Frequently Asked Questions
Frequently Asked Questions
Section titled “Frequently Asked Questions”Common questions and answers about Subtide.
General Questions
Section titled “General Questions”What is Subtide?
Section titled “What is Subtide?”Subtide is an AI-powered browser extension that translates video subtitles in real-time. It works with YouTube, Twitch, and any website with video content.
Is Subtide free?
Section titled “Is Subtide free?”Yes, Subtide is completely free and open-source under the MIT License. However, you’ll need to provide your own API key for LLM translation services (OpenAI, OpenRouter, etc.) unless you run a local LLM.
What languages are supported?
Section titled “What languages are supported?”Subtide supports 13+ languages for translation:
| Language | Code |
|---|---|
| English | en |
| Spanish | es |
| French | fr |
| German | de |
| Portuguese | pt |
| Russian | ru |
| Italian | it |
| Japanese | ja |
| Korean | ko |
| Chinese (Simplified) | zh-CN |
| Chinese (Traditional) | zh-TW |
| Arabic | ar |
| Hindi | hi |
Whisper can transcribe 90+ languages, so videos in other languages can be translated to the supported target languages.
Does Subtide work offline?
Section titled “Does Subtide work offline?”Partially. You can run both the backend and LLM locally for fully offline operation:
However, you’ll still need internet to access the video content itself.
Costs & Pricing
Section titled “Costs & Pricing”How much does translation cost?
Section titled “How much does translation cost?”Costs depend on your API provider and model choice:
| Provider | Model | Approx. Cost per Video |
|---|---|---|
| OpenAI | gpt-4o-mini | $0.001 - $0.01 |
| OpenAI | gpt-4o | $0.01 - $0.10 |
| OpenRouter | Various | Varies by model |
| Local LLM | Any | Free (electricity only) |
Costs vary based on video length and subtitle density.
Can I use Subtide without paying?
Section titled “Can I use Subtide without paying?”Yes! You can:
- Use Tier 1 with existing YouTube captions (no Whisper needed)
- Run a local LLM with LM Studio or Ollama (free after hardware)
- Use free API tiers from some providers (limited usage)
What’s the cheapest setup?
Section titled “What’s the cheapest setup?”For the lowest cost:
- Use Tier 1 (uses existing captions when available)
- Use gpt-4o-mini (cheapest OpenAI model)
- Or run a local LLM for zero API costs
Technical Questions
Section titled “Technical Questions”Which tier should I use?
Section titled “Which tier should I use?”| Use Case | Recommended Tier |
|---|---|
| Videos with existing subtitles | Tier 1 |
| Videos without subtitles | Tier 2 |
| Shared/team deployment | Tier 3 |
| Real-time streaming subtitles | Tier 4 |
What’s the difference between Whisper backends?
Section titled “What’s the difference between Whisper backends?”| Backend | Best For | Performance |
|---|---|---|
| MLX | Apple Silicon Macs (M1/M2/M3/M4) | Fastest on Mac |
| Faster-Whisper | NVIDIA GPUs | Fastest on NVIDIA |
| OpenAI Whisper | CPU fallback | Slowest but universal |
What Whisper model should I use?
Section titled “What Whisper model should I use?”| Model | Memory | Quality | Speed | Best For |
|---|---|---|---|---|
tiny | ~1 GB | Basic | Fastest | Testing |
base | ~1 GB | Good | Fast | Quick translations |
small | ~2 GB | Better | Medium | Better accuracy |
medium | ~5 GB | Great | Slow | High quality |
large-v3-turbo | ~6 GB | Excellent | Fast | Recommended |
large-v3 | ~10 GB | Best | Slowest | Maximum quality |
Recommendation: Use large-v3-turbo for the best balance of speed and quality.
Can I use this with live streams?
Section titled “Can I use this with live streams?”Yes, but with limitations:
- YouTube Live: Supported via Live Translation mode
- Twitch: Supported for live streams
- Latency: Expect 5-15 seconds delay for transcription + translation
What video formats are supported?
