Beat Saber on Apple Silicon → Quest 3

Run the Windows build of Beat Saber 1.29.4 on an Apple Silicon Mac under CrossOver and stream it to a Meta Quest 3 over WiFi with the stock ALVR client — full 6DoF tracking, 72 fps, 102.9 ms p50 / 130.5 ms p95 motion-to-photon on-head over WiFi (native arm64 HEVC helper).

Measured status (2026-08-04, 3008x1664@72, 80 Mbps, evidence/batchA-soak-20260804-results.md): WiFi desk-idle 106.9 ms p50 / 130.7 p95 over 231k frames; 60-minute soak with zero uninduced encoder-helper deaths; ~5-6 dropped frames/s at the 80 Mbps cap (bitrate tuning open). USB-wired measured 93.5 ms p50 — a transport-isolation figure from the helper validation gate, not the WiFi product number.

Beat Saber (Windows, x64) ─ CrossOver/Wine ─ DXMT (D3D11→Metal, zero-copy)
        └─ wineopenxr ─→ oxrsys OpenXR runtime (x86_64, compose in-process)
              └─ IOSurfaces via Mach send rights (once per generation)
                    └─ arm64 helper: VideoToolbox HW HEVC encode
                          └─ Annex-B over socketpair ─→ embedded ALVR core (x86_64) ─ WiFi/USB ─→ Quest 3

Everything runs in-process on the Mac; no SteamVR, no real Steam at runtime. See docs/architecture.md for how the pieces fit.

Requirements

• Apple Silicon Mac (verified: M3 Max, macOS 26.x) with ~15 GB free disk

• CrossOver 26.2+ installed in ~/Applications or /Applications, with a win11_64 bottle — its name is required by every command below (examples use Steam; create one in the CrossOver UI first)

• A Steam account that owns Beat Saber (game files only; Steam never runs)

• Meta Quest 3 with the ALVR client v20.14.1 on the same 5/6 GHz WiFi as the Mac (install in step 4 below)

• Toolchain — requires Homebrew; git/python3/clang come with the Xcode Command Line Tools (xcode-select --install):

  brew install cmake ninja mingw-w64 android-platform-tools
  brew install switchaudio-osx blackhole-2ch   # optional: in-headset audio (reboot after)
  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh   # rustup (brew's is keg-only/not on PATH)
  source "$HOME/.cargo/env"                                        # put rustup on PATH in THIS shell
  rustup toolchain install stable && rustup target add x86_64-apple-darwin

One-time setup

1. Clone (submodules are fetched by setup):

git clone https://github.com/dingyifei/wine-vr.git && cd wine-vr

2. Get Beat Saber 1.29.4 — the last build before the Meta account gate and the first with native OpenXR. Download the pinned depot with DepotDownloader and your Steam login:

DepotDownloader -app 620980 -depot 620981 -manifest 6291266771922375922 \
  -username <steam-user> -dir "<beat-saber-dir>"

(DepotDownloader has no brew formula: grab the macos-arm64 release zip, chmod +x DepotDownloader && xattr -d com.apple.quarantine DepotDownloader, run as ./DepotDownloader.)

Any <beat-saber-dir> works — pass it as --bs-dir below (default: <bottle>/drive_c/Program Files (x86)/Steam/steamapps/common/Beat Saber 1294; a directory outside the bottle is reached through the bottle's z: drive, which CrossOver creates by default — doctor checks it). Alternative: Steam console (steam://open/console) → download_depot 620980 620981 6291266771922375922, then move the output there.

3. Fetch, build, install:

./demo.sh setup                      # submodules + sha256-pinned binaries + config
./demo.sh build                      # oxrsys (x86_64 + ALVR core) and wineopenxr
./demo.sh install --bottle Steam     # bridge into CrossOver + bottle (one sudo prompt)

setup writes the runtime config to ~/Library/Application Support/OXRSys/oxrsys-runtime.toml with protocol = "alvr" and bitrate_mbps = 42 (it never overwrites an existing file). The embedded ALVR core keeps its session.json under ~/Library/Application Support/OXRSys/alvr/ — note this is not stock ALVR's config directory; it is auto-created on first run and LAN clients are auto-trusted, so no pairing dance is needed.

4. Quest client: install ALVR v20.14.1 on the headset — grab alvr_client_android.apk from the ALVR v20.14.1 release and adb install it (or use SideQuest). Sideloading needs Developer Mode: enable it in the Meta Horizon phone app (free developer account required) and accept the USB-debugging prompt in the headset. The client version must match the embedded server core; a newer store/app-lab client may refuse to pair.

