# Glucose: complete reference

> Glucose is a modern video and audio player for Windows by DoublOne Studios (Finland). The latest version is v4.0.0, released 2026-10-24. Glucose 4 generates subtitles live as you watch and translates them on your own PC. It is pay what you want (from $0) and open source under EUPL-1.2. A shorter summary is at https://glucose.media/llms.txt.

Website: https://glucose.media
Download: https://glucose.media/download (Windows installer) or the Microsoft Store: https://apps.microsoft.com/detail/xpfm6mmmtq8132
Source code: https://github.com/rudi-q/glucose_media_player
Contact: support@glucose.media
Studio: DoublOne Studios, https://doubl.one, maintained in Finland

## What Glucose is

A video and audio player for Windows 10 and 11 that stays out of the way: controls hide during playback, it remembers where you stopped in every file, and its AI features run on your own PC. It is built with Rust, Tauri v2 and Svelte 5, and uses Whisper (whisper.cpp through whisper-rs) for speech recognition.

## New in Glucose 4

### Live subtitles
- Subtitles are generated while the video plays, for videos that have none. Turn them on from the subtitle menu (Generate with AI, then Live (real-time)), or have Glucose start them by itself (Settings, AI, Live Subtitles, "Auto-start when no subtitles are found").
- Glucose stays a few minutes ahead of playback. The seek bar shows the parts of the video that are ready.
- Skipping ahead starts generation from the new position; "Generating subtitles..." shows until the first line is ready.
- Generated subtitles are saved per video, audio track and language, so a video you return to doesn't have to be processed again.
- "When subtitles aren't ready yet": keep playing, or "Pause until ready".
- Runs on your PC with Whisper. Nothing is uploaded.

### Live translation
- Translates live subtitles from English into German, French, Spanish, Italian, Dutch, Russian or Turkish, and from any of these seven into English (14 language pairs).
- Each language pair is a separate download of about 20 MB (Settings, AI, Translation models) and runs offline on your PC.
- "Show original subtitles too" shows the original line, smaller, under the translation. Useful for language learners.

### Smart subtitle position
- With Placement set to Smart (in the subtitle style panel or Settings, Player), a cue moves to the top when the bottom of the picture has on-screen text, a face, or a bright or busy area, and comes back down when the bottom is clear.
- When a face and on-screen text can't both be avoided, the text is kept clear.
- Placement set to Fixed keeps subtitles exactly where the Position slider puts them.

### Features tab (hardware check)
- Settings, Features checks the processor, threads, memory and graphics, and runs a short speech-recognition speed test.
- Each heavy feature gets a verdict: Works well, May be slow, Not recommended, or Not tested. It covers live subtitles, live translation, smart subtitle position and AI subtitles with the Large model.
- Features found "Not recommended" are turned off after the first check, and can still be turned on in their settings.

### Also in Glucose 4
- Subtitle files nearby: subtitle files whose names differ from the video (another release of the same film, a Subs folder, language tags) are offered in the subtitle menu.
- A "What's new" screen after updating.
- Fixes: no window freeze while a OneDrive or cloud-folder video downloads, file pickers in front of the player in fullscreen and picture-in-picture, full folder paths in Settings, Library, and "Report issue" leaves file paths out of reports.

## All features

### AI and subtitles
- Live subtitles and live translation (above).
- Full-video transcription: generate subtitles for a whole video at once with the Tiny (~75 MB, fastest), Small (~466 MB, balanced) or Large V3 Turbo (~574 MB, most accurate) model, formatted to Netflix-style timing and line-length rules.
- Automatic language detection.
- Loads SRT, VTT, ASS, SSA and SUB files automatically, including nearby files with different names, and extracts subtitle tracks embedded in MKV and MP4 files.
- Custom subtitle styles: presets (Classic, Cinema, Bold, Frosted and more) and live controls for font, size, colour, background and position.
- Toggle subtitles with C or S.

