enricobuehler
12843fe253
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>
88 lines
5.3 KiB
Markdown
88 lines
5.3 KiB
Markdown
# punktfunk host on a Steam Deck
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Run a punktfunk **host** on a Steam Deck — stream its Game Mode (or KDE desktop) *to* other devices.
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(Streaming *to* a Deck is the client; use the Flatpak + [Decky plugin](../../clients/decky/) instead.)
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User-facing guide: **docs-site → "Steam Deck (Host)"** (`docs-site/content/docs/steam-deck-host.md`).
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This README is the deep reference for what the scripts do and how to operate them by hand.
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## Why build on-device (not a package or prebuilt binary)
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SteamOS 3 is an **immutable, read-only Arch** base:
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- No `pacman -S` for system libs; `/usr` is read-only and reset on A/B updates.
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- A **prebuilt binary is fragile** — it links the system FFmpeg/glibc, and a SteamOS update can bump
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those sonames out from under it (the same class of breakage as the NVIDIA-driver-after-update issue).
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- The host needs **unsandboxed** `/dev/uinput` + `/dev/uhid`, PipeWire, the compositor, and VAAPI — so
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Flatpak (the normal Deck app channel) doesn't fit. Flatpak/Decky are for the *client*.
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So the host is built **natively inside a Debian-trixie distrobox** (`pf2`), chosen because its
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FFmpeg/glibc ABI matches SteamOS's — the resulting binary runs **natively on SteamOS** (the container
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is only the build environment; `punktfunk-host` is launched directly, not via `distrobox enter`). A
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rebuild always matches the running OS. Encode is **VAAPI** on the Deck's AMD GPU (NVENC on NVIDIA),
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auto-selected by `PUNKTFUNK_ENCODER=auto`.
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The web console is the one part that stays in the container at runtime: it's a Nitro **`bun`**
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build (`bun` both builds **and runs** it — the bun-preset output uses `Bun.serve` with TLS,
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serving HTTPS (HTTP/1.1 over TLS) with the host's identity cert), so its service does
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`distrobox enter pf2 -- … bun .output/server/index.mjs`. `bun` is provisioned in the container.
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## Scripts
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| Script | What it does |
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|--------|--------------|
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| `install.sh` | Idempotent installer: ensure the `pf2` distrobox + toolchain → build host (+web) → write config → tune sysctl + `input` group (sudo) → install + start `punktfunk-host` / `punktfunk-web` systemd **user** services with linger. |
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| `update.sh` | Rebuild from the current source and restart the services (config + pairings persist). `--pull` does `git pull` first. |
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```sh
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git clone https://git.unom.io/unom/punktfunk ~/punktfunk
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bash ~/punktfunk/scripts/steamdeck/install.sh # PIN pairing required (secure default)
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bash ~/punktfunk/scripts/steamdeck/install.sh --open # trusted LAN: accept unpaired clients
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bash ~/punktfunk/scripts/steamdeck/install.sh --no-web # host only, no web console
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bash ~/punktfunk/scripts/steamdeck/install.sh --no-gamestream # native punktfunk/1 only, no Moonlight surface
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bash ~/punktfunk/scripts/steamdeck/update.sh # after pulling new source
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```
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Note: unlike a bare `serve` (native-only by default), the Deck install enables `--gamestream` by
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default so stock Moonlight clients work out of the box; `--no-gamestream` turns that surface off.
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Env overrides: `PUNKTFUNK_SRC` (source dir, default `~/punktfunk`), `PUNKTFUNK_BOX` (container name,
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default `pf2`), `PUNKTFUNK_MGMT_PORT` (47990), `PUNKTFUNK_WEB_PORT` (3000).
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## What gets installed
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- **Binary:** `~/punktfunk/target-steamos/release/punktfunk-host` (built in `pf2`, run natively).
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- **Config:** `~/.config/punktfunk/host.env` (encoder/compositor) and `web.env` (generated web login
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password + session secret). Trust material (`cert.pem`, `mgmt-token`, `punktfunk1-paired.json`) lives
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here too and persists across updates.
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- **Services:** `~/.config/systemd/user/punktfunk-host.service` (runs `serve --gamestream --mgmt-bind
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0.0.0.0:47990`, `+ --open` if chosen — `--gamestream` adds the Moonlight-compat planes so the Deck's
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Game Mode also streams to stock Moonlight; the native `punktfunk/1` plane is always on) and
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`punktfunk-web.service`. Linger is enabled so they run without a login session.
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- **System tuning (sudo):** `/etc/sysctl.d/99-punktfunk-net.conf` (32 MB UDP buffers — the #1
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high-bitrate lever), `/etc/udev/rules.d/60-punktfunk.rules`, and `$USER` in the `input` group.
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## Operating
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```sh
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systemctl --user status punktfunk-host punktfunk-web
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journalctl --user -u punktfunk-host -f # watch sessions / pairing PIN
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systemctl --user restart punktfunk-host # after editing host.env
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```
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Pair from the web console (Devices → arm pairing) or directly from a client with the host's PIN. The
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host advertises over mDNS as `_punktfunk._udp`, so clients discover it automatically.
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## Gotchas
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- **distrobox required.** If missing: `curl -sfL https://raw.githubusercontent.com/89luca89/distrobox/main/install | sh -s -- --prefix ~/.local` (then ensure `~/.local/bin` is on PATH).
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- **First build is slow** (~10–15 min + ~1 GB toolchain/image). Incremental afterwards.
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- **No passwordless sudo** → the installer skips the sysctl/udev/input steps with a warning; high
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bitrates will drop packets until you apply `99-punktfunk-net.conf` and join `input` yourself.
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- **Game Mode auto-suspend** drops the host off the network on idle — disable it (Settings → Power)
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for a headless host.
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- **WiFi tx ceiling** ≈ 250 Mbps goodput (a Deck hardware/driver packet-rate limit, band-independent);
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fine for 1080p/1440p60. A wired dock lifts it.
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- **After a major SteamOS update**, if the host won't start, run `update.sh` to rebuild against the new
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base libraries.
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