (the range is exclusive of its end), so libavcodec 63 fell
outside what it knew how to bind. 9.0.0 widens that to 56..63, which is what actually
unblocks Arch. Bump both pins — the unconditional Linux dep and the optional Windows
amf-qsv one — and the lock with them.

No API drift to fix. The crate major is a CEILING, not a target: one source tree still
spans FFmpeg 7.x/libavcodec 61, 8.x/62 and 9.x/63 via per-version cfgs, and every wrapper
symbol the NVENC-libav, VAAPI and amf-qsv backends name survives 8.1.0 -> 9.0.0
unchanged. The three hand-written #[repr(C)] hwcontext mirrors are the parts no compiler
checks, so they were re-read against the real headers rather than trusted:
AVCUDADeviceContext and AVD3D11VAFramesContext are byte-identical across 7.1/8/9, and
AVD3D11VADeviceContext gained two trailing UINTs in 8 that 7.1 lacks — which is why that
mirror deliberately stops at the common prefix, and why its assertions now say what they
do and do not buy you. They pin our layout, not libav's; a green build is not evidence.

The CI image is the step that makes this reach users. arch.yml deliberately runs no -Syu
("the image's snapshot IS the build environment"), so the builder stayed frozen on ffmpeg
8 no matter what Arch shipped, and a canary built from that snapshot could not satisfy the
soname dep the PKGBUILD now derives. Re-keying ci/ rebuilds it against ffmpeg 9.

Ubuntu and Windows deliberately stay put: the noble .deb bundles its own FFmpeg 8 behind
an rpath and strips the libav sonames from its Depends, and Windows bundles BtbN DLLs into
the signed installer — neither is exposed to the break, BtbN publishes no FFmpeg 9 build,
and moving either would re-qualify an encode stack to buy nothing.

Verified end to end on 192.168.1.21 (CachyOS, system ffmpeg 2:9.0-5, RTX 5070 Ti): host
builds clean and links libavcodec.so.63/libavutil.so.61/libavfilter.so.12/libswscale.so.10
with no unresolved sonames; the ffmpeg-8 compat shim is gone and the service runs with
NRestarts=0 and answers 401 on :47990; pf-encode's 67 tests pass; and a live synthetic
encode drives real NVENC hardware through FFmpeg 9's libavcodec to a decodable 1080p HEVC
stream (180/180 frames, FEC loopback 0 mismatches) with libavcodec.so.63 and
libnvidia-encode both mapped into the encoding process.
2026-08-08 02:35:20 +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.