### Playback
- Windowed (resizable), fullscreen and cinematic view modes. Cinematic mode puts a blurred copy of the video behind it.
- Picture-in-Picture: a small draggable window that snaps to corners.
- "Up Next" overlay: a countdown to the next episode in the folder.
- Resume playback: the position in every video and audio file is saved automatically.
- Seek-bar frame previews on hover.
- Volume boost up to 200%, and smooth volume fades on play and pause.
- Multiple audio tracks: switch between embedded tracks during playback.
- Plays more formats, such as .ts, .m2ts and .3gp, and converts files the player can't play directly (FFmpeg).

### Library
- A media gallery that scans Videos, Downloads and Desktop, plus any folders you add.
- Hover previews that start from your watch position, progress on every tile, and sections such as "Today" and "Yesterday".
- Cloud-only file badges (detected locally, without uploading anything).

### Audio
- A dedicated audio player with a real-time visualizer for MP3, FLAC, WAV, AAC, OGG, Opus, M4A, AIFF and WMA.

### System
- Updates are checked once a day and installed automatically.
- File association: set Glucose as the default player and open files from File Explorer, or drag and drop.
- GPU-accelerated rendering. No telemetry, no ads, no account.

## Formats

- Video: MP4, MKV, AVI, MOV, WebM, WMV, FLV, M4V, MPG, MPEG, OGV, TS, M2TS, 3GP (and others through conversion)
- Audio: MP3, FLAC, WAV, AAC, OGG, Opus, M4A, AIFF, WMA
- Subtitles: SRT, VTT, ASS, SSA, SUB, plus embedded tracks in MKV and MP4

## Keyboard shortcuts

- Space or K: play / pause
- Left / Right: seek 5 seconds back / forward
- 0 to 9: jump to 0% to 90% of the file
- Up / Down: volume up / down
- M: mute / unmute
- C or S: toggle subtitles
- F: toggle fullscreen
- P: toggle Picture-in-Picture
- Backspace: return to the gallery
- Escape: leave fullscreen or Picture-in-Picture, otherwise return to the gallery
- In the gallery: arrow keys move between tiles, Enter or Space opens the selected file

## Requirements

- Windows 10 or 11, 64-bit. The installer is about 9.5 MB; allow about 50 MB for the app.
- Optional AI downloads: one speech model (75 MB to 574 MB) for subtitles, and about 20 MB per translation language pair.
- How fast the AI features run depends on the PC; Settings, Features shows what to expect.
- No internet connection is needed for playback, transcription or translation once models are downloaded.

## Price and license

- Pay what you want, starting at $0. Every feature is included whatever you pay. Payments go through Polar. Optional support: https://glucose.media/donate
- The app is open source under the European Union Public Licence 1.2 (EUPL-1.2), governed by Finnish law.

## Privacy

- Glucose collects no data: no analytics, crash reports, telemetry, tracking or accounts.
- Network use is limited to the daily update check (GitHub releases API) and the AI models you choose to download. Nothing about you or your files is included.
- Media files, watch history, generated subtitles and translations stay on your PC.

## FAQ

Q: Why is it called Glucose?
A: 'Glucose' is a play on "glued, 'coz." Glued to it because the playback experience is that good.

Q: Which formats are supported?
A: Common video formats like MP4, MKV, AVI, MOV, WebM, WMV, TS, M2TS and 3GP, and Glucose converts files it can't play directly. Audio formats including MP3, FLAC, WAV, AAC, OGG, and M4A. Subtitle files (SRT, VTT, ASS, SSA, SUB) load automatically, even when their names don't exactly match the video, and Glucose extracts subtitle tracks embedded in MKV and MP4 files.

Q: Does it remember where I stopped?
A: Yes. It saves your position in every file automatically, video and audio. Open it again and it picks up from the same second. There's nothing to turn on.

Q: How do live subtitles work?
A: Turn them on from the subtitle menu (Generate with AI, then Live), or let Glucose start them by itself when a video has none. Whisper generates them on your PC while the video plays, a few minutes ahead of you. The seek bar shows how far they're ready, they follow when you skip ahead, and they're saved, so the next time you watch they're already there. You can also generate subtitles for a whole video at once.

Q: Which languages can it translate?
A: Live subtitles translate between English and German, French, Spanish, Italian, Dutch, Russian or Turkish: English speech into any of those seven, or speech in any of them into English. Each language pair is a one-time download of about 20 MB and runs on your PC. Turn on "Show original subtitles too" to keep the original line under the translation.

