Install Dubstack
Chrome grants access only to YouTube, Netflix, and Netflix subtitle files.
Chrome extension · Requires a captioned YouTube video
Turn one YouTube caption track into two lines.
Dubstack can use YouTube auto-translate for the second language and keeps rolling captions paired before they appear.
Human-made captions are usually cleaner than automatic captions.
Set up YouTube
Start with a video that has captions.
Play a captioned video
Open the YouTube CC menu first if you want to confirm which source tracks exist.
Choose the two languages
Pick the source caption and a translation. Dubstack can request YouTube auto-translate when needed.
Use the in-player pill
Turn Dubstack on for the video. Turning it off restores the CC state you chose.
Rolling auto-captions
Both lines arrive together or neither does.
Automatic captions can change several times while a person is speaking. Dubstack waits for a complete translated pair instead of flashing a source-only line.
The learning-language caption remains the visual anchor.
Rolling caption updates are translated in order rather than racing each other.
Dubstack remembers whether it enabled captions or you selected them yourself.
Caption quality
Good input still matters.
When a creator uploads human-made captions, choose them. Automatic captions can merge several spoken phrases into one long block and may mishear names or accents.
Dubstack preserves YouTube's timing rather than inventing new dialogue. That keeps the extension responsive, but it cannot correct every transcription mistake.
Videos with no caption track are not supported. The normal YouTube player continues to work unchanged.
Shorts
The same subtitle controls apply
Dubstack detects YouTube Shorts sessions and resets when you move to another short.
Keyboard
Replay without finding the timeline
Alt-R returns to the start of the active subtitle line, including in fullscreen.