MP4 to SRT

What you get

An SRT is a plain text file of numbered cues, each with a start time, an end time and the words. Players, YouTube, Vimeo, LinkedIn and editors read it. It sits beside your MP4 as a "soft" subtitle track, which viewers can turn off. This is different from burned-in (open) captions, which are part of the picture; we do not render those, so for burned-in captions import the SRT into a video editor.

Steps

1. Choose the MP4 above (extract the audio first with the video to audio tool if it is a big file).
2. Check the transcript against the video; subtitle timing follows the transcript segments.
3. Export SRT from the editor's Export menu.
4. Upload the .srt wherever your video is published. Each platform's subtitle upload menu has its own wording; check its help page.

Tidy the cues

Each cue is one transcript segment as the recogniser produced it. Segments sometimes run longer than the two lines of about 42 characters that most subtitle guidance suggests. Fix that in the browser, with nothing uploaded, using the subtitle line splitter. If your whole file is a few seconds early or late, the subtitle time shifter moves every cue at once.

SRT or VTT?

Use SRT unless a platform asks for WebVTT. VTT is the web standard with a few extra features. Both are exported from the same transcript; see file formats explained and audio to VTT.