Q: Does it need the internet?
A: Only to download Glucose, its updates and the AI models you choose. Playback, transcription and translation all run on your PC, offline. Nothing about you or your videos is uploaded.

Q: Will the AI features run well on my PC?
A: Open Settings, then Features. Glucose checks your processor, memory and graphics, runs a short speed test, and tells you which features (live subtitles, translation, smart subtitle position) will work well, may be slow, or aren't recommended on your PC.

Q: Is it free to use?
A: Yes. Glucose is pay what you want: pay nothing, or whatever it's worth to you. Every feature is included either way.

Q: Is Glucose open source?
A: Yes. Glucose is open source under the EUPL-1.2 license. You can view the source code and contribute on GitHub: https://github.com/rudi-q/glucose_media_player.

Q: What are the system requirements?
A: Windows 10 or newer (64-bit). The installer is about 9.5 MB. The AI features need a speech model (75 MB to 574 MB) and, for translation, about 20 MB per language pair. Settings, then Features, shows how well they'll run on your PC.

Q: Will there be macOS or Linux versions?
A: Glucose currently targets Windows. Cross-platform builds may come later — follow the GitHub repo for updates.

## Glucose for Browser

A separate product by the same studio: a browser extension that translates the captions of the videos you stream into your language, on your device. In the browser and its store listing it is called "Glucose Subtitles". Install: https://chromewebstore.google.com/detail/glucose-subtitles/ibacgilfjdcacbbeajiafdjmecnlmadi (Chrome Web Store; works in Chrome, Edge, Brave, Arc, Opera, Vivaldi and other Chromium browsers) or https://apps.apple.com/us/app/glucose-subtitles/id6826599420?mt=12 (Mac App Store, for Safari on macOS). Page: https://glucose.media/browser. Privacy policy: https://glucose.media/browser/privacy. Video: https://www.youtube.com/watch?v=xIgDMu33qnQ

- How it works: turn on the site's captions as usual; the extension shows them translated in the same place, with the original line smaller underneath (can be turned off). Alt+Shift+T turns translation on and off.
- Languages: captions are translated into the browser's language by default; another language can be picked from the extension's icon, along with the captions' own language if detection gets it wrong. Finnish to English works straight away; other language pairs need a one-time download (about 110 MB) that stays on the device.
- Translates whole sentences rather than word by word, and translates upcoming sentences before they appear. Lines already in your language are left as they are.
- A short credit names the language when a video starts translating ("Finnish subtitles by Glucose"); it can be turned off. Caption size, height and background darkness can be changed.
- Runs on the device: no server, no account, and captions are never sent to DoublOne Studios.
- Sites: YouTube, Netflix, Prime Video, Disney+, Max, Hulu, Vimeo and Udemy, players built on JW Player, Plyr, Shaka, Bitmovin and Video.js, Yle Areena, and any player that uses the video's own text tracks.
- Browsers: Chrome 116 or newer, Edge, Brave, Arc, Opera, Vivaldi and other Chromium browsers, and Safari on macOS. Firefox is not supported yet.
- Limits: captions burned into the picture or drawn on a canvas (Crunchyroll) can't be read.
- Price: free for everyone through 11 November 2026, during the preview. Pricing after that may change; see the store listing.
- Glucose for Browser is proprietary software by DoublOne Studios. It is not open source.

## Videos

- Introducing Glucose 4 (100 s): https://www.youtube.com/watch?v=n1S8kM3Qp7s. Footage from Sintel, © Blender Foundation, CC BY 3.0.
- Glucose for Browser (65 s): https://www.youtube.com/watch?v=xIgDMu33qnQ. Footage from Tears of Steel, © Blender Foundation, CC BY 3.0.

## Troubleshooting

### Glucose media player

Q: A file will not play.
A: Glucose plays common video and audio formats, and converts files it can't play directly. Check that you are on Windows 10 or newer (64-bit), and tell us the file type if it still fails.

Q: Subtitles are not showing.
A: Press C or S to toggle them. Glucose reads SRT, VTT, ASS, SSA and SUB files, including ones whose names differ from the video, and subtitle tracks embedded in MKV and MP4 files. If a video has none, choose Generate with AI in the subtitle menu.

