Files
punktfunk/clients/linux
enricobuehler 12843fe253 feat(protocol,clients): codec preference negotiation + Linux client decodes per Welcome (Phase 2a)
Adds a client-selectable **preferred codec** and wires the core + ABI + probe + Linux client to
negotiate and decode it. (Windows/Apple/Android follow in 2b.)

**Core:**
- `Hello.preferred_codec` (a single CODEC_* bit, 0 = auto) — a soft hint appended after
  `video_codecs`. `resolve_codec(client, host, preferred)` now honors the preference when the host
  can also emit it, else falls back to precedence (HEVC > AV1 > H.264). Roundtrip + preference tests.
- `NativeClient::connect` takes `video_codecs` + `preferred_codec`; `NativeClient.codec` exposes the
  resolved `Welcome.codec`.
- ABI: `punktfunk_connect_ex7` (adds the two codec params; `ex6` delegates to it advertising
  HEVC-only) + `punktfunk_connection_codec` getter + `PUNKTFUNK_CODEC_{H264,HEVC,AV1}` constants
  (drift-guarded against the wire values). Header regenerated.

**Host:** passes `hello.preferred_codec` into `resolve_codec`.

**probe:** `--codec h264|hevc|av1|auto` sets the preference (still advertises it can decode all
three); the dump extension already follows the resolved codec.

**Linux client:** advertises the codecs FFmpeg can actually decode (`decodable_codecs()`), threads
the user's `codec` setting as the preference, and builds the decoder — both the software and VAAPI
paths, plus the mid-session VAAPI→software demotion — from the negotiated `Welcome.codec` instead of
hardcoding HEVC. New "Video codec" dropdown in Preferences (Automatic/HEVC/H.264/AV1).

Live-validated on the dev box: probe `--codec hevc` against a software (H.264-only) host resolves to
H.264 (graceful soft-preference fallback), no failure. clippy + core (57) + host (133) tests green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-02 00:13:26 +00:00
..

punktfunk — Linux client

The native Linux app for streaming a punktfunk host to your desktop, laptop, or Steam Deck. It's a clean GTK4/libadwaita app that finds hosts on your network, pairs with a PIN, and puts a low-latency stream on glass at your display's own resolution and refresh rate.

Built in Rust, it links the shared punktfunk-core directly (no C ABI) and speaks the fast punktfunk/1 protocol — QUIC control plane, GF(2¹⁶) FEC + AES-GCM data plane.

Features

  • Zero-copy hardware decode — FFmpeg VAAPI decode → DRM-PRIME dmabuf → GdkDmabufTexture (Tier-1 zero-copy on Intel and AMD), with an automatic software-HEVC fallback on NVIDIA or when VAAPI is unavailable.
  • Your display's native mode — the host builds a virtual output at exactly your WxH@Hz; no scaling, no letterboxing. Steady 60 fps at 1080p60, ~6 ms capture→decoded on the LAN.
  • Audio both ways — PipeWire playback with a jitter ring, plus mic uplink to the host.
  • Full controller support — SDL3 gamepads with rumble and DualSense fidelity (lightbar, player LEDs, touchpad, motion, adaptive-trigger replay). Click-to-capture keyboard and mouse, with a release chord (Ctrl+Alt+Shift+Q) and focus-loss release.
  • Find hosts automatically — mDNS discovery lists hosts on your LAN; saved hosts persist. First connect does a one-time SPAKE2 PIN pairing (or TOFU on trusted LANs), then reconnects on a pinned identity.
  • Per-host speed test to pick a bitrate, plus compositor and mode preferences in Settings.

Get it

Most people should install a package rather than build from source:

Distro Install
Flatpak (any distro, Steam Deck) io.unom.Punktfunk — see packaging/flatpak
Ubuntu / Debian (apt) sudo apt install punktfunk-client (after adding the repo)
Fedora / Bazzite (rpm) rpm-ostree install punktfunk-client
Arch (PKGBUILD) see packaging/arch

Per-device install steps and pairing walkthrough: docs.punktfunk.unom.io/docs/install-client.

Build & run from source

Requires GTK ≥ 4.16, libadwaita ≥ 1.5, FFmpeg 7 or 8 (with VAAPI for hardware decode), PipeWire, and SDL3 (with hidapi) development packages.

# from the repo root
cargo run -p punktfunk-client-linux                 # launch the app
cargo run -p punktfunk-client-linux -- --discover   # list hosts on the LAN, then exit
cargo run -p punktfunk-client-linux -- --connect HOST[:PORT]   # skip the host list and connect

The binary is named punktfunk-client. Handy flags: --connect host[:port] (start a session immediately — for scripting and the Steam Deck launcher), --discover [secs], and --pair <PIN> --connect host[:port] (run the pairing ceremony headlessly). Force a decoder with PUNKTFUNK_DECODER=software|vaapi.

Layout

src/
  main.rs · app.rs        entry point, GTK application, CLI paths
  ui_hosts.rs             host list (mDNS + saved), pairing / trust dialogs
  ui_settings.rs          resolution · refresh · decoder · bitrate · compositor · mic
  ui_stream.rs            the stream window (GtkGraphicsOffload present) + input capture
  session.rs              session lifecycle over the NativeClient connector
  video.rs                FFmpeg VAAPI / software decode → dmabuf / texture
  audio.rs                PipeWire playback + mic uplink
  gamepad.rs · keymap.rs  SDL3 controllers + feedback; keyboard VK mapping
  trust.rs · discovery.rs persistent identity, TOFU/PIN pairing, mDNS browse
tools/screenshots.sh      store screenshot capture