Name: 1-bit
Author: Ars

Why 1-bit?

DSD stores audio as a single bit per sample at 2.8, 5.6, or 11.2 MHz — the DAC reconstructs the waveform from density. iOS has no first-party way to play DSD. Most apps transcode it to 48 kHz PCM and move on. 1-bit doesn't.

What's new in 1.3

Opportunistic background scan Your first scan of a big library can keep going after you background the app, when the device is charging and idle. iOS schedules it, the work stays on your phone, and the off-switch is in Settings → Refresh.

Classical metadata Composer, conductor, and work fields land in the library so opera, symphonic, and concert recordings group the way the music does — not flattened against ALBUMARTIST.

Listening tips, in one place A new in-app guide collects the things that make 1-bit sound the way it should: DAC selection, DoP, gapless, why DSD pre-caches by default, when to bypass crossfeed.

Long-press a folder Hold any folder in the browser to play it, queue it next, append to a playlist, or jump to its album — without leaving the browse view.

Refined cellular streaming Wi-Fi only and Warn before streaming now also stop the next-track preloader from quietly reaching for cellular. Low Power Mode is honoured the same way.

Same audio path No transcoding. No resampling. No hidden processing. The app — and the bridge — move bytes; the DAC does the rest.

What it does

Plays from three sources — an SMB share, a 1-bit bridge you run yourself, or files on the iPhone itself
Scans into a proper library — albums, artists, playlists, artwork
DSD (DSF) bit-exact to a USB DAC via DoP — DSD64, DSD128, DSD256
PCM (FLAC, ALAC, WAV, AIFF, MP3, AAC) at the file's native sample rate
Gapless between tracks when the format matches
Now Playing, Lock Screen, AirPods, CarPlay, Apple Watch controls

How DSD playback is handled

Bit-exact, end to end

DSF files are read off your network or local storage, wrapped in DoP (DSD-over-PCM) frames, and handed straight to the USB audio endpoint. There is no system mixer in the path, no resampling, no dithering, no hidden processing. If your DAC reports DoP lock, you are hearing the original 1-bit stream.

DSD playback uses a full file pre-cache by default, so the DoP marker stream cannot stutter mid-song under network jitter. An opt-in "Stream large DSD files" Settings toggle trades that for faster starts on a reliable link. PCM goes direct: the hardware sample rate is renegotiated to match the file — 44.1, 88.2, 96, 176.4, 192 kHz, whatever is on disk.

The render thread is lock-free: no syscalls during the audio callback, atomic publication of state across threads, and per-DAC PLL settling tuned for the trickier hardware (Chord FPGAs need longer than most). DoP marker phase is preserved across track boundaries so gapless DSD doesn't flicker between songs.

Going through a 1-bit bridge? TLS fingerprint pinning means only the bridge you paired with — captured on first contact — can serve audio to your phone. No public CA, no MITM window, no transcoding on the wire.

Three sources, one library

SMB share Point the app at your NAS or Mac File Sharing, scan, listen. Credentials live in the iOS Keychain.

1-bit bridge ↗ Free, open-source companion server. Faster than SMB, reachable over Tailscale or WireGuard, side-steps the Samba edge cases.

On-device library Drop files into the app's Documents folder via Files or Finder over USB. No server needed.

Requirements

iOS 18.6 or later, iPhone or iPad
At least one of: an SMB share (Synology, QNAP, TrueNAS, macOS File Sharing, Samba), a 1-bit bridge on Mac / Windows / Linux / Raspberry Pi, or files in the app's Documents folder
For DSD: a USB DAC with DoP support (USB-C or a Lightning-to-USB camera adapter). PCM plays through any output, including Bluetooth and the built-in speaker.

Privacy at a glance

No account, no sign-up, no analytics, no ads, no tracking.
SMB credentials and bridge bearer tokens stay in the iOS Keychain on your device.
Zero personal data collected — inherently complies with the GDPR, the Swiss FADP, and the CCPA.
Full privacy policy →

1-bit