Q: Live subtitles fall behind the video.
A: Open Settings › Features to see how well live subtitles run on your PC. In Settings › AI, set When subtitles aren't ready yet to Pause until ready to have the video wait for them.

Q: Live translation is not showing.
A: Each language pair is a one-time download of about 20 MB. Download it in Settings › AI, under Translation models, then choose the language in the subtitle menu. Translation is between English and German, French, Spanish, Italian, Dutch, Russian or Turkish.

Q: Subtitles jump to the top of the picture.
A: That is smart subtitle position: it moves a subtitle up when the bottom of the picture has a face, on-screen text or a bright area. Set Placement to Fixed in the subtitle style panel to keep subtitles where you put them.

Q: A feature is turned off after the hardware check.
A: The Features tab turns off features it finds "Not recommended" for your PC, so playback stays smooth. You can still turn them back on in their settings.

Q: AI subtitle generation is slow or inaccurate.
A: Whisper runs on your own machine. Smaller models are faster, larger ones are more accurate, so try a different model size.

Q: It did not resume where I stopped.
A: Glucose saves your position in each file automatically. Moving or renaming a file may make it look like a new one.

### Glucose for Browser

Q: Nothing is being translated.
A: Turn on the site's own captions first. The extension translates what the player shows, so it cannot read captions burned into the picture or drawn on a canvas (Crunchyroll). A player without text tracks that is not on the supported list is left alone.

Q: It translates from the wrong language.
A: Click the extension icon and set the language the captions are in. Detection can get it wrong.

Q: The first translation takes a while.
A: Most language pairs need a one-time download of about 110 MB, kept on your device afterwards. Use the Download button in the popup to fetch it ahead of time. Finnish to English works straight away.

Q: I cannot find the extension icon.
A: Pin it from the puzzle-piece menu in your toolbar. Alt+Shift+T turns translation on and off.


## Release history

### v4.0.0 (2026-10-24): Live Subtitles, Real-Time Translation & Smart Positioning

Glucose 4 introduces on-device live subtitle generation with Whisper, real-time translation across 14 language pairs, smart subtitle positioning that avoids faces and screen clutter, and an automated PC capability profiler

New:
- Live Subtitles:
  - Real-time subtitle generation during playback for videos without existing subtitle tracks
  - 100% private, on-device transcription with Whisper — no audio data ever leaves your computer
  - Adaptive 20-second chunking with up to 8-thread multi-core acceleration
  - Per-video subtitle cache indexed by media file, audio track, and language for instant reloads without re-processing
  - Translucent seek bar coverage indicator displaying generated subtitle progress in real time
  - Optional 'Pause until ready' playback setting that holds the video automatically if transcription falls behind
  - Auto-start preference in Settings to automatically generate subtitles when no subtitles are found
  - Netflix-standard cue timing and reading-speed line formatting for crisp, readable subtitles
- Live Translation:
  - Real-time on-device subtitle translation between English and German, French, Spanish, Italian, Dutch, Russian, or Turkish (14 language pairs)
  - Compact, lightweight translation models (~20 MB each) powered by CTranslate2 with int8 execution
  - One-click model management in Settings with SHA-256 integrity verification, safe background downloads, and easy removal
  - Bilingual subtitle mode ('Show original subtitles too') displaying original speech lines beneath translated subtitles
  - Sentence-level context grouping ensures natural sentence flow before mapping timing back to individual speech cues
- Smart Subtitle Position:
  - Dynamic subtitle placement automatically shifts subtitles to the top when the bottom of the screen has faces, text, or visual activity
  - Integrated on-device face detection (YuNet ONNX) ensures subtitles never obstruct actors' faces or expressions
  - New 'Smart' placement option in the subtitle style editor and settings, with fixed-position fallback
- Hardware & Diagnostics:
  - Features tab in Settings benchmarks CPU threads, RAM, and GPU capabilities with practical compatibility verdicts
  - Clear feature advice ('Works well', 'May be slow', 'Not recommended') sets realistic expectations for heavy AI workloads
  - Automatic silent background check runs shortly after onboarding to adapt default settings safely without playback interruption
  - Contextual performance warnings appear next to settings when a feature may stress your hardware
- Subtitles & Library:
  - Nearby subtitle file matching detects external subtitle files in the video's directory or Subs folder even with differing release tags or episode naming
  - Quick-access 'Subtitle files nearby' section in the subtitle menu for instant selection
  - Settings → Library now displays full folder paths for allowed locations

