SRT
The universal one. Every player and platform reads it, and it carries text and timings โ but no styling at all.
Export
Take the subtitles with you, styling included
A subtitle file that loses its design is just a transcript with timecodes. Pick the format that keeps what you built.
Open the editor โFive ways out
VTT
The web format. Built for HTML5 video, so it is what you want when the player lives on your own page.
ASS
The one that keeps the design: fonts, colours, outlines, positions and animations survive the export.
MP4 / MOV
Burned in. The captions become part of the picture, so nothing can strip or restyle them.
Which one you actually want
Uploading to a platform that renders captions itself โ YouTube, a course player, a CMS? Send SRT or VTT and let the player draw them. The text stays selectable and searchable, and viewers can turn it off.
Built a look worth keeping โ a font, a highlight colour, words landing one at a time? Export ASS, or burn it into MP4. A styled design pushed through SRT arrives as plain white text on black, and the work is gone.
Posting to feeds where captions are the whole point and autoplay is silent? Burn them in. Vertical platforms strip sidecar files, and a burned-in video looks the same everywhere.
File or burned in
A sidecar file travels next to the video and is drawn by the player. It stays editable, it can be swapped for another language, and viewers can switch it off โ but you are at the mercy of whatever the player decides captions should look like.
Burning in renders the captions into the frames. The design is guaranteed, at the cost of being permanent: changing a typo means rendering again.
Video export runs as a chain โ the renderer builds the picture, then the export step packages it. That is why an MP4 takes longer than an SRT, and why the SRT is ready the moment you stop editing.
When subtitles do not show up
The file is next to the video but nothing appears. Most players match a sidecar file by name, so ยซclip.mp4ยป wants ยซclip.srtยป in the same folder โ a mismatch is the single most common reason captions stay invisible.
The text arrives as question marks or gibberish. That is an encoding problem: subtitle files should be UTF-8, and anything written in an older single-byte encoding will break the moment it meets Cyrillic. Our exports are UTF-8 throughout.
The styling is gone. Check the extension before blaming the player: SRT and VTT have no way to store a font, a colour or a position, so a design pushed through them arrives as the player's default. If the look matters, export ASS or burn it in.
The timings drift. This happens when subtitles built against one cut are attached to another โ a re-edit, a trimmed intro, a different frame rate. Re-export from the project rather than shifting the file by hand.
The platform ignores the upload entirely. Vertical feeds mostly do not accept sidecar files at all; there the burned-in MP4 is not a preference but the only option that works.
Common handoffs
Upload to YouTube
SRT alongside the video: searchable captions and a transcript the platform can index.
Your own site
VTT with an HTML5 player keeps captions accessible and selectable.
Short vertical video
Burned-in MP4, because feeds autoplay muted and drop sidecar files.
Handing off to an editor
ASS carries the design into Premiere, DaVinci or Aegisub without a rebuild.
Looking for the words rather than the subtitles? The transcriber exports plain text, Markdown and JSON as well. Go to transcription โ
FAQ
ASS, or a burned-in MP4 or MOV. SRT and VTT carry text and timings only โ any font, colour or animation is dropped, because the format has nowhere to put it.
Beautiful captions.
Better videos.
Captions Space generates AI subtitles, styles them with designer presets and exports the finished video.
Start for free โNo credit card required
- โ Free plan available
- โ One-click instant export
- โ Built for creators
Runs in the browser โ no install, no credit card, and a free plan with 2 videos a month.