JRPG Translator Toolkit - with LaunchBox / Big Box plugin

retr0gamer42 · 2026-07-26T17:00:40Z

JRPG Translator Toolkit - with LaunchBox / Big Box plugin

Hi everyone,

over the last few months, I have been making a translation tool for my own use. After recently adding a plugin that integrates it more seamlessly with LaunchBox and Big Box, I thought it might be worth sharing here. Perhaps a few other people will find this combination convenient too.

I am not a professional programmer, but I have loved JRPGs since childhood and I remember playing games such as Ys IV on the PC Engine without understanding any of the Japanese and was always dreaming about a tool that could help me understand the story in the games better while I was actually playing them. So I compensated hopefully with passion what I lack in coding skill and actually Codex did a lot of the heavy lifting over the last weeks, but deciding how the workflows and interface should behave, testing everything extensively, and refining it through many iterations still required a considerable amount of time and patience, but it was a genuine passion project guided by a clear idea of how I personally wanted to experience untranslated Japanese games.

There are more mature and advanced translation tools available, and they will probably suit most people better, but I created this one because there was always something missing from my own preferred usage, so it is tailored around how I use LaunchBox, Big Box, emulators, controllers, translation overlays, and per-game Profiles, but perhaps someone else has been looking for a similar combination.

Modern AI translation also inspired me to finally begin studying Japanese seriously, previously, constantly stopping to search for individual words, kanji readings, and grammar made learning while playing feel too slow and disruptive for me. AI made that process much more efficient, which led to the optional Explainer overlay. It can take the latest Japanese dialogue and provide a separate breakdown of its vocabulary, readings, grammar, nuance, and context without replacing the normal translation. Optionally these can be automatically saved as a text file and I use them for reviews after playing and making flashcards in Anki.

What it does

JRPG Translator is a Windows application for translating Japanese games while playing. Its main features include:

Screenshot translation using OpenAI or Google Gemini models.
A compact translation overlay that can remain visible without taking focus away from the game.
Optional provide a Japanese transcript with kanji readings of the games dialogues.
Live translation of voiced dialogue using OpenAI Realtime or Gemini Live models.
A separate Explainer window for vocabulary, kanji readings, grammar, nuance, and cultural context.
Custom terminology overrides for character names, locations, and other game-specific terms for consistency.
Profiles containing prompts, capture settings, terminology, overlay appearance, and other game-specific preferences.
Keyboard hotkeys and optional direct XInput controller bindings.
Controller navigation throughout most of the control panel.
Independently customizable Translator and Explainer overlays.
Online update of OpenAIs and Geminis models through an online catalogue, no need to enter new models manually.
Multilanguage support: While the UI is English only you choose from multiple languages for the translation or explanation outputs.

The translation prompt determines whether the overlay shows only a translation or also includes the original transcript and kanji readings.

The Explainer is independent from the normal translation, so it can be opened only when additional help is wanted.

The live audio translation is pretty straight forward, just configure a model from OpenAI or Gemini and turn it on and off via a hotkey.

LaunchBox and Big Box integration

The main reason why I decided to share it here, the included preview plugin which adds JRPG Translator Setup... to a game’s LaunchBox context menu and Big Box details menu at the end.

For each game, it can:

Enable or disable JRPG Translator.
Select a JRPG Translator Profile per game.
Start JRPG Translator in the background when the game launches.
Apply the selected Profile to an already-running instance.
Optionally start JoyToKey or switch to a game-specific JoyToKey Profile.
Restore the previous JoyToKey Profile after the game closes.
Close only the program instances that were started by the plugin.

My goal was to make the process as close as possible to selecting a game in Big Box and starting it with the correct translation setup already prepared.

Beginner setup

For a straightforward first setup, I recommend the following:

Extract the main application to:
```
LaunchBox\Apps\JRPG Translator
```
Keeping it this way inside the LaunchBox root folder makes the installation portable and allows the plugin to find it more easily.
Before using the plugin, run JRPG Translator.exe manually at least once.

