punktfunk/docs-site/content/docs/configuration.md

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Configuration	Every host.env setting and PUNKTFUNK_* environment variable — compositor, video, input, gamepads, tuning — and how to use them.

The host reads its settings from ~/.config/punktfunk/host.env (a simple KEY=value file, # starts a comment; keys are case-sensitive — punktfunk_compositor sets nothing, use the exact uppercase names). On Windows the service reads %ProgramData%\punktfunk\host.env instead. Your setup guide gives you a starting host.env for your desktop; this page is the full reference for every setting.

You rarely need most of these. The host auto-detects the compositor, input backend, and encoder from your live session — a box that flips between Steam Gaming Mode and a KDE/GNOME desktop is followed automatically. The PUNKTFUNK_* knobs below are mostly optional overrides for forcing a specific backend, tuning performance, or debugging. The starter host.env for your platform sets only the few you actually need.

Session anchors

Leave these unset on a normal setup. Running as a systemctl --user service the host inherits the correct XDG_RUNTIME_DIR from systemd, derives the session bus from it, and rewrites WAYLAND_DISPLAY / XDG_CURRENT_DESKTOP / XDG_RUNTIME_DIR / DBUS_SESSION_BUS_ADDRESS on every connect to follow the active session (Gaming ↔ Desktop) — a value written here can only be redundant or stale.

Setting	When to set it
XDG_RUNTIME_DIR	Only when the host runs outside a user service (ssh, cron): /run/user/<your uid> — check id -u. A copy-pasted 1000 on a box where that isn't your uid points the host at another user's (nonexistent) PipeWire/D-Bus, and everything fails (audio Creation failed, no capture, clients report the host unreachable).
DBUS_SESSION_BUS_ADDRESS	Same cases only: unix:path=/run/user/<your uid>/bus. Otherwise derived automatically.
WAYLAND_DISPLAY	Only the dedicated headless-KDE appliance (wayland-kde, set by its shipped host.env.kde).
XDG_CURRENT_DESKTOP	Same — appliance-only.

Core

Setting	Values	Meaning
PUNKTFUNK_COMPOSITOR	kwin · mutter · gamescope · wlroots · hyprland (aliases: kde/plasma, gnome, sway/wlr)	Which backend creates the virtual display. wlroots is sway/River; hyprland is its own backend. Leave unset. Setting it pins the backend and turns session-following off — per connect and mid-stream, so a Desktop ↔ Gaming switch kills the stream instead of being followed. For CI/tests and dedicated single-session appliances only.
PUNKTFUNK_VIDEO_SOURCE	virtual · portal	virtual creates a per-client display at the client's exact mode (the normal choice). portal captures an existing monitor instead.
PUNKTFUNK_ZEROCOPY	1 · 0 (default on)	GPU zero-copy capture→encode (dmabuf → CUDA → NVENC, or D3D11 on Windows). On by default — no need to set it; it falls back to a CPU path automatically. Set 0 to force the CPU path. One exception: Windows Intel/QSV keeps the CPU path by default until zero-copy is validated on Intel hardware — set 1 to try it there.
PUNKTFUNK_INPUT_BACKEND	libei · gamescope · wlr · uinput	How input is injected. libei for GNOME/KDE, gamescope for Bazzite/gamescope, wlr for Sway/wlroots and Hyprland. Auto-detected with the compositor.
PUNKTFUNK_ENCODER	auto · nvenc · vaapi (Linux) · amf · qsv (Windows) · software	Encoder backend. auto (default) detects the GPU vendor: NVIDIA→NVENC, AMD→VAAPI/AMF, Intel→VAAPI/QSV. software (aliases sw/openh264) is the GPU-less H.264 path on both platforms — on Windows auto falls back to it when no GPU is found; on Linux it is explicit-only (auto never picks it). On a multi-GPU Windows box a forced hardware backend whose vendor contradicts the selected GPU (web-console preference) is overridden — the adapter wins and the host logs a warning; remove the stale pin.
PUNKTFUNK_RENDER_NODE	path	Linux DRM render node for zero-copy (default /dev/dri/renderD128). Set on multi-GPU boxes to pick the right GPU.

Resolution and refresh are not set here — the client chooses them. When a device connects, the host creates a virtual display at that device's resolution and refresh rate. A 1080p60 laptop and a 1440p120 desktop each get their own. (With Moonlight, set the mode in Moonlight; the native clients let you pick a mode or default to the device's display.)

gamescope / session following (Linux, Bazzite/SteamOS)

Two mutually-exclusive models for a Steam/gamescope box. See Steam / gamescope for the full picture (and Bazzite for that distro's specifics).

