Subtitle Conversion FAQ
7 common questions about converting and re-syncing subtitles in your browser.
Frequently asked questions (7)
How do I convert SRT to VTT?
Drop your .srt file on the drop zone (or paste its text), then click the "WebVTT" target button. The converter reads the SRT comma-millisecond timecodes, adds the WEBVTT header at the top, and rewrites each timestamp with a dot separator. Preview the result, then copy it or download a .vtt file. Every step runs inside your browser.
Are my subtitle files uploaded anywhere?
No. subconvert reads and converts files entirely inside your browser. Nothing is sent to a server, there is no account, and no copy of your subtitles is ever stored online. Only your conversion settings (target format and offset) are kept in localStorage, and the shareable ?s= link carries those settings, never the file content.
My subtitles are out of sync — can I fix the timing?
Yes. Enter a value in seconds in the sync offset field and every cue shifts at once. A positive value delays the subtitles; a negative value moves them earlier. For example, enter -1.5 if the subtitles appear 1.5 seconds too late. The ±0.5s and ±1s quick buttons help you fine-tune, and the offset is baked into the output you copy or download.
My Korean subtitles show broken characters. What can I do?
Older Korean SMI and SRT files are often saved in EUC-KR instead of UTF-8, so they look garbled when read as UTF-8. Switch the encoding selector to EUC-KR and the same file is re-decoded correctly. Output is always UTF-8, so a single conversion turns the broken file into a clean subtitle that displays properly in modern players and browsers.
What is the SMI (SAMI) format?
SMI (SAMI) is a Microsoft subtitle format that was the de-facto standard on older Korean media players for years. Each caption is a SYNC tag holding a start time in milliseconds followed by a P paragraph, and an empty nbsp cue clears the screen. subconvert reads this structure into timed cues and converts to SRT or VTT, and back again.
What does converting to TXT produce?
TXT output strips every timecode and joins the caption text in order as a plain transcript. It is handy for proofreading subtitles, drafting a translation, or quoting lines in a blog post. Because it has no timing, TXT cannot be converted back into a timed format such as SRT, VTT or SMI afterwards.
When should I use FPS retiming?
Use it when subtitles start in sync but drift further apart the longer the video plays. That is caused by a frame-rate mismatch between the video the subtitles were made for and your copy. Pick the source and target FPS (e.g. 23.976 to 25) in the advanced options to rescale the whole timeline. If the file is simply shifted by a constant amount, use the sync offset instead.