This is important because the plugin normally starts JRPG Translator in the background with its main window hidden. During the first manual launch, configure:
- Your OpenAI and/or Gemini API keys.
- The translation and explanation models.
- Your screenshot capture region or game window.
- Translation and explanation prompts.
- Keyboard hotkeys or direct controller bindings.
- Translator and Explainer overlay positions and appearance.
- Any game-specific terminology overrides.
- A unified Profile containing the finished setup.
You can do changes like for the capture region during gameplay but in particular, remember the hotkey for showing the control panel again. Otherwise, a first launch through the plugin may appear to do nothing because the main window is deliberately hidden to seamlessly start the game with only the translation window visible.
Install the LaunchBox plugin by extracting:
```
JRPG Translator Integration.zip
```
into the LaunchBox Plugins folder. The resulting location should be:
```
LaunchBox\Plugins\JRPG Translator Integration
```
Restart LaunchBox. Right-click a game and select JRPG Translator Setup.... Enable JRPG Translator for that game and choose the Profile created during the initial setup.
Start the game normally. The plugin should prepare JRPG Translator automatically and apply the selected Profile.

Suggested controller setup

JRPG Translator supports native direct controller bindings, but it was also designed with more advanced JoyToKey mappings in mind.

One arrangement I find particularly effective is assigning related functions to the same physical button depending on how long it is held. For example:

Normal press: explain the most recent Japanese dialogue.
Long press: show or hide the Explainer overlay.

Another possible combination is:

Normal press: translate Japanese text on the screen
Long press: show or hide the Translator overlay.

JoyToKey can distinguish between a normal and long press and send different keyboard shortcuts for each. This keeps the most frequently used translation and overlay functions available without requiring many separate controller buttons.

This is only a suggested arrangement. The application can also be used with ordinary keyboard hotkeys or its native direct controller bindings.

Configuration in the main window

The main JRPG Translator main window acts as the control panel for the application. Its tabs organize the settings for screenshot and audio translation, AI models and prompts, the Translator and Explainer overlays, terminology overrides, controls, API keys, and Profiles. Most changes are applied and saved automatically, so the setup can also be adjusted while testing it with a game.

The Screenshot Translation tab is normally the best place to begin after entering the API keys. Here you can select the AI provider, model and prompt, define the capture region, and configure how the translated text should be presented.

The Translation Window and Explanation Window tabs control the position, size, colors, transparency, and general appearance of the two overlays.

The Audio Translation tab configures live translation for spoken dialogue, such as voiced cutscenes or games without useful on-screen text. You can select the audio input, AI provider and real-time model, and choose from multiple supported output languages there as well. Once started, recognized dialogue is translated as it is heard and displayed in the Translator overlay.

The Controls tab lets you configure keyboard shortcuts or native controller bindings. Once the application is working as intended, the complete setup can be saved as a unified Profile, which can later be loaded manually or assigned to a game through the LaunchBox plugin.

Requirements and important notes

Windows 10 or Windows 11.
An OpenAI API key, a Google Gemini API key, or both.
Internet access for translation and explanation requests.
Screenshots or audio used for translation are sent to the selected API provider. Please review that provider’s current privacy and data-retention policies.
The LaunchBox / Big Box integration should still be considered a preview.
I have tested it with my own setup, but I cannot guarantee that it will work correctly with every emulator, controller, audio device, or Windows configuration.

About the API keys

JRPG Translator uses online AI models, so it needs an API key—a private access code that allows the application to send requests through your account and records the resulting usage. You can create one on the OpenAI API Keys page or through Google AI Studio for Gemini. Once you paste the key into the API Keys tab, the application uses it automatically; just remember to treat it like a password and never share it publicly.

You do not need a ChatGPT Plus, Gemini Advanced, or similar monthly subscription. API access is billed separately on a pay-as-you-go basis, using prepaid credit or periodic billing depending on the provider and account. If you stop using the application for a while, no new usage charges are generated. I have personally found the costs very reasonable: even when playing for a few hours on most days, I have so far never paid more than roughly €10 in a month. This is only my own experience—actual costs depend on the selected models and how frequently features such as screenshots, explanations, and audio translation are used. OpenAI billing information · Gemini API billing information

Since there is no subscription needed I recommend just getting an API key from both, but if you just want to use one I would recommend getting one from Gemini, at least for now their 3.5-Flash-Lite model for translation and their audio real time models give me the best balance of speed an accuracy but this of course can change again.

Download and documentation

Latest release: [INSERT GITHUB RELEASE LINK]
Source code and documentation:
https://github.com/retrogamer0815/jrpg-translator-toolkit
Current version: v0.9.2

The GitHub README contains more detailed installation, configuration, and troubleshooting information.

Bug reports and constructive feedback are welcome. Since I am not an experienced developer, I may not be able to solve every issue, but detailed reports would still be helpful.

I hope this may be useful to a few other people who enjoy exploring untranslated Japanese games.