Section titled “What video formats are supported?”Subtide works with any video using HTML5 <video> elements. This includes:
- YouTube (regular, Shorts, embedded)
- Twitch (live, VODs, clips)
- Most modern video players
Not supported:
- DRM-protected content (cannot access audio)
- Flash-based players (obsolete)
- Canvas-rendered video (non-standard)
Quality Questions
Section titled “Quality Questions”Why are my translations inaccurate?
Section titled “Why are my translations inaccurate?”Common causes and solutions:
- Poor audio quality → Use a larger Whisper model
- Multiple speakers → Enable speaker diarization
- Technical jargon → Use a more capable LLM (gpt-4o)
- Fast speech → Adjust playback speed
- Background noise → Whisper handles this well, but extreme cases may struggle
How can I improve translation quality?
Section titled “How can I improve translation quality?”- Use gpt-4o instead of gpt-4o-mini for complex content
- Use large-v3-turbo Whisper model
- Enable dual subtitles to verify translations
- For Asian languages, try Qwen models which excel at CJK
Why are subtitles out of sync?
Section titled “Why are subtitles out of sync?”- Adjust sync using the sync controls in the menu (+/- seconds)
- Reset position by double-clicking the subtitles
- Try streaming mode (Tier 4) for better sync
Platform-Specific Questions
Section titled “Platform-Specific Questions”Why doesn’t the translate button appear on YouTube?
Section titled “Why doesn’t the translate button appear on YouTube?”- Refresh the page after installing the extension
- Disable conflicting extensions that modify YouTube’s UI
- Check extension permissions in chrome://extensions
- Clear browser cache and reload
Do YouTube Shorts work differently?
Section titled “Do YouTube Shorts work differently?”Yes! Shorts use a pre-translation system:
- Videos are translated before you swipe to them
- A queue of 4+ videos is maintained ahead
- Subtitles appear instantly when you swipe
This compensates for the rapid swiping behavior of Shorts.
Does this work with YouTube Premium?
Section titled “Does this work with YouTube Premium?”Yes, Subtide works the same with or without YouTube Premium.
Can I use this on embedded YouTube videos?
Section titled “Can I use this on embedded YouTube videos?”Yes, Subtide detects embedded YouTube players on other websites. All features work the same.
Privacy & Security
Section titled “Privacy & Security”Does Subtide collect my data?
Section titled “Does Subtide collect my data?”No. Subtide:
- Does not collect personal data
- Does not track your viewing history
- Does not send data to third parties
- All processing happens locally or via your chosen API provider
Where is my API key stored?
Section titled “Where is my API key stored?”Your API key is stored locally in Chrome’s extension storage. It is:
- Never sent to Subtide servers
- Only sent to the API provider you configure
- Encrypted by Chrome’s storage API
Is the backend secure?
Section titled “Is the backend secure?”The backend:
- Runs locally by default
- Does not store any data permanently
- Only processes videos you explicitly translate
- Can be firewalled to localhost only
Troubleshooting
Section titled “Troubleshooting”The extension isn’t working
Section titled “The extension isn’t working”See our Troubleshooting Guide for solutions to common issues.
How do I report a bug?
Section titled “How do I report a bug?”- Check existing issues
- Open a new issue with:
- Browser and version
- Operating system
- Steps to reproduce
- Error messages (from browser console)
How do I request a feature?
Section titled “How do I request a feature?”Open a feature request on GitHub with:
- Clear description of the feature
- Use case / why it’s needed
- Any implementation ideas
Contributing
Section titled “Contributing”How can I contribute?
Section titled “How can I contribute?”See our Contributing Guide for:
- Development setup
- Code style guidelines
- Pull request process
- Areas needing help
Can I add support for a new platform?
Section titled “Can I add support for a new platform?”Yes! The extension architecture supports adding new platforms. See the generic player implementation as a template.
Can I add a new language?
Section titled “Can I add a new language?”Yes! Translation languages depend on the LLM capabilities. For UI languages, add translations to extension/_locales/.
More Questions?
Section titled “More Questions?”- Check the Troubleshooting Guide
- Browse GitHub Issues
- Open a new issue if your question isn’t answered