punktfunk/clients/linux/README.md

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

Related

• Documentation — quick start, pairing, troubleshooting
• Steam Deck plugin — launches this client fullscreen in Gaming Mode
• Project README — the host, the other clients, and how it all fits together