LiveSub
Translate a Japanese livestream in real time (free, in your browser)
Published: 2026-09-15 ・ Updated: 2026-11-03
Works in Chrome or Edge on a computer (Firefox: through a microphone or audio input; the add-on covers YouTube and Twitch; not on phones). Japanese ⇄ English only.
A lot of good Japanese content only happens live: game streams, news broadcasts streamed on video sites, talk shows, late-night radio-style streams, VTubers.
While it is live, there are usually no English subtitles. Translated clips may come later, but only for the parts someone chose to clip.
This guide shows how to get live English subtitles on any Japanese stream playing in a browser tab, for free, without installing anything.
What you'll learn
- How to put live English subtitles on any Japanese stream in your browser
- Which recognition setting to choose for Japanese
- Which kinds of streams work well, and which do not
In short: add the free LiveSub extension for Chrome or Edge on your computer, press its icon on the stream's tab, and set “Translate from / to” to Japanese → English in the LiveSub tab that opens. English subtitles appear over the video about one to two seconds behind the speaker, for as long as the stream runs, with no sharing dialog. Without the extension, open LiveSub in another tab and share the stream's tab instead.
What you need and how it works
- Chrome or Microsoft Edge on a computer. In Firefox, LiveSub listens through a microphone or a loopback audio input (such as Windows Stereo Mix); on YouTube and Twitch, LiveSub for Firefox turns the video's audio into subtitles directly. Safari uses the same input method but is untested
- Not a phone or tablet. Mobile browsers cannot share tab audio
- A one-time download of the speech recognition model. For Japanese, the recommended setting is about 670MB; after the first time it is loaded from your browser's storage
No account, no extension, no payment.
Using Firefox? Firefox cannot share a tab's audio, so LiveSub listens through a microphone or an audio input instead. Open LiveSub in Firefox, play the video in another tab, and press "Start (mic or audio input)" on the LiveSub page. Allow microphone access when the browser asks. If your computer has a loopback input (such as Windows Stereo Mix), LiveSub picks it automatically; otherwise it listens through the microphone to the sound from your speakers (headphones will not work). There is no sharing dialog. On YouTube and Twitch, LiveSub for Firefox turns the video's audio into subtitles directly: press "Add to Firefox — it's free" to install it, play the video in another tab, and press "Start (YouTube / Twitch tab)"; the subtitles appear over the video.
LiveSub is a website. You share one browser tab's audio with it, and it:
- recognises the Japanese speech on your own computer (the model runs inside the browser),
- translates it with Chrome's built-in on-device translator,
- shows the Japanese and the English as subtitles.
Your audio is not uploaded anywhere. Because nothing runs on a server, there is no per-minute limit, and there is no list of supported sites. If it plays sound in a tab, it can be subtitled.
Step by step
- Open the stream in Chrome
- In another tab, open LiveSub
- Under "Translate from / to", choose Japanese → English. The app uses a different recognition model for Japanese, so if you leave it on English → Japanese, you will get garbled text instead of subtitles
- Under "Recognition setting", leave it on Balanced for now (see below)
- Press "Try the how-to video (no sharing)" once. It plays a short how-to video in Japanese and shows subtitles without sharing any tab, and it gets the one-time download out of the way
- Click "Start (share a tab)"
- In Chrome's dialog, pick the "Chrome Tab" section, choose the tab playing the stream, and tick "Also share tab audio" at the bottom left. Then click Share
Play the stream. Subtitles appear about one to two seconds after the words are spoken. On the first run, they start once the model has finished loading.
If nothing appears, it is almost always the audio checkbox in step 7. Press "Share again" and tick it.
Choosing a recognition setting
| Setting | When to use it |
|---|---|
| Balanced | The recommended starting point |
| Lighter | If subtitles fall behind. It mishears a little more |
| Lightest | For older computers. It mishears Japanese a lot |
A few things to know:
- If your computer cannot keep up, the app tells you and moves to a lighter setting
- You can switch settings while the stream is running. Subtitles keep coming from the current model while the new one downloads
What works well, and what does not
- News and commentary. One clear speaker at a time is the best case
- Talk shows and chatting streams. Work well, but accuracy drops when several people talk over each other
- Game streams. Loud music and sound effects reduce accuracy. If you are also playing a game on the same computer and it starts stuttering, tick "Don't use the GPU"
- VTuber streams. They work the same way; there is a separate guide on watching Japanese VTuber streams with English subtitles, including tips for names
- Singing streams. Music makes recognition unreliable. Do not expect much here
Making it comfortable to watch
Floating window
Click "Show in a floating window". The subtitles move into a small window that stays on top, so you can watch the stream in fullscreen and still read them. You can move and resize it, and scroll back to earlier lines.
Display mode
Choose "Original and translation", "Translation only" or "Original only". If you are learning Japanese, seeing both is useful.
Word list
Recognition often gets names wrong: people, places, game titles, show segments. Add the correct spellings to the word list, one per line (Japanese entries need at least 3 characters), and they will be corrected automatically. To choose how a name appears in the translation too, write it as "たなか = Tanaka".
Transcript download
"Download transcript" saves the Japanese and the English with timestamps as a text file.
Announcement streams and voice actor talk shows work the same way. The guide to anime event streams covers what is different about them.
Honest limits
- About one to two seconds of delay. This is not simultaneous interpretation
- It is machine translation. You get the gist; jokes, wordplay and nuance often do not survive
- Names are the weak point. The word list helps, but it does not catch everything
- Only the audio is translated. Chat and text on screen are not
- Computer only. It needs Chrome or Edge on a desktop or laptop (Firefox: through a microphone or audio input)
Wrapping up
If a Japanese stream plays in a browser tab, LiveSub can subtitle it in English while it is live, with no per-minute limit and no list of supported sites.
Open the Japanese stream you have been meaning to watch, then open LiveSub on your computer and press "Try the how-to video (no sharing)" first.
About this guide: written by the maker of LiveSub. Steps, button names and figures are checked against the LiveSub app as of the date above. If something is wrong, please tell us through the contact page.