Audio Codex

A simple desktop tool to browse, preview, and extract sounds from Bungie's Marathon (2025), in the spirit of MIDA and Deimos.

It reads the game's Tiger Engine .pkg packages directly (AES‑128‑GCM decryption + Oodle/Kraken decompression), finds every Wwise audio file, and lets you play it, view a waveform, inspect metadata, and export to WAV — individually or in bulk.

Features

• Browse 58k+ sounds across all packages, with instant search by tag id / package.
• Group by Package or Soundbank — soundbanks are reconstructed by parsing each Wwise bank's HIRC chunk and linking the WEM source ids it references (~93% of sounds get grouped under their owning bank).
• Media player — click a sound to play immediately; Space toggles play/pause; click the waveform to seek; volume slider.
• List rows show duration + a faint mini‑waveform; multi‑select for export.
• Metadata per sound: codec, channels, sample rate, duration, size, source package, tag id.
• Export the selected/multi‑selected sounds, the current filtered list, or everything, to WAV.

Requirements

• Windows x64 and a .NET 8 runtime (already present on most dev machines; otherwise winget install Microsoft.DotNet.DesktopRuntime.8).
• A local Marathon install — the tool uses the game's own bin\x64\oo2core_9_win64.dll (Oodle) to decompress packages. Nothing is redistributed.
• vgmstream for decoding Wwise audio — bundled in tools/vgmstream/ and copied next to the app automatically.

Running

Run.bat            # launches the Release build

or from source:

dotnet run --project src/App/MarathonAudio.App.csproj -c Release

Setup / packaging

This tool is C#/.NET — it does not use Rust, so no Rust toolchain is required.

• Fresh machine, from source: powershell -ExecutionPolicy Bypass -File scripts\setup.ps1 installs the .NET 8 SDK (via winget) if missing, downloads vgmstream if missing, and builds.
• Standalone, no .NET install needed: powershell -ExecutionPolicy Bypass -File scripts\publish.ps1 produces a self‑contained build in publish\ — zip that folder and it runs on any Windows x64 machine (the user still needs a Marathon install for the Oodle DLL).

On first launch, the game folder is auto‑detected at A:\Steam\steamapps\common\Marathon. If yours is elsewhere, click Browse… and pick the Marathon install folder (the one containing packages\ and bin\). Then click Load sounds.

How it works

.pkg  ──►  parse header / entry table / block table        (Tiger/TigerPackage.cs)
      ──►  AES‑128‑GCM decrypt + Oodle (oo2core_9) inflate  (per 0x40000 block, on demand)
      ──►  Wwise WEM (RIFF/WAVE, codec 0xFFFF Vorbis)
      ──►  vgmstream  ──►  WAV  ──►  NAudio playback + waveform peaks

• Audio files are entries of type 26 / subtype 7; Wwise soundbanks are 26 / 6.
• Packages are streamed block‑by‑block from disk, so indexing stays light on memory even though some packages are ~700 MB.

Fonts

The UI uses the game's own typefaces — PP Fraktion Mono (body/data) and MarathonShapiro Wide 65 (titles) — for an in‑game look, the same fonts MIDA uses. These are commercial fonts shipped with the game (font entries are type 24/0, embedded OTFs in the packages), so they are not committed to this repo. The app falls back to a system font when they're absent. To restore the in‑game look, drop the OTFs into src/App/Assets/Fonts/ as PPFraktionMono-Regular.otf, PPFraktionMono-Medium.otf, PPFraktionMono-Bold.otf, and MarathonShapiroWide65.otf (extract them from your own Marathon install). Prebuilt release binaries embed them for convenience.

A note on names

Retail Marathon strips human‑readable sound names — its Wwise soundbanks contain only BKHD + HIRC chunks (no STID name tables), and the alpha‑era metadata tags MIDA used are not present. So by default sounds are labelled by tag id, grouped under their soundbank (Bank XXXXXXXX), with full audio metadata.

Each sound and bank still has its Wwise id (an FNV‑1 hash of the original name). Drop a wordlist.txt next to the executable and the app reverses those ids MIDA‑style — every match turns a Bank ABCD… / hash label into the real name. Without a wordlist, the ids can't be reversed, so labels stay hash‑based (this is the same limitation MIDA has on retail).

Project layout

src/Tiger/        Package reader, decryption, Oodle, vgmstream wrapper, WEM metadata, indexer
src/App/          Avalonia UI (browser, player, waveform, export)
src/Probe/        Console harness used to validate the pipeline
tools/vgmstream/  Bundled decoder (https://vgmstream.org)

Reference projects: MIDA (DeltaDesigns) and Deimos (cohaereo); package format constants cross‑checked against the open‑source tiger‑pkg crate (v4nguard).