Replace any voice line, music track, ambience or sound effect in Batman: Arkham City (PC, Steam) with your own audio (by name, from a file or a recording) and edit subtitles and menu text, with one-click revert. No Wwise, no game patch, no external programs.

Unheard City (app/, user guide): the desktop editor for Windows and Linux. Browse and search all ~21,000 sounds of one language (its voice lines, music, ambience, and the effects stored inside soundbanks: footsteps, foley, combat, weapons, UI), filter by category and character, listen, replace or record, apply and revert. Edit subtitles (linked to their speech lines) and the menu text in their own sections. One Language setting (default: the game's) applies to sounds, subtitles and menu text.
ackit (ackit/): the Python library and command-line tool behind it.

How it works in one paragraph: the game's Wwise 2011.1 decoder only knows the standard Vorbis codebooks, so ackit encodes with libvorbis and rewrites the stream into exactly the layout the game expects (codebook IDs, packet format, seek table, header hash and memory size reversed from the game), then writes it in place into the .wad archives, the soundbanks and the game's compressed .upk packages (ackit reads and patches them itself), keeping the original files in a store for exact reverts. Subtitles live in the packages too, menu text in the localization files. Details in docs/.

Install

Editor (users), Windows: unzip UnheardCity-<version>-windows-amd64.zip and double-click Install.cmd. It installs for your user (no admin rights), adds a Start menu shortcut and an entry in Settings > Apps for uninstalling. Or skip installing and run UnheardCity.exe straight from the unzipped folder.
Editor (users), Linux: unpack the .tar.gz and run UnheardCity.
Nothing else is needed (no Python, no Wwise, no ffmpeg). To build it yourself: docs/building.md.

Toolkit (developers): Python 3.10+:

python -m venv .venv && .venv/Scripts/activate        # Linux: source .venv/bin/activate
pip install -e .[app,dev,verify]                       # app = editor, dev = tests/packaging, verify = in-game test
python -m app.main                                     # run the editor from source

Quick start (command line)

ackit find joker tape                             # search by name, category or character
ackit extract Speech_TAPE_JOKER_1_04 orig.wav     # listen to the original (a line has one name in every language)
ackit replace Speech_TAPE_JOKER_1_04 my_line.wav --match-loudness
ackit revert Speech_TAPE_JOKER_1_04               # or: ackit revert --all
ackit text find --lang ITA protocollo            # subtitles and menu texts (keys SUB:... / MENU:...)
ackit text set "MENU:ITA:FRONTEND.ITA:Menu:Start" "Premi Invio"

More: ackit status, ackit list --character Joker, ackit export-mod my.acmod / ackit import-mod, ackit verify (offline self-check), ackit verify --catalog (catalog vs game files), ackit game (detected install, language, store). ackit -h lists all commands. The game folder is found through Steam (Windows, Linux, Flatpak, Proton); otherwise pass --game DIR.

Rules worth knowing: speech/effects replacements must fit in the original's size (the tool squeezes or refuses with the maximum length); music can be any length. Subtitles must fit the original text's length (menu text: any length). Close the game before writing.

Where things are

ackit/          library + CLI   (formats, encoder, injector, catalog, originals store, workspace)
ackit/verify/   offline self-check, in-game test harness (Windows, WinDbg)
app/            Unheard City (PySide6)
tests/          pytest suite (synthetic game data; real-game tests run when the game is installed)
data/catalog/   sound catalogs (CSV), character lists (source/), schema in data/catalog/README.md
docs/           formats, reverse engineering, decisions, categories, user guide, building
tools/          catalog builder, real-game e2e checks (e2e_editor.py, e2e_features.py), packaging
                (build_app.py, installer/), artwork, license and screenshot scripts
NOTES.md        project status and working notes; CLAUDE.md: guidance for AI sessions

Tests: pytest (the real-game tests are skipped when the game is not installed). Real-game write round trips (no game launch): python tools/e2e_features.py [--lang all], python tools/e2e_editor.py. In-game tests (Windows, Steam running, WinDbg installed): ackit verify --ingame, --ingame --banks, --ingame --texts.