SubFlex - Subtitle Controller by Extension Flex

SubFlex is an advanced subtitle player and synchronization tool for Firefox, inspired by Substital, featuring a breakthrough Dynamic Multi-Point Synchronization Engine.

Never abandon a movie or video again because of out-of-sync subtitles!

🌟 KEY FEATURES:

⚡ Dynamic Multi-Point Sync (Anchor Points)
Standard subtitle tools only let you add a fixed delay (+2s or -1s). But if a YouTube upload, movie cut, or TV episode has cut scenes or commercials, fixed offsets break completely! With SubFlex, drop Sync Anchors at any point in the video to instantly re-align subsequent dialogue lines without affecting earlier scenes.

📜 Visual Dialogue Scrubber & 1-Click Sync
Browse the full dialogue transcript in a sleek slide-out drawer. Search spoken keywords, jump directly to that line in the video, or click "Sync Here" to lock dialogue to the current playback timestamp.

⏩ Subtitle Speed Multiplier (Drift Correction)
Fix gradual subtitle drift caused by frame rate differences (e.g. 23.976 FPS Film vs 25 FPS PAL) using speed toggles (0.95x, 1.0x, 1.042x).

📂 Drag-and-Drop Subtitle Files
Drag and drop any .srt or .vtt file directly onto any video on any webpage. Files are parsed instantly and 100% locally in your browser memory.

🔍 Built-in Subtitle Search
Search and download subtitles directly within the player interface.

🎨 Full Subtitle Customization
Adjust font size, text color, background transparency, and positioning to your exact viewing preference.

🔒 100% Private & Local
SubFlex never tracks your browsing history or collects personal data. All subtitle processing happens locally on your computer.