Upload a video and CaptionX auto-generates the captions and hardcodes them permanently into the frames. Download a captioned MP4 that displays everywhere — no subtitle file needed.
Drag & drop your video
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Video · under 2 GB · stays on your device · no sign-up to start
Drop in an MP4, MOV or WebM. It stays on your device — no sign-up needed to start.
CaptionX transcribes the audio, times the captions, and lets you pick a style and fix any line.
Export and the captions are burned permanently into the frames — download a captioned MP4 ready to post.
A separate subtitle file (SRT/VTT) can be turned off, ignored, or lost. Burning captions in — hardcoding them — makes them part of the video itself, so every viewer sees them, everywhere.
85% of social video is watched on mute. Burned-in captions display on every feed — Instagram, TikTok, LinkedIn — with no subtitle file to lose.
Hardcoded captions can't be turned off, stripped, or fall out of sync. What you export is exactly what every viewer sees.
Skip the SRT step entirely — CaptionX generates the captions for you, then burns them in. One upload, one download.
Caption and burn in the language your audience actually speaks, with automatic transcription.
Burning subtitles (also called hardcoding, or open captions) means writing the caption text permanently into the video's pixels, rather than keeping it in a separate subtitle file. Once burned in, the captions always display — on every platform and device, even ones that don't support subtitle files.
No. CaptionX generates the captions from your video's audio automatically, then burns them in — you don't need an existing subtitle file. Just upload your video, review the captions, and export. If you do want a separate file too, you can also download a clean SRT.
Upload your video above. CaptionX transcribes the audio, places timed captions on it, and — when you export — hardcodes them into the frames as an MP4. Exporting is free (free exports carry a small CaptionX watermark; Pro removes it).
No — and that is the point. Hardcoded subtitles are permanent, so they show on Instagram, TikTok, LinkedIn, and anywhere else that ignores separate subtitle files or plays muted by default. If you need toggle-able captions instead, export an SRT and upload it alongside your video.
A standard MP4 with the captions burned into every frame — ready to post anywhere. No re-encoding in a separate editor, no compositing a subtitle track yourself.
The burn-in runs in your browser — CaptionX renders the captioned MP4 on your device, so the video file itself isn't uploaded. To generate the captions, the audio is sent securely to CaptionX's transcription service, then the timed captions come back and are burned in locally. No sign-up required to start.
The full browser studio — auto-caption, style, edit and export a captioned MP4.
Already have an SRT? Render it into a subtitle overlay MP4.
Generate a clean SRT from any audio or video, no watermark.
Prefer to caption inside Adobe Premiere Pro? Use the CaptionX extension.