How do I add subtitles to a video?
How to add subtitles to a video depends on which of two very different jobs you mean. If you already have a subtitle file, you only need to attach it. If you do not, you first have to turn the speech into text. Knowing which job you are in tells you how long it will take and which tool you need.
Two jobs: you have subtitles, or you do not
- Job A — you have an .srt, .vtt or .ass file: attach it to the video or load it in the player.
- Job B — no subtitle file exists: you must transcribe the audio first, then optionally translate it.
If you already have a subtitle file
For a file you keep locally, most players load a subtitle next to the video automatically if the names match — for example movie.mp4 and movie.srt. For a permanent burn-in or a hard attachment, use ffmpeg:
For an online upload such as your own YouTube video, use the Subtitles section in YouTube Studio and upload the file as a new track. The platform handles timing as long as the timestamps are correct.
If you have no subtitle file, generate them from the audio
With no file to attach, the subtitles have to be created from the audio. This is exactly what the WatchTranslate local player does: open it, drop the video in, choose your target language, and click Start translation, then press play. Subtitles are generated and translated while the video runs, in around 30-second chunks, so you do not upload the whole file and a large video will not stall.
The same engine powers the browser extension for web video: on YouTube or X it reads the audio (or an existing track) and shows translated subtitles on the page.
Translating subtitles into another language
If you have a subtitle file or an embedded track in a language you do not read, it still needs translating. A file-based workflow means exporting the text, translating it and re-timing it; the in-player route translates as it plays and lets you switch between the original, the translation, or both at once.
What it does and doesn't do
- Supported hosts: YouTube / X / Bilibili / Pornhub / MissAV (ordinary videos only); no live streams.
- Generates subtitles from audio when no subtitle file exists
- Translates existing subtitles directly
- Failed runs do not consume credits
- Supported embedded text tracks can be translated directly; image subtitles need audio recognition.
- No live streams
FAQ
How do I add subtitles to a video with no subtitle file?
Generate them from the audio. The local player (for files) or the browser extension (for web video) transcribes the speech and translates it while you watch — no .srt required.
Can I add subtitles without editing software?
Yes. If you only need to watch with subtitles, a player that generates and translates them on the fly is enough. Editing software is only needed if you want to burn subtitles permanently into the file.
Is the video uploaded when subtitles are generated?
Not as a whole file. Audio is read in roughly 30-second chunks; the original video stays on your machine or on the platform.
Which languages are supported?
Subtitles are available in 74 languages, including English, 中文, 日本語, 한국어, Español, Français, Deutsch, Português, Русский, العربية and हिन्दी. The source language is detected automatically.