babelive/windows

Babelive is a Windows desktop app, written in C# on .NET 9 and the Avalonia user-interface toolkit, that listens to whatever your computer is currently playing and translates it in real time. The audio can come from any program: a video call, a YouTube clip, a Spotify song, a Teams meeting. It captures the sound, sends it to an OpenAI realtime translation model called gpt-realtime-translate, plays the translated voice back through a speaker of your choice, and shows the original and translated text side by side in a floating, always-on-top lyric-style panel at the bottom of the screen. The README walks through the audio pipeline using a small diagram: Windows audio is captured with a loopback recorder, downmixed and resampled from 48 kHz to 24 kHz, packed into PCM16 format, and sent over a WebSocket connection to the OpenAI service. The model sends back translated audio plus running transcript snippets in both languages, which the app routes to the chosen playback device and to the overlay window. To install and run it, a user needs Windows 10 or 11, the .NET 9 SDK, and an OpenAI API key with access to the translation model. The commands "dotnet restore" then "dotnet run" build and start the app. A "dotnet publish" command produces a single self-contained Babelive.exe of roughly 80 to 90 MB. The API key is saved locally in a settings.json file and is only sent to the configured API endpoint. The interface lets you pick a target language, choose a capture source (all system audio or a specific app), pick a playback device, and adjust sliders for source ducking and translation volume. There are toggles for transcript-only mode, an alternate endpoint, echo suppression, and source muting. A record button writes timestamped folders containing the source audio as a WAV file, the translated audio as another WAV file, and matching SRT subtitle files for both languages. The README notes that Windows built-in players ignore external SRT for WAV files and suggests VLC or mpv for playback. A special section explains that Microsoft Teams and Skype block normal loopback for privacy, so Babelive can route their audio through VB-CABLE if it is installed. The README also mentions that the audio layer is being abstracted for a future macOS port.