Improved:
- Interactive 'What's new in Glucose 4' update screen highlighting key capabilities with direct setup shortcuts
- Hardened asset streaming protocol with HTTP range requests and restricted media-only file access
- Native file dialogs now consistently open in front of fullscreen and picture-in-picture windows

Fixed:
- Eliminated window freezing when playing media stored in cloud-synced folders (OneDrive, iCloud)
- Replaced generic error screens with a dedicated error recovery dialog featuring safe quit and privacy-preserving issue reporting
- Fixed speech model concurrency and cancellation to prevent duplicate loading, stale subtitle events, and audio scrubbing leaks
- Hardened cue generation for unspaced languages, special characters, and edge-case word timestamps

Earlier releases:
- v3.7.1 (2026-07-20): Fullscreen Stability & Window Event Debouncing. Resolves window freezing during fullscreen focus switching and Win+D minimize, with debounced window events to eliminate IPC bottlenecks
- v3.7.0 (2026-06-19): Resizable Windowed App & Audio Fullscreen. Glucose is now a proper resizable window instead of a fullscreen overlay, with custom chrome, native fullscreen, and full parity between the audio and video players
- v3.6.1 (2026-06-02): Large Media Handling & Reliable Hover Controls. Controls auto-hide is now smarter, cursor hides in sync with controls, and large multi-GB files get properly scaled timeouts and memory-efficient streaming
- v3.6.0 (2026-05-21): Custom Subtitle Styles. Full subtitle rendering customization with presets, a live style editor, and persistent settings
- v3.5.1 (2026-05-15): Subtitle Hardening & UX Polish. Significant reliability improvements for AI subtitles, cancellation support, and better view mode persistence
- v3.5.0 (2026-05-13): Onboarding, Playback Settings & Watch History. First-run onboarding, configurable player behavior, Up Next overlay, and smarter watch history management
- v3.4.0 (2026-05-02): FFmpeg Management & Codec Detection. Advanced external tool configuration and intelligent codec warnings
- v3.3.1 (2026-04-28): PiP Refinement & Navigation UX. Enhanced Picture-in-Picture controls and more intuitive keyboard handling
- v3.3.0 (2026-04-27): Major Feature Release: Custom Libraries & Smart Previews. A massive update introducing custom library folders, intelligent hover previews, and a complete gallery overhaul
- v3.2.1 (2026-04-25): Dynamic FFmpeg Resolution. Improved robustness of external tool detection and path handling
- v3.2.0 (2026-04-23): Multi-Audio Track Support. Support for embedded audio tracks and seamless track switching
- v3.1.0 (2026-04-21): Settings Overhaul & Design Standardization. Major UI/UX upgrade with a new settings interface and standardized component system
- v3.0.0 (2026-04-14): Volume Booster, MKV Subtitles & Audio Visualizer. Major release with new audio features and advanced subtitle support
- v2.7.0 (2025-11-24): Enhanced Picture-in-Picture Mode. Improved PIP mode with draggable window and better UX
- v2.6.0 (2025-11-02): Picture-in-Picture Mode. Add floating window capability for multitasking
- v2.5.0 (2025-10-24): Automated Dependency Management. Added Dependabot configuration for automated updates
- v2.4.0 (2025-10-10): Subtitle Language Selection. Select language for AI-generated subtitles and route improvements
- v2.3.1 (2025-10-09): Auto-Update System. Tauri-based updater for automatic application updates
- v2.3.0 (2025-10-08): AI-Generated Subtitles. AI-powered subtitle generation using Whisper and UI improvements
- v2.2.0 (2025-10-08): Initial Release (v2.x). Foundation for modern subtitle and video features
- v0.3.0 (2025-10-07): GitHub Actions & Documentation. CI/CD pipeline and improved documentation
- v0.2.0 (2025-10-06): Initial Alpha Release. First public release with core video player functionality

Full changelog: https://glucose.media/changelog