Setting	Values	Meaning
PUNKTFUNK_GAMESCOPE_ATTACH	1	Attach model: the box owns its gamescope session on its own display (you switch Gaming ↔ Desktop with the Steam UI); the host just captures whatever's live and never tears it down. On a headless box the box-owned autologin session is restarted at the client's resolution on a mismatch; a box driving a physical display, and any foreign/bare gamescope, streams at its own mode.
PUNKTFUNK_GAMESCOPE_MANAGED	1	Managed model (the default where session infra is detected): the host takes the box's gamescope over and relaunches it headless at the client's exact resolution — Game Mode on the virtual screen — restoring the box on idle.
PUNKTFUNK_GAMESCOPE_SESSION	steam	The host owns a gamescope-session-plus (Steam) session at the client's mode (headless appliance; no physical session running).
PUNKTFUNK_GAMESCOPE_NODE	auto · node id	Discover + capture a running gamescope's PipeWire node at a fixed mode. Do not combine with SESSION.
PUNKTFUNK_GAMESCOPE_APP	command	For an ad-hoc bare-gamescope session, the nested command to run (e.g. vkcube).
PUNKTFUNK_SESSION_WATCH	1 · 0	Follow a Gaming ↔ Desktop switch mid-stream (rebuild the backend in place, no reconnect). On by default on Bazzite/SteamOS; set 0 to disable.

Compositor-specific (Linux)

See your desktop page (KDE, GNOME) for when to set these.

Managing virtual displays — keep-alive after disconnect, exclusive vs. extend, and (on Windows/KDE) persistent per-client scaling — now has its own settings surface in the web console and display-settings.json. See Virtual displays. The two *_VIRTUAL_PRIMARY knobs and PUNKTFUNK_MONITOR_LINGER_MS below still work but are superseded by it (a settings file wins over them).

Setting	Values	Meaning
PUNKTFUNK_KWIN_VIRTUAL_PRIMARY	1	Make the streamed per-session output the sole desktop so plasmashell + windows render on it (not on the headless bootstrap output). Set by the KDE appliance host.env. Superseded by the console's Topology setting.
PUNKTFUNK_MUTTER_VIRTUAL_PRIMARY	1	GNOME/Mutter equivalent of the above.

Session recovery (Linux)

Setting	Values	Meaning
PUNKTFUNK_RECOVER_SESSION_CMD	command	Operator hook fired (debounced) when a client connects while no graphical session is live for the host's user — the state a compositor crash leaves behind (gnome-shell SIGSEGV → GDM greeter, whose auto-login is once-per-boot). Typically sudo -n systemctl restart gdm with a matching NOPASSWD sudoers rule, or systemctl restart display-manager under a polkit rule; with auto-login enabled the restart brings the desktop back and the client's automatic retry lands in it. Unset/empty = disabled (the default).
PUNKTFUNK_ON_CONNECT_CMD	command	Fired (detached) when a client connects, on either plane — the event JSON on stdin plus PF_EVENT_* env vars. The zero-config little sibling of hooks.json, which adds filters, webhooks, and debounce.
PUNKTFUNK_ON_DISCONNECT_CMD	command	The client.disconnected counterpart of PUNKTFUNK_ON_CONNECT_CMD (its PF_EVENT_REASON is quit, timeout, or error).

Video quality

Setting	Values	Meaning
PUNKTFUNK_FEC_PCT	N (percent)	Forward-error-correction redundancy for lossy links (the default is sensible for a normal LAN). Higher = more loss-resilient, more bandwidth.
PUNKTFUNK_10BIT	1 · 0 (default on)	HEVC Main10 / HDR. On by default — the host permits 10-bit; a session goes 10-bit only when the client advertises it (behind the client's HDR setting). Set 0 to force 8-bit. Windows host, plus the Linux GNOME 50+ GameStream desktop mirror (PUNKTFUNK_VIDEO_SOURCE=portal, mirrored monitor in HDR mode — check with punktfunk-host hdr-probe). Linux virtual displays (native protocol, GameStream default) stay 8-bit: Mutter's virtual-monitor screencast is SDR-only upstream.
PUNKTFUNK_444	1 · 0 (default on)	Full-chroma HEVC 4:4:4 (Range Extensions) — sharper text/desktop, no chroma loss. On by default on the host; the client's own 4:4:4 setting (default off) is the real switch. Set 0 to force 4:2:0. punktfunk/1 native only (Moonlight stays 4:2:0), HEVC-only, honored only when the client advertises 4:4:4 and the GPU supports it (probed; NVENC is the validated path — VAAPI/AMF/QSV decline). Independent of 10-bit.
PUNKTFUNK_CHACHA20	1 · 0 (default on)	ChaCha20-Poly1305 session encryption for clients without hardware AES (old ARM TVs, e.g. webOS), lifting their ~100 Mbps software-AES decrypt ceiling. On by default on the host; a session uses it only when the client requests it — everyone else stays on AES-GCM. Purely a performance choice (both ciphers are full-strength); set 0 to force AES-GCM for all sessions.
PUNKTFUNK_PYROWAVE_MAX_MBPS	N (Mbps)	Cap the PyroWave Automatic bitrate pin, for a host on a link that the open-loop pin can outrun (e.g. 4:4:4 + HDR at 5120×1440@240 pins ~5.3 Gbps, over a 5GbE link). Unset = no cap. Only affects Automatic (bitrate 0) PyroWave sessions; an explicit client bitrate bypasses it.
PUNKTFUNK_DSCP	1	Opt-in DSCP / SO_PRIORITY QoS tagging on the media sockets. No-op on the wire on Windows without a qWAVE policy.
PUNKTFUNK_OH264_THREADS / PUNKTFUNK_OH264_GOP	N	Software (openh264) encoder tuning: encode threads (default 2 — latency over throughput) and GOP length (default 0 = encoder-auto). Only relevant with PUNKTFUNK_ENCODER=software.

