MP5 Audio

An experimental open-source audio format, container, codec, converter, and player project.

Version: MP5 Audio v0.28.0-beta (Public Beta)
Live demo: https://mp5-audio.vercel.app
GitHub: https://github.com/cjocollin/MP5-audio

MP5 Public Beta uses MP5-L v4 as the recommended lossless mode. MP5-C and MP5-H are experimental research modes. MP5 does not claim to beat MP3, AAC, Opus, or FLAC. No DRM. Rights metadata is informational only. No telemetry, upload, or cloud sync is added by the reference app.

Report bugs: GitHub Issues or in the hosted app: Settings -> Report a bug / Give feedback. Paste Settings -> Diagnostics -> Copy diagnostics if useful; no files are uploaded automatically.

What Is MP5?

MP5 (.mp5) is an experimental smart audio container for browser-based music, podcast, library, and app workflows. It stores audio plus optional context: metadata, cover art, lyrics, waveform/seek data, content guidance, mood/vibe tags, stems, visual themes, integrity metadata, and album packages.

Single-track .mp5 remains the core format. Album packages use .mp5p in either manifest mode (JSON plus sidecar .mp5 files) or embedded mode (one self-contained binary package).

Current Status

Area	Status
Overall	Public Beta / experimental; not production-ready for archival or legal use
MP5-L v4	Recommended lossless path; bit-exact roundtrip (v3 lab/legacy)
MP5-C	Lab-only; quiet-passage hiss is measured (see codec status)
MP5-C vNext (MP5C2)	Lab/advanced gated export (CodecId 5, AUDI 0x43 0x34); protect 1.5; prefer High preset; not default
MP5-H	Experimental hybrid; large (avg >1× PCM); not default
PCM	Reference/debug fallback
.mp5p	Experimental album package; browser memory limits apply
Public claims	No beat-codec, DRM, legal-proof, telemetry, upload, or cloud-sync claims

v0.28.0-beta Focus

Lab MDCT loud path (mp5c3, vNext TAG_MDCT) with FFT Type-IV for practical WASM, plus real-track MDCT validate (High ~0.214× / Extreme ~0.268× PCM, hiss risk low at protect 1.5). Default encode_mp5c_vnext still uses legacy MP5-C for loud units; MDCT is opt-in lab only. Gated CodecId.MP5C2, protect 1.5, and MP5-L default/batch are unchanged. No mainstream-codec claims. See MP5C_VNEXT_RESULTS.md.

pnpm audio:hiss-report                       # hiss matrix + Hiss Risk + protected % (git-ignored)
pnpm audio:validate-vnext-ref                # real-track protect-scale gate (needs lab.config)
pnpm audio:export-listening:vnext            # PCM + MP5-L + MP5-C + vNext (smooth/native/...) WAVs
cargo test -p mp5-codec --release            # native codec tests (incl. mp5c2 + MP5-C-unchanged)

Developer Toolkit

• Developer quickstart
• Compatibility matrix
• Fixture catalog
• Chunk registry
• Format spec
• Container spec
• Metadata spec
• Audio quality lab
• Codec status
• MP5-C hiss audit
• MP5-C vNext plan
• MP5-C vNext results
• Known issues

CLI tools:

pnpm inspect:mp5 <file.mp5|file.mp5p>
pnpm validate:mp5 <file.mp5> --profile playable
pnpm validate:mp5p <file.mp5p> --profile package

Profiles: basic, playable, rich, strict, package.

Quick Start

pnpm install
pnpm wasm:build
pnpm demo

Local demo: http://localhost:5173

Contributor gates:

pnpm lint
pnpm test
pnpm test:compat
CI=1 pnpm test:e2e
pnpm playback:check
CI=1 pnpm beta:check
CI=1 pnpm beta:check
pnpm build
pnpm deploy:check

Audio quality lab (synthetic fixtures; no copyrighted audio, no telemetry):

pnpm audio:gates            # codec quality gates (also part of pnpm test)
pnpm audio:bench            # full bench → benchmarks/audio-quality/ (git-ignored output)
pnpm audio:quality-report

See CONTRIBUTING.md for full setup, fixture rules, and PR expectations.

Hosted Demo Paths

• Open https://mp5-audio.vercel.app
• Try Load MP5-L demo and play the synthetic tone.
• Open Demo guide and try the karaoke and embedded album demos.
• Open Converter and Batch tabs.
• Check Settings -> Diagnostics for copyable, path-redacted diagnostics.

The hosted demo uses synthetic fixtures only. Do not commit or deploy copyrighted/private local audio.

Screenshots

Player	Converter	Metadata

More captures: docs/screenshots/

Supported Workflows

• Player: open .mp5, manifest .mp5p, or embedded .mp5p; queue, play, seek, inspect format, view lyrics/karaoke/stems/VISU when present.
• Converter: drop WAV/FLAC/MP3/M4A/OGG sources; export MP5-L v4; edit metadata manually.
• Batch: convert multiple local files to MP5-L v4; package as manifest or embedded .mp5p; validate package output.
• Library: optional browser-local IndexedDB/localStorage save for tracks and packages on this device only.

Safety And Privacy

MP5 parses binary container and audio data in the browser and CLI tools. Treat untrusted .mp5 and .mp5p files as experimental inputs, not as hardened production media.

• All conversion and package building in the reference app is local to the browser tab.
• No telemetry, upload, cloud sync, DRM enforcement, or rights/legal verification.
• Local library data is stored by the browser on this device only.
• Keep original source files backed up.
• Report security issues privately via SECURITY.md.

Important Limitations

• Experimental Public Beta; not production-ready for archival/legal use.
• Large WASM/FFmpeg downloads on first visit.
• Browser encode/decode can be CPU- and memory-intensive.
• MP5-C may hiss; MP5-H files can be large.
• Large albums and stems can stress mobile devices.
• MP5 does not claim to beat MP3, AAC, Opus, or FLAC.

Project Layout

Path	Purpose
apps/web/	Player, converter, library, demo, settings
packages/mp5-container/	.mp5 / .mp5p parser, writer, compatibility reports
rust/mp5-codec/	MP5-L / MP5-C / MP5-H codec work
tools/audio-lab/	Audio quality lab: fixtures, metrics, null test, listening export
benchmarks/audio-quality/	Generated lab reports (git-ignored output)
test-fixtures/	Synthetic demo and compatibility fixtures
docs/	Specs, toolkit docs, deployment notes, release readiness

License

MIT - experimental research prototype. Copyright (c) 2026 Collin O'Keefe.