Run it

./demo.sh run --bottle Steam [--bs-dir "<beat-saber-dir>"]

Put the headset on and open the ALVR client; the first frame can take ~30 s. Pause = X/A button or the Quest system button. (The left menu button not pausing is a Beat Saber/Unity limitation on every OpenXR runtime since the 1.29.4 OpenXR port — see docs/history/menu-button.md.)

run is the repeatable stage: it resets the bottle's wineserver (stale servers hang startup), preflights everything with actionable errors, applies the Goldberg Steam emulator to the game, routes audio into BlackHole, and launches through the bridge. Logs land in logs/.

To exit: quit from the game menu, or Ctrl-C (tears down wine and restores audio), or ./demo.sh stop --bottle Steam from another shell. Note that audio routing sends all Mac output to the headset while the game runs — pass --no-audio to keep sound on the Mac. The console stays quiet by default; --verbose enables the wine/openxr debug channels.

Checking your setup

./demo.sh doctor --bottle Steam

~30 ordered checks, each failure with a one-line remedy — including the cases that silently break later: a CrossOver update reverting the DXMT overlay, a stale bottle, or a leftover client IP pin in session.json.

Configuration

Knob	Where	Meaning
--bottle / WINEVR_BOTTLE	CLI/env	CrossOver bottle name (required)
--bs-dir / WINEVR_BS_DIR	CLI/env	Beat Saber 1.29.4 install dir
--no-audio / WINEVR_NO_AUDIO	CLI/env	keep sound on the Mac (skip BlackHole routing)
--no-dashboard / WINEVR_NO_DASHBOARD	CLI/env	don't open the ALVR server dashboard with run
--verbose / WINEVR_VERBOSE	CLI/env	wine/openxr debug channels in console + log
--wired / WINEVR_WIRED	CLI/env	create the adb forward tcp:9943/9944 pair for USB-wired streaming (a normal run clears them)
protocol = "alvr"	oxrsys-runtime.toml	streaming backend (demo path)
bitrate_mbps	oxrsys-runtime.toml	base video bitrate (template writes 42; sessions to date ran at 80, which sheds ~5-6 frames/s at the cap — tuning open; ALVR's adaptive loop adjusts from the base)
encoder_process = "auto"	oxrsys-runtime.toml	auto/native = out-of-process arm64 helper (HW HEVC), hard-required at launch — run's preflight restages a missing/wrong-arch helper from the build tree, or fails with a remedy; inproc = in-process Rosetta H.264 fallback
video_codec = "auto"	oxrsys-runtime.toml	h265/h264/auto — honored for real on the helper path; the inproc fallback under Rosetta is H.264-only
resolution_scale, refresh_rate_hz	oxrsys-runtime.toml	encode-side downscale (1.0 = native) and refresh rate (72 verified)

The runtime's toml parser strips same-line # comments (outside quotes). Runtime builds before the 2026-08 fix silently mis-parsed keys carrying a trailing comment — if you run an older dylib, keep comments on their own lines.

Known limitations

• H.264 only under the in-process fallback (encoder_process = "inproc") — the runtime encodes under Rosetta, where VideoToolbox HEVC paths misbehave (one bug is documented and filed: see docs/apple-feedback-1-lowlatency-bgra-zero-chroma.md). The default out-of-process arm64 helper (auto/native) encodes native HW HEVC and negotiates codec choice with the client for real.
• Left menu button cannot pause (game limitation, all OpenXR runtimes)
• Verified config is a Debug x86_64 build; other configs are untested

Repo map

Path	What
demo.sh, scripts/demo/	the demo pipeline (this page)
ext/oxrsys	submodule: OpenXR runtime + embedded ALVR backend (fork)
ext/wineopenxr	submodule: Wine OpenXR bridge (fork)
ext/ALVR	submodule: ALVR v20.14.1 + reliability patches (branch)
patches/	the ALVR patch set as a reviewable diff (patches/README.md)
docs/	architecture · troubleshooting · bridge findings · history
tools/, scripts/dev/, src/	investigation-era probes and reproducers

Further reading: docs/bridge-findings.md (what was built and why, gate by gate) and docs/history/steamvr-blocked.md (why the obvious SteamVR-under-Wine path is impossible today).