Support

DSF (DSD64/128/256) bit-exact to DoP-capable USB DACs; FLAC, ALAC, WAV, AIFF at native rate; MP3, AAC for legacy files.

DSD is a 1-bit format iOS doesn't decode natively. The app packs DSD into DoP frames and sends them to a USB DAC, which unpacks and plays the original bits. Without a DoP-capable DAC, DSD files show a DSD rate not negotiated error.

Any USB DAC that advertises DoP (DSD-over-PCM) support. Connect via USB-C (newer iPhones) or a Lightning-to-USB camera adapter. If your DAC's documentation mentions DoP, it will work.

By default, the entire DSF file is downloaded before playback begins. This guarantees DoP marker alignment never hiccups mid-track. For large DSD256 files this can take 10–30 seconds on first play. Enable Settings → Stream large DSD files to trade that for faster starts — works well on stable Wi-Fi, less so on flaky networks.

If your library is large and the first scan didn't finish in the foreground, 1-bit schedules a one-shot background task with iOS to pick up where it left off — only when your phone is charging, idle, and on Wi-Fi. iOS decides when (and whether) to run it; there's no network traffic beyond the same SMB or bridge connection you'd already authorised. Turn it off in Settings → Refresh → Opportunistic background scan if you'd rather it didn't.

DSD is intentionally hidden from CarPlay. DoP markers can't survive head-unit playback — the head unit doesn't pass them straight through to a USB DAC, so the only way to play DSD on CarPlay would be to silently transcode it, which 1-bit refuses to do. Your DSD library is still there on the phone; switch to the iPhone screen for DSD playback.

App-private Application Support. They're hidden from the Files app, excluded from iCloud backup so they don't eat your iCloud quota, and removed when you delete the download, delete the share, or uninstall 1-bit. They never leave your device.

No tracking, no analytics, no account system. Outbound traffic goes to servers you control — your SMB shares and your own bridge. The only third-party request is the optional Deezer artist-image lookup (anonymous, off unless you turn it on). New in v1.5: playlist backup and listening history are both off by default and, when enabled, go only to the bridge you run — never to me or anyone else; DLNA playback stays on your LAN. New in v1.7: an optional Atlas metadata service (off by default, turned on per bridge) can fetch richer artwork and artist notes — it sends only the MusicBrainz ID of the item you're viewing and keeps a minimal anti-abuse record that isn't linked to you and is never used for tracking; because it can be switched on, the App Store privacy label now lists an Identifiers item used only for app functionality and fraud prevention. Siri, also new in v1.7, is handled on Apple's side — the app only receives the resolved "play this" request. Credentials and bridge tokens live in the iOS Keychain on-device. The full privacy policy has the line-by-line breakdown.

No. This app is for playing files you own, from a server you control.

Yes. v1.5 can cast a bridge track to a DLNA / UPnP renderer on your network — a Chord 2Go is the headline target, and generic renderers (mconnect, BubbleUPnP, Linn Kazoo) work too. For a bridge source, enable the bridge's DLNA MediaServer (off by default), then pick the renderer from the Now Playing output picker; the renderer streams the audio directly from your bridge, bit-exact, over your LAN. As of v1.6 you can also cast a track from a UPnP/DLNA media server source — the renderer fetches straight from that server (2Go → 2Go works). SMB and on-device tracks can't be cast this way — there's no URL for the renderer to fetch from. Because DLNA has no authentication, only turn the bridge's MediaServer on for networks you trust.

Either works. SMB is fine if your server already speaks it well and you only listen on the same Wi-Fi as the server. The bridge is faster (a pre-indexed manifest replaces the SMB walk + tag-enrich pass), much easier to reach from outside your home network (over Tailscale, WireGuard, or any direct connection), and side-steps the Samba edge cases that cause most "Couldn't connect" reports. See the bridge page for the full picture.

TLS fingerprint pinning. The iOS app captures the bridge's certificate SHA-256 on first contact (during pairing) and pins it forever after. No public CA, no browser trust store, no MITM window after pairing. If the bridge's certificate ever rotates, the app refuses to connect and prompts you to re-pair from the admin console — this is by design, not a bug.

iOS 26.4 enforces the Apple ATS 398-day cert-validity cap at the network layer, so the bridge's self-signed certificate must be re-issued at most once a year. The bridge handles this automatically (it warns in the admin console at ≤30 days), but you'll need to re-scan the QR code or open a fresh bridge:// deep link from the admin console when the cert rotates. The pin guarantees this is intentional — re-pairing is the only way to authorise a new certificate, and that's what keeps the connection MITM-resistant.

Yes — Tailscale or WireGuard both work. The bridge speaks plain HTTP/2 over TLS; anything that gets a TCP connection to it can pair. Tailscale is the easiest: install it on the bridge box and your iPhone, and the bridge is reachable on its tailnet address from anywhere. See the Tailscale troubleshooting note below if you're using bare CGNAT IPs (the iOS-specific gotcha is documented there).

• Server online and on the same Wi-Fi as your iPhone
• Hostname/IP correct — try pinging from a Mac on the same LAN
• SMB2 (or higher) enabled on the server — SMB1 is not supported
• Share name matches exactly (case-sensitive on most servers)

• Username is typically without domain prefix (ars, not WORKGROUP\ars)
• Some NAS systems require enabling "SMB file sharing" separately
• Test the same credentials from Finder → Go → Connect to Server to isolate client vs. server issues

• USB DAC connected and powered on before starting playback
• DAC's DoP indicator showing DoP (not PCM)
• Some DACs need a powered hub for higher DSD rates via Lightning adapters
• Toggle Settings → Stream large DSD files off to force full pre-cache

Your DAC doesn't advertise DoP for that sample rate. Confirm DoP mode is enabled on the DAC, and try a DSD64 file before DSD128/256.

• A share-level connection drop aborts a scan. Tap Scan again — it skips folders that already completed.
• If a specific folder fails consistently, the Shares tab shows the underlying error.

Use Full rescan from the menu. Incremental scans skip folders whose modification time hasn't changed, so server-side renames need a full pass.

Bridge-side issues — pairing failures, "TLS fingerprint doesn't match", "certificate has changed since pairing", Tailscale CGNAT problems, protocol version mismatches, slow enrichment — are covered with full step-by-step fixes on the bridge troubleshooting page:

The short version, for the most common case (annual cert rotation): the bridge's TLS certificate is renewed at most once a year (Apple ATS caps self-signed cert validity at 398 days). When that happens, the iOS app refuses to silently accept the new cert by design. Open the bridge admin console, regenerate the pairing, and re-scan the QR or open the fresh bridge:// link on iPhone.