malstrom

A maelstrom of .als files, tamed. Scan a folder of Ableton Live Sets, see what musical scale every project and clip is compatible with, and filter your whole library by key.

Point it at a folder of .als files and it will:

• Scan the directory (top-level only, not subfolders) and list every project in a filterable, virtualized table.
• Read each project's explicit ScaleInformation key/scale tags where present.
• Infer compatible scales directly from MIDI clip note content when a project has no explicit scale set.
• Filter the whole list by scale, so you can answer "which of my projects are in D Dorian?" in one click.
• Apply a chosen scale back to a project, tagging every MIDI clip that's compatible with it.

This is early — v0.1, unreleased. What's solid vs. what's still missing:

Works today

• Directory scanning + virtualized/filterable project table
• Explicit ScaleInformation parsing
• Scale inference from MIDI clip content
• Filter-by-scale UI
• Applying a scale to a project, writing it onto every compatible MIDI clip

Not yet

• No packaged release — run from source (below)
• Near-matches (a clip one or two notes off from a scale) aren't detected; only exact pitch-class matches count

Working on the backend, not yet in the UI. Checked by opening the output in Ableton Live, but only on a small sample of files from the current Live version. Projects saved in older Live versions haven't been tested.

• Mashup (src-tauri/src/als/mashup.rs): splice selected tracks from two .als projects into one new, valid Live Set. Exposed as the mashup_create Tauri command.

• Dev CLIs (src-tauri/src/bin/) that drive the real Live app via macOS accessibility (osascript) to prove its output loads:

  • mashup_batch_test <dir> [report.jsonl] — mash up every pair of projects in a folder, open each result in Live, and log pass/fail to a resumable JSONL report
  • als_upgrade <file-or-dir> — have Live re-save older-version sets as current-schema copies (unverified; expect rough edges)

  Run with cargo run --bin <name> -- <args> from src-tauri/. They open and force-quit Live, so don't run them with unsaved work open.

• .als files are gzipped XML; the Rust backend decompresses (flate2) and parses (roxmltree) them, and writes changes back with a backup of the original first.
• Scale inference reduces every MIDI clip to its pitch-class set and scores it against all scale/root combinations.
• Scanning runs off the UI thread in parallel (rayon) so the app never freezes on large libraries.
• The table is virtualized (@tanstack/react-virtual) to stay smooth with thousands of rows.
• Tests at three layers: Rust integration tests, Vitest unit tests, Playwright end-to-end tests.
• Built with Claude Code; .claude/skills/ holds the project-specific agent skills used during development.

Developed and tested on macOS only. Windows/Linux aren't supported — PRs welcome if you want to make it work there.

• Rust toolchain (stable)
• Node.js and pnpm
• Xcode Command Line Tools — see the Tauri macOS prerequisites

pnpm install
pnpm tauri dev

pnpm tauri build

cargo test       # from src-tauri/ — Rust unit tests
pnpm test        # vitest — frontend unit tests
pnpm test:e2e    # playwright — end-to-end UI tests

The .als parsing and scale-scoring logic lives in src-tauri/src/als/ — see its README for how scale information is extracted from a project and how scale candidates are scored.

• Scan MIDI clips in a project and determine every scale they're compatible with
• Surface scale compatibility in the UI, filterable/sortable per project
• Apply a scale to a project's compatible MIDI clips
• Detect near-matches (a clip that fits a scale except for one or two notes)
• Packaged builds / releases
• Categorize a project's tracks (DRUMS, BASS, PERCUSSION, VOCALS, ...) from their names — not yet surfaced in the UI
• Mashup: filter projects down to a shared scale, select several of them, and get a picker of elements to pull from each into one new project — backend works for 2 projects (see Experimental above), UI in progress

MIT

Malstrom is an independent project, not affiliated with or endorsed by Ableton. Ableton and Live are trademarks of Ableton AG.