LiveSubReal-time subtitles for English and Japanese audio, entirely in your browser

1. Set up

Press "Start" to begin.
What you watch Recommended Why
Live streams and broadcasts Balanced Subtitles keep up
Recorded video Accurate Better with names
Slower computer Light Uses the least power
You can change this at any time, even while subtitles are running.

Pressing "Start" opens a sharing dialog. Pick the tab with your video and tick "Also share tab audio". Works in Chrome and Edge on desktop.

2. Display

3. Word list (optional)

List names that are often misheard, one per line. What we hear is corrected to your spelling. Add each form you expect, such as both “Fable” and “Fable 5.1”. Japanese entries need 3 characters, English ones 4.

4. Translation

Subtitles

Subtitles will appear here.
Press “Start (share a tab)”, then pick the tab that is playing.

Step-by-step guides

Walkthroughs for the situations people use this in, including where people get stuck.

Frequently asked questions

Does it cost anything?
No. There is no time limit either. Speech recognition runs on your own computer, so there is no per-minute cost to pass on to you.
Do I need to install anything or sign up?
Neither. Just open the page in your browser. The first run downloads the speech recognition model (73MB on the balanced setting); after that it is reused.
Which browsers and devices work?
Chrome or Microsoft Edge on a computer. Safari and Firefox are not supported, and phones cannot share tab audio, so mobile does not work.
Is my audio sent anywhere?
No. Recognition happens entirely inside your browser. We only receive anonymous counts of how often features are used — never audio, transcripts or translations.
Does it work outside YouTube?
Yes. There is no list of supported sites. If a browser tab is playing sound — a livestream, a lecture, an online meeting — it can be subtitled.
What should I check if no subtitles appear?
Check that “Also share tab audio” was ticked in the sharing dialog — that is the cause almost every time. You also need to pick the “Chrome Tab” section rather than the whole screen.
Can it go from Japanese to English?
Yes. Use “Translate from / to” to switch between English→Japanese and Japanese→English. You can switch while subtitles are running; the change applies from the next sentence.
Faint text appears and changes before the subtitle
That is not a fault. While someone is still speaking, we show a running guess from the audio so far. It is replaced by the finished subtitle once the sentence ends, so you spend less time waiting.
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Getting started — about 3 minutes

This page listens to the audio of a tab you share and turns it into subtitles. It can go English to Japanese or Japanese to English, switched in step 2. The audio is processed on your own computer and is never sent anywhere.

Before you start

Steps

  1. Open the video in another tab. YouTube, a course with no subtitles, an online meeting — anything works. You do not need to play it yet.
  2. Come back here and press “Start (share a tab)”. On the first run the download begins now. Wait until the status at the top says it is ready.
  3. In the sharing dialog, choose “Chrome Tab” at the top and click your video tab.
  4. Tick “Also share tab audio” at the bottom left. Without it only the picture is shared and no subtitles appear. This is the step people miss most.
  5. Press “Share”.
  6. Go back to the video and play it. Once someone speaks, the original and the translation appear side by side here.

Reading subtitles while you watch

Subtitles are hidden when you switch tabs. Press “Show in a floating window” and a small window stays in front, so you can read subtitles with the video full screen. You can move and resize it.

Keeping the subtitles

Press “Download transcript” to save the original and the translation with timestamps as a text file. Useful for reviewing later.

Choosing what you watch

“What are you watching?” in step 1 sets how speech is recognised. Each option suits different material. If you are unsure, leave it as it is, on the live stream option.

What you watchChooseWhat happens
Live streams, broadcasts, newsWatching a live streamSubtitles keep up. Best for continuous speech.
Recordings, lectures, saved videoWatching a recordingPlace names and people's names come out right, but subtitles take a little longer.
When your computer is slowMy computer is slowUses the least power, with more mishearing.

Choosing the recording option for a live stream can make subtitles fall behind. A message appears when that happens; follow it and switch back.

Switching downloads the data for that option, about 238MB for the recording option. Subtitles keep running on the previous option while it downloads, so nothing stops. You can switch as often as you like, at no extra cost.

When names come out differently each time

Speech recognition turns unfamiliar names into similar-sounding words. Add the correct spelling to the word list in step 3, one per line, and it will be corrected. Add each form you expect, such as both “Fable” and “Fable 5.1”.

If something is not working

It says no audio was shared
Step 4 was missed. Start again and tick the box at the bottom left of the dialog.
The green bar moves but no subtitles appear
The audio is arriving. It is waiting for a pause. A sentence appears after a short silence, or after about 8 seconds at most.
The green bar never moves
You may have shared the wrong tab, or the video may be muted. Check the video's volume too.
Only the original appears, with no translation
Translation uses Chrome's built-in feature. When it is unavailable, only the original is shown. If step 4 shows a message, press “Check translation again”, because the first check can time out while the feature is still preparing. If nothing changes, update to the latest Chrome on desktop.
It stopped part way through
Press Stop, then press Start again.