Windows audio substrate: minted Punktfunk endpoints retire VB-Cable #98
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Reference: unom/punktfunk#98
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The host now mints its own audio endpoints from Steam's streaming drivers — "Punktfunk Speakers" (the client-only desktop-audio sink) and "Punktfunk Microphone" (mic passthrough) — and wires them by identity as the plan's tier-0. VB-Cable is fully de-bundled: audio needs Steam installed (never running); a user-installed cable keeps working as a fallback mic target. Field-verified end to end on the RTX box, including the mic at true pitch.
Design + full measurement record:
punktfunk-planning/design/windows-audio-endpoints-and-vbcable.md.What's in here
Wiring correctness (ships value even without minting)
windows/install.rs(landed while the Windows CI runner was down).The minted substrate
audio/windows/minted.rs: devnode-per-role provider (marker-matched across restarts, startup worker + cooled-down retry, default-grab restoration), built on a shared minting surface extracted frompad_endpoint.rs(create_media_devnode,bind_driver,write_stamps, capture-side endpoint lookup with the correct{0.0.1.…}id prefix).wiring_plan:MintedIdstier-0 by recorded endpoint ID (names cannot distinguish minted instances from Steam's primaries — measured), capture side paired by ID, minted sink heads the silent tier with the same narrowing discipline,AudioReadinessclassification logged with every plan.VB-Cable retirement
Surfacing
/statusgainsaudio(readiness, role endpoint names,mic_withheld/last_resort/narrowing); openapi regenerated, drift test green.punktfunk-host audio-probedevtest: the S1–S3 spikes plusmint,plan,micpitch(zero-crossing pitch detector — peaks are pitch-blind, which is how the octave bug initially slipped through) andmicpins(exclusive/shared format-capability map).Measurements behind the decisions
micpitch440 Hz → 220 Hz before the format stamps; 440 Hz → 440 Hz at exact peak after. Both pins accept stereo/48 kHz (micpins).nvenc,amf-qsv,qsv),audio::tests 81/81, openapi drift.Still open (follow-ups, not blockers)
The S1-S3 spikes from windows-audio-endpoints-and-vbcable.md as one runnable devtest (no game, no client, ssh-drivable): audio-probe ssm S3, the decision gate: mint a SECOND devnode of Valve's Steam Streaming Microphone driver and prove the pair end to end (tone into its render endpoint must come back out of its capture endpoint). Pass = a punktfunk-owned virtual mic needs no VB-Cable wherever Steam is installed. audio-probe sink S2: mint a Speakers instance, park the DEFAULT playback on it, tone through the default device, WASAPI-loopback the instance - the desktop-audio capture path minus the game. audio-probe sss-primary S1: the primary Speakers' known-silent loopback, re-measured, with mix format + steam.exe state. audio-probe cleanup remove every probe-minted devnode (marker value in Device Parameters, never name-guessing). pad_endpoint grows the first slice of the design's §C1 shared minting surface: create_media_devnode(desc, hwid, mark), bind_driver(hwid, inf), find_capture_endpoint_for_devnode — the pad provisioner now calls the same functions. The probe restores whatever default devices the minting disturbed before it exits.The audio-substrate program's Phase 2 (spikes S2+S3 measured green on the target box): the host mints its OWN instances of Valve's streaming-audio drivers and wires by IDENTITY instead of borrowing Steam's primaries — minted.rs the provider: one devnode per role ('Punktfunk Speakers' from SteamStreamingSpeakers.inf, 'Punktfunk Microphone' from SteamStreamingMicrophone.inf), marker-matched across restarts (PunktfunkAudioRole in Device Parameters — names are NOT identity, a minted instance is name-identical to the primaries), provisioned on a startup worker like pad audio, retried with a 60 s cool-down from wiring passes, defaults restored when a fresh endpoint grabs them. wiring_plan MintedIds tier-0: the mic takes its minted device outright (capture side paired by the provider's id — a name search cannot tell it from the primary), the loopback prefers the minted sink at the head of the silent tier, an operator override still beats everything, a narrowing minted sink demotes below real hardware, and stale ids fall back to the ladder unchanged. Plus AudioReadiness — the full/audio-only/mic-only/nothing classification, logged with every plan change (§C4's seed). audio-probe 'mint' runs the provider synchronously; 'plan' prints one real wiring pass + readiness — the field-triage command. Without Steam's drivers nothing changes: provisioning degrades to absent ids and the plan keeps the name-based ladder (primaries → cable → real hardware) exactly as before.The other half of the audio-substrate decision (spikes S2+S3 green, minted endpoints landed in the previous commit): stop bundling a third-party kernel driver the host no longer needs. installer the VB-CABLE task, payload, silent-install run and the donationware notice are gone; a suppressible notice tells a Steam-less box that audio needs Steam INSTALLED (never running) and that installing it later just works. A cable from an older install is still deliberately not removed. packer + CI -VbCableDir/VBCABLE_DIR, the staged-payload check and the runner provisioning download are gone; SBOM drops the redistributed-driver component. winget the VB-Audio bundling-grant agreement becomes the honest Steam requirement (surfaced on the unattended path where no wizard is on screen). docs windows-host/uninstall/security/echo say what actually ships: no kernel-mode driver of our own, endpoints minted from Valve's vendor-signed drivers, VB-CABLE mentioned only as the historical fallback that keeps working. host wording the mic-open guidance and module headers lead with Steam; the NAME ladder itself is untouched — demoting 'cable input' was considered and rejected (on a box where minting transiently fails, the SSM would outrank an installed cable, steal the silent sink, and make audio host-audible).The capture-direction lookup built its endpoint id with the RENDER prefix {0.0.0.00000000}., but WASAPI's enumeration returns capture ids as {0.0.1.00000000}.{guid} — so the minted microphone's capture side never string-matched the enumeration and the wiring plan paired no recording device (audio-probe plan on the target box: mic_capture = '-'). Measured; IMMDeviceEnumerator::GetDevice tolerated the wrong prefix, which is why the S3 spike's direct open still passed.Exclusive+shared IsFormatSupported across {1,2}ch x {16,32}bit x {44.1,48,96}kHz on both minted mic pins. Interrogates the DRIVER, bypassing every endpoint-store stamping question: what the pins truly accept decides whether the mic leg has any coherent configuration, and whether an exclusive-mode mono open is an escape hatch. (The pad program made its own breakthrough with exactly this instrument on the sibling SSS driver.)