Behind the pressing plant
Liner Notes
Private Press is built entirely on Apple frameworks — no third-party dependencies, no Electron, no web views. Here's what's inside.
Recorded at
Your audio is never re-encoded.
No ffmpeg. No transcoding. No export pipeline. Private Press reads the binary structure of each format natively — MP4 atoms, ID3v2 frames, FLAC metadata blocks, AIFF chunks — and surgically writes artwork into the metadata layer while your audio data passes through untouched, bit for bit.
Atomic writes
Every press writes to a temporary file first. If anything fails, your original is untouched. The swap only happens after the new file is fully verified.
Format-native editing
Four dedicated editors, each built to understand the binary structure of its format. No generic tag library — hand-written parsers that respect the spec.
FLAC, natively
In-house FLAC encoder and decoder. Pure Swift + Accelerate. RFC 9639 compliant. No libFLAC, no C wrappers. Lossless transcoding between FLAC and ALAC without quality loss.
Full provenance
Every press is logged in an append-only audit trail. You can see exactly what changed, when, and from which source. Nothing happens silently.
Atomic Writes
Temp file → verify → swap.
Original never at risk.
Format-Native Editing
Metadata written. Audio untouched. Bit for bit.
Mastered by
Four engines that know what good looks like.
Artwork passes through a quality pipeline before anything is pressed. All four engines run entirely on your Mac — nothing is uploaded for analysis. The same Apple Silicon that powers your camera pipeline powers Private Press's judgment, entirely offline.
GPU-accelerated analysis
Laplacian edge sharpness and contrast scoring via Apple's Accelerate framework. Runs on the same SIMD units as Metal compute shaders. Catches artwork that's been upscaled from a thumbnail.
Neural Engine classification
A Core ML model on the Neural Engine classifies artwork into quality tiers: genuine high-quality, upscaled, compressed, watermarked, or placeholder. Penalties are applied before you ever see a match.
Perceptual matching
Vision framework feature prints detect duplicate artwork across your collection. Sørensen–Dice similarity scoring with edition token alignment ensures the right art goes to the right album — not just the closest text match.
On-device language models
FoundationModels on macOS Tahoe. Parses and standardizes messy metadata using the Neural Engine — genre normalization, encoding fixes, field extraction. No API, no cloud, no cost.
0–100 Quality Score
Every album scored across artwork, audio, metadata.
Mixed from
Three sources. Best match wins.
Private Press searches three artwork providers simultaneously — iTunes, MusicBrainz, and Discogs. If one goes down, the others keep searching. A performance engine tracks hit rates and confidence per source, learning which providers deliver for your collection and prioritizing them automatically.
Circuit breakers
Each provider runs behind its own circuit breaker. After repeated timeouts or errors, the circuit opens and skips that provider — no wasted time, no cascading failures. It re-closes automatically after a cooldown period.
Confidence scoring
Every match gets a composite confidence score: Sørensen–Dice bigram similarity on names, edition token alignment, track count proximity, and year proximity. Sub-scores are transparent — you can see exactly why Private Press chose a match.
Provider performance
A performance engine computes hit rates, average confidence, and accept rates per provider over time. Providers that consistently deliver high-quality matches for your collection get priority. Your pressing plant learns your taste.
3 Providers, Ranked
Parallel search.
Best confidence wins.
Identified by
Your files know what they are. Even when the tags don't.
When metadata is missing, wrong, or incomplete, Private Press can identify tracks by listening to the audio itself. Two identification engines work in sequence — ShazamKit for catalog matches, then an in-house Chromaprint engine for acoustic fingerprinting — with confidence gating at each stage.
ShazamKit
Apple’s audio recognition framework identifies tracks against a catalog of tens of millions of songs. Returns ISRCs for precise MusicBrainz cross-referencing. No API key required.
Chromaprint engine
A pure Swift acoustic fingerprinting engine built on Accelerate and vDSP. Generates Chromaprint-compatible fingerprints entirely on-device. No C library, no external dependency.
Identification chain
ShazamKit runs first. If confidence is below threshold, the Chromaprint engine generates a fingerprint and queries AcoustID. Results are gated by confidence at each stage — no guessing.
Audio Fingerprinting
ShazamKit + Chromaprint identify unknown tracks.
Produced with
37 Apple frameworks. Nothing borrowed.
Every parser, every editor, every codec, every engine — written in Swift on Apple frameworks. Zero external dependencies. No npm, no CocoaPods, no vendored C libraries, no Sparkle, no Electron. The FLAC codec, audio fingerprinting engine, and auto-update system are all built in-house. The entire supply chain is Apple + us. Private Press ships exactly what Apple ships, which means it gets faster and more capable with every macOS release — and carries zero third-party risk.
Intelligence
Media
Platform
Infrastructure
In-house replacements
UpdateManager — Ed25519-signed auto-updates (replaces Sparkle). FLACCodec — pure Swift + Accelerate, RFC 9639 (replaces libFLAC). ChromaprintEngine — pure Swift audio fingerprinting (replaces Chromaprint C++).
Pressed on
Deep in macOS. Not just running on it.
Private Press isn't a cross-platform app that happens to run on Mac. It reaches into the operating system itself — so your collection is accessible from places no third-party app normally touches.
Spotlight search
Every album in your collection is indexed into CoreSpotlight. Search from anywhere on your Mac and jump straight into Private Press.
Shortcuts, widgets, Menu Bar
Five Siri Shortcuts for hands-free automation. A desktop widget for collection health at a glance. A Menu Bar extra when you want quick status without switching apps.
iCloud state sync
Accepted matches and collection state sync via CloudKit with field-level merge logic. Conflicts resolved intelligently — not by last-write-wins.
Distributed by
Your music doesn't live in one place. Neither does Private Press.
Private Press scans, searches, and presses artwork across your music sources — Apple Music and local folders. Point it at your library or any directory and it handles the rest. One app, one workflow, regardless of where your files live.
Apple Music
Scans your full Apple Music library via the iTunesLibrary framework. Artwork quality is analyzed without touching your files — when you press, format-native binary editors write directly into M4A, MP3, FLAC, or AIFF with atomic backup.
Folders & NAS
Point Private Press at any directory — local disk, external drive, or NAS volume. It walks the tree, reads metadata from every file using binary parsers (no AVFoundation), and remembers the location across launches via security-scoped bookmarks.
Pressed to Coming to Pro
Your other Mac gets it too.
Press Sync is a peer-to-peer sync engine built on Apple's Network framework. Your Macs discover each other via Bonjour on your local network, authenticate via iCloud identity or a one-time PIN, and transfer pressed artwork directly — no cloud relay, no server. A custom binary protocol with 12 message types handles the entire session from handshake to verified completion.
Zero-config discovery
Bonjour finds your Macs automatically. Authenticate with your iCloud identity or a one-time PIN. No server, no account, no port forwarding.
Verified transfer
Files transfer in 1MB chunks, each independently verified with SHA-256 via CryptoKit. Transfers are resumable — close your laptop, pick up where you left off.
Quality arbitration
Press Sync doesn't just copy files. It scores audio quality and artwork quality on both sides, keeps the best audio, transplants the best artwork, and gives you one collection that's better than either Mac had alone.
Built with Swift 6 strict concurrency. Pure native code.
No Electron. No web views.
No corners cut.