Free private local video subtitle translator
Drop a video file and walk away with bilingual SRT subtitles — transcribed and translated entirely in your browser.
Drop an MP4, WebM, or MOV video here
or click to choose files from your device
Up to 200 MB · Demuxed in browser memory · Local Whisper, never uploaded
The default: multilingual, accurate enough for real use, and small enough to download once without thinking about it.
Free to use · No account · No video upload · Offline after model download
What is a video subtitle translator?
A video subtitle translator extracts spoken dialogue from a video container, aligns the speech with accurate timecodes, and translates the resulting transcript into target languages. Unlike cloud services that require uploading gigabytes of footage, LangsAny processes the entire pipeline on your personal device.
Your browser demuxes the container, pulls out the audio stream, runs Whisper speech recognition, and produces standard subtitle files ready to mount in VLC or upload to video hosting platforms. Read more in how browser speech recognition works.
How to translate video subtitles in three steps
No video compression, no command-line tools, and no external audio extractors.
- 01
Drop your video container
Drag in an MP4 or WebM video. The browser accesses the file through the File API and demuxes the audio track into memory without touching the video stream.
- 02
Transcribe with on-device Whisper
Whisper performs speech-to-text inference on your GPU or CPU via WebGPU, aligning every spoken phrase with millisecond-accurate start and end timestamps.
- 03
Translate and download SRT
Translate the transcript into your chosen language in a single pass. Download clean SRT or WebVTT subtitle files with bilingual or monolingual cues.
Straight out of the container with zero command line
The traditional workflow for subtitling a foreign video is tedious: configure ffmpeg on the command line to strip the audio track, upload the sound file to a paid transcription service, await email notification, manually correct drift, and finally merge the SRT file back.
This video subtitle translator eliminates every external step. Your web browser already contains production decoders for MP4 and WebM. LangsAny feeds the decoded audio track directly into Whisper, producing synchronized subtitles in minutes.
00:01:14,320 --> 00:01:16,900
Bienvenidos a la segunda clase.
Welcome to the second class.
Why standalone subtitle files beat burned-in video
Burning subtitles permanently into video frames requires decoding every single frame, rasterizing typography, and re-encoding video streams. Inside a web browser, re-encoding a 1080p feature film takes hours and rapidly exhausts CPU thermal budgets.
- Bilingual cues for language learners
- Generating an SRT file allows both original audio transcription and translated text to be presented concurrently within the same cue. Language students can read original dialogue and target meanings without permanently obscuring background visuals.
- Universal compatibility across all media players
- Standard subtitle files (.srt and .vtt) work in VLC, mpv, IINA, QuickTime, YouTube, and editing suites. Toggle subtitles on or off, adjust font sizing, and customize line spacing to suit any viewing environment.
- Confidentiality for unreleased footage
- Unreleased footage, legal depositions, user interviews, and internal company meetings are files creators cannot entrust to public web services. Keeping all transcription within the client tab ensures data never leaves your device.
Subtitle video files by spoken language
Whisper is trained across 99+ world languages. Browse dedicated language pages to review vocabulary tuning and subtitle alignment nuances.
Your video stays on your device
Every step — demuxing, transcription, translation — runs inside your browser tab. Video bytes are never read into network buffers, and no audio leaves the page. The subtitle files you download are the only output.
Read more about the privacy architecture in why private translation matters.
What to know before you start
- Browser codec support
- Only containers your browser can decode natively — MP4, WebM, and most MOV files. If a container uses an exotic audio codec, the page alerts you immediately rather than producing empty subtitles.
- Subtitles are not burned in
- Output is a standalone SRT or WebVTT file. Re-encoding video frames inside a browser is impractical, so the original video file is never modified.
- Speech model download
- The Whisper model (~40 MB) downloads once on first use and is cached for subsequent runs. A stable connection is needed for that initial fetch.
- Accuracy depends on audio quality
- Background noise, overlapping speakers, and heavy accents reduce transcription accuracy. Always proofread the output before publishing or sharing.
- This is a draft, not a certified translation
- Subtitles are AI-generated and not reviewed by a human translator. Check names, numbers, and specialist terms against the original audio.
Video subtitle translation FAQ
Practical answers about container decoding, timestamps, and bilingual subtitle exports.
What is a video subtitle translator?
A video subtitle translator is a tool that extracts spoken dialogue from a video container, aligns the speech with accurate timecodes, and translates the resulting transcript into target languages. LangsAny runs this entire pipeline on your personal device — your browser demuxes the container, transcribes speech with Whisper, and produces standard SRT or WebVTT subtitle files.
Do I need to extract the audio track first?
No. Modern web browsers already contain native demuxers and decoders for MP4 (AAC) and WebM (Opus/Vorbis). LangsAny reads the audio track directly from the video container in memory, eliminating separate ffmpeg commands or desktop utility software.
Does it burn subtitles into the video frames?
No, deliberately. Burning subtitles into video pixels requires full video re-encoding, which takes considerable time and drains laptop batteries in a web browser. Instead, you download standard SRT or WebVTT files that open in VLC, mpv, IINA, YouTube, or Premiere, keeping typography sharp, editable, and optional.
How do I load the generated SRT file into my video player?
Save the downloaded subtitle file in the same directory as your video with an identical base name (for instance, movie.mp4 and movie.srt). Popular players like VLC and mpv load the subtitle track automatically upon playback. You can also drag and drop the subtitle file onto the playing video window.
Which video container formats are supported?
Any container your browser can decode natively: MP4, WebM, and most MOV files. If a container contains an exotic audio codec that the browser cannot decode, the page alerts you immediately rather than generating an empty subtitle track.
Is my video footage kept private and confidential?
Completely. Video files remain strictly on your local disk. Only the audio track is streamed into the browser tab's audio buffer for the duration of transcription. Unreleased documentaries, internal corporate all-hands, and private family videos never travel across the internet.
For a deeper look at how in-browser speech recognition works, read the full technical walkthrough.
Translate video subtitles with this free browser tool
Drop an MP4, WebM, or MOV file above, generate timed subtitles with on-device Whisper, and export clean bilingual SRT files with zero cloud uploads.