Gamepads

Setting	Values	Meaning
PUNKTFUNK_GAMEPAD	xbox360 · xboxone · dualsense · dualsenseedge · dualshock4 · steamdeck · switchpro · steamcontroller · steamcontroller2 (aliases: ps5, edge, ps4, deck, switch, sc2, ibex, …)	The virtual pad the host creates. Usually auto-resolved from the client's physical controller — set this only to force a type. xbox360 (XInput) is the universal fallback. dualsenseedge gives the client's back paddles native buttons; switchpro gives Nintendo-family pads correct glyphs/layout + gyro. steamcontroller2 (the 2026 Steam Controller) is passed through as-is — the host presents a real SC2 (28DE:1302) that Steam Input drives directly, mirroring the physical pad's raw reports (Linux only). DualSense (Edge)/DualShock 4 work on Linux (UHID) and Windows (UMDF); the Steam Deck pad too (Windows via the promoted UMDF identity); Switch Pro and the classic Steam Controller need Linux UHID. Unsupported choices fold to Xbox 360.
PUNKTFUNK_STEAM_GADGET	1 · 0	Force the raw USB-gadget virtual Steam Deck on/off. On by default on SteamOS, off elsewhere. Lets Steam promote the virtual Deck to full Steam Input.

Audio / microphone

Setting	Values	Meaning
PUNKTFUNK_AUDIO_GAIN	float (default 1.0)	Linear gain applied to capture — bump it for a quiet source.
PUNKTFUNK_MIC_DEVICE	name substring	(Windows) Target mic-uplink device by friendly-name substring (first match wins).
PUNKTFUNK_NO_MIC_INSTALL	set	(Windows) Skip installing the virtual-mic driver (e.g. when the host runs as SYSTEM).

Windows host

Setting	Values	Meaning
PUNKTFUNK_VDISPLAY	pf	Virtual-display backend. The bundled pf-vdisplay IddCx driver is the only backend now — informational; leave as pf.
PUNKTFUNK_SECURE_DDA	1	Capture the secure desktop (UAC / lock / login) so the stream survives those transitions.
PUNKTFUNK_MONITOR_LINGER_MS	ms (default 10000)	Defer tearing a per-client virtual display down after disconnect. A reconnect inside the window preempts it and creates a fresh one (a reused IddCx swap-chain is dead); the stable per-client monitor id keeps Windows' saved display config applying either way. Superseded by the console's Keep alive setting — see Virtual displays.
PUNKTFUNK_EXCLUSIVE_REASSERT_MS	ms (default 2000), 0 = off	How often the host re-checks that exclusive display topology actually held. Windows (or a GPU driver / display-poller tool) can quietly re-activate a physical panel moments after the host disabled it — seen on hybrid Intel+NVIDIA laptops — putting windows, the cursor, and the lock screen on a screen that isn't streamed. The host re-asserts and logs when that happens; 0 restores the old fire-and-forget behavior.
PUNKTFUNK_RENDER_ADAPTER	description substring	Multi-GPU boxes only: force the NVENC/capture GPU by adapter Description substring (e.g. 4090). Leave unset on single-GPU machines.
PUNKTFUNK_HOST_CMD	e.g. serve --gamestream	The host subcommand the service launches. Default serve --gamestream; use serve for a secure native-only host.

Network & discovery

Setting	Values	Meaning
PUNKTFUNK_MDNS	1 · 0 (default on)	mDNS adverts (native + GameStream). 0 skips them (same as --no-mdns) — for networks/containers where multicast doesn't work; add the host by address in the client instead.
PUNKTFUNK_DATA_PORT	port	Pin the per-session video data plane to a fixed UDP port and stream direct (no hole-punch) — open exactly that port in the host firewall. Same as serve --data-port; see Troubleshooting. Default: random port + hole-punch.

