A browser extension that uses Whisper on your Mac to add subtitles to videos. Press Start to generate captions, with optional translation into Simplified Chinese.
Watching an interview without subtitles? Turn on Koe to read along as it plays.
Koe adds captions to video playing in a Chromium tab. Local recognition turns speech into text, with captions that follow the media timeline. Controls and status stay in the popup or side panel.
Opening a page or the controller does not start recognition. Stop ends the active capture session.
ON YOUR MACLocal recognition.
Koe Helper runs Whisper on your Mac. Local recognition does not send audio to DashScope.
WITH YOUR VIDEOCaptions follow playback.
Captions follow seeking, video changes and fullscreen. Only captions appear over the video.
02 / PRESS PLAYJAPANESE AUDIO · CHINESE CAPTIONS
Play a clip. Read along.
Press Start to hear the voice and follow along. Switch between original and translated captions.
Waiting for you to press Start
Japanese voice
声
KOE / LISTENING COMPANION
TRACK 01BEYOND THE WORDS
Japanese voice · 12 seconds
Press Start to see Japanese and Chinese captions.
A web demo with a synthesized Japanese voice and matching preset captions. It does not capture audio or run recognition. Actual captions follow your video.VOICEVOX:あいえるたん
03 / RECOGNITION & PRIVACYMODES & PRIVACY
Local by default. Cloud if needed.
Local mode uses Whisper on your Mac. Cloud mode requires your own DashScope API key.
WHISPER · ON YOUR MAC
Speech recognition on your Mac
Koe Helper runs Whisper large-v3. The first local session downloads an approximately 626 MB model, then reuses the local cache.
Recognition audio is not sent to DashScope.
macOS 26+ supports local Chinese translation with the required Apple language packs.
macOS 15–25 provides original captions in local mode.
Downloading the model and fetching online media still require a network connection. Apple language packs need to be installed separately.
Caption history and diagnostics Recent captions stay in browser session storage. Diagnostic logs record timing and errors, not caption text. Read the full privacy notes
04 / INSTALL KOESET UP KOE ON YOUR MAC
Download Koe. Run the installer.
Apple silicon Mac · macOS 15 or later Guided installation with ego-lite
Choose a download on GitHub Releases and follow that release's installation guide.
02
Run the installer
Double-click Install Koe.command. It selects the right Helper and sets up the extension in ego-lite.
03
Press Start
Open a video, click Koe, then press Start. The first local session downloads the recognition model.
Before you install
This developer preview is not Developer ID signed or Apple notarized. If macOS blocks the installer, Control-click the file, choose Open and confirm. Intel Macs are not supported. Koe is a browser extension with a macOS Helper, not a standalone Windows desktop app. Chrome needs a manual extension load. The extension interface is currently Simplified Chinese. Full installation guide
05 / COMMON QUESTIONSA FEW THINGS TO KNOW
Good questions.
Does Koe listen automatically?+
No. Opening pages, playing videos, changing settings or opening the controller does not start recognition. You explicitly start a session through Koe's controls or context menu. After you start, it follows media changes until you stop. Alt+K only opens the controller.
Does it work with every video?+
Not every video. Compatible public, unencrypted HLS VOD can use direct media processing. Other pages may use local tab-audio recognition when the browser permits capture. Koe does not bypass DRM or read browser cookies and authorization headers. Browser-internal pages cannot be captured. Helper support details
Which languages can it translate into?+
The current translation target is Simplified Chinese. On macOS 26+, install the required Apple language packs for local translation; on other supported macOS versions, DashScope offers optional cloud translation. Captions that reliably match the browser language stay as one original line by default. The demo does not imply translation between arbitrary languages.
How do I update or disable auto-loading?+
Download the latest release and rerun the installer to update. To disable ego-lite's extension auto-restore, run ~/Library/Application Support/Koe/Disable Koe Auto-Load.command. Auto-loading the extension does not start audio recognition. Check the installation guide for upgrades from older versions.
