Rootbly: AI Subtitles 4 youtub

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In-app purchases

About this app

Watch any YouTube video with AI-translated subtitles in the language you want.
Struggling with missing subtitles or poor auto-translate quality on foreign YouTube videos? RootblySub solves that.

✨ Key Features
🌐 AI Subtitle Translation
Paste a YouTube URL and our AI extracts and translates subtitles into your preferred language — fast and accurately.
🎬 Built-in Video Player
Watch videos and read translated subtitles in real time, all within the app.
🌍 15 Languages Supported
Korean · English · Japanese · Chinese (Simplified/Traditional) · Spanish · French · German · Portuguese · Russian · Arabic · Hindi · Indonesian · Thai · Vietnamese
🔗 Easy Sharing
Tap Share in the YouTube app and send the video directly to RootblySub.
📊 Job Tracking
Monitor translation progress in real time and get notified when it's done.

💡 Perfect For

Watching foreign YouTubers with subtitles in your language
Language learners who need translated subtitles
Anyone frustrated with low-quality auto-generated captions


🚀 How It Works

Paste a YouTube video URL
Choose your target language
Wait for the translation to complete
Watch with subtitles in the built-in player


Try it in guest mode first. Sign in with Google to unlock the full experience.

What’s new

🎉 File Upload Subtitles (BETA)

Generate subtitles without a YouTube URL! Upload your audio or video files directly and get AI-powered subtitles translated into your preferred language.

• Supported: MP4, MP3, WAV, MOV, MKV, FLAC, OGG, M4A, WebM, AVI
• Up to 3GB / 60 min
• Pro subscribers only

⚙️ Stability Improvements
• Failed jobs now show correct status
• Prevented duplicate retry requests