Auth, API & paths

Setting	Values	Meaning
PUNKTFUNK_MGMT_TOKEN	token	Bearer token for the management API. If unset it's auto-generated and persisted to ~/.config/punktfunk/mgmt-token (the bundled web console sources it). Set only to pin a specific token.
PUNKTFUNK_UI_PASSWORD	password	Web-console login password. Normally generated on first start and stored in ~/.config/punktfunk/web-password — see Forgot your Password?.
PUNKTFUNK_CONFIG_DIR	path	Override the config directory (default ~/.config/punktfunk) — pairing state, certs, apps.json, captures.

Advanced performance tuning

Leave these at their defaults unless you're chasing latency; see the troubleshooting notes for context.

Setting	Values	Meaning
PUNKTFUNK_GSO	1 · 0	UDP Generic Segmentation Offload on the send path (coalesce a frame's packets into kernel super-buffers) — cuts send CPU ~30%, but its line-rate packet trains can cost delivered throughput on constrained links (measured on a 2.5GbE hop). Off by default until send pacing spaces the super-buffers; set 1 to opt in (auto-falls back to sendmmsg on kernels/paths without support).
PUNKTFUNK_SPLIT_ENCODE	0/disable · 1/auto · 2 · 3	NVENC N-way split-encode for very high pixel rates (5K@240). auto picks automatically above ~1 Gpix/s. H.264 never splits (not applicable per the SDK); on HEVC a forced split disables sub-frame readback (mutually unsupported) — set 0 to choose sub-frame instead.
PUNKTFUNK_NVENC_SUBFRAME	0 · 1	NVENC sub-frame (slice-level) readback for lower latency on sync sessions. Default: on where the GPU supports it (Linux direct NVENC). 0 = never; 1 = force. On HEVC it yields to a forced split-encode (the SDK documents the pair unsupported).
PUNKTFUNK_GPU_PRIORITY_CLASS	off · normal · high · realtime · auto	(Windows) GPU scheduling priority for capture/encode under a GPU-saturating game. Default auto (starts high, upgrades to realtime when it's safe — e.g. HAGS off); high pins the static pre-gate behaviour; realtime is the strongest lever but can freeze NVENC on some setups.
PUNKTFUNK_IDD_DEPTH	N (default 2)	(Windows) IDD-push pipeline depth. 1 cuts latency once GPU priority is raised; higher smooths a contended GPU.

Diagnostics

Setting	Values	Meaning
PUNKTFUNK_PERF	1	Log per-stage timing (capture, encode, send) — handy when tuning latency.
RUST_LOG	info · debug · trace	Log verbosity. On Windows, logs land in %ProgramData%\punktfunk\logs\ (size-capped: a file over 10 MB is rotated to .old at the next service/host start, one generation kept).
PUNKTFUNK_FFMPEG_DEBUG	set	Verbose libavcodec/FFmpeg logging from the encoder.
PUNKTFUNK_VIDEO_DROP	N (percent)	Deliberately drop N% of video packets to exercise FEC recovery. Testing only.

Client-side (native clients)

A few knobs are read by the native clients, not the host:

Setting	Values	Meaning
PUNKTFUNK_DECODER	software · vaapi · vulkan (Linux) · d3d11va (Windows)	Force the decode path. Default auto-selects hardware per vendor (Linux: VAAPI on Intel/AMD, Vulkan Video on NVIDIA and the Steam Deck; Windows: Vulkan Video on NVIDIA/AMD, D3D11VA on Intel and others) with a software fallback.

Bitrate

The client requests a bitrate; the host encodes to it. There's no host-side bitrate knob. To find a good value:

• Native clients (Apple, Linux, Windows, Android): use the built-in speed test (from a host's menu). It measures your link, suggests a bitrate, and applies it.
• Moonlight: set the bitrate in Moonlight's settings. Start moderate and raise it.

Multiple devices at once

The native punktfunk/1 host (serve) streams up to 4 sessions at once by default (an encoder bound); further clients wait in the accept queue until a slot frees up. Each session gets its own virtual display at the client's exact resolution, sharing the host's input/audio/mic services. The limit isn't settable from serve's command line yet — punktfunk1-host, the standalone test host, exposes it as --max-concurrent N (see the Host CLI reference).

Codec and FEC

• Client and host negotiate the codec: HEVC (H.265) by default, AV1 for clients that support it, and H.264 when the session runs on the GPU-less software encoder.
• The native protocol adds forward error correction for lossy links — see PUNKTFUNK_FEC_PCT above.