Guide
Karaoke style captions, and when they work on podcast clips
By Rakshit · Updated
Karaoke style captions show a line of text and highlight each word at the moment it is spoken, like lyrics on a karaoke screen. They tend to suit fast, punchy podcast clips and dense sentences least. In KeyMo, the Karaoke, Spotlight and Slide styles do this; KeyMo has no free plan.
What the effect is
The name comes from lyric videos. A short group of words sits on screen, and as the speaker reaches each word it changes: a colour, a size, a bar underneath. The highlight marks where the speaker is in the line. Everything visible is already there; only the highlight moves.
That is different from captions where words pop in one by one, which the word-by-word captions guide covers. Here the line is stable and the emphasis travels along it.
How the timing works
A highlight can only be as good as the timing under it. Each word needs a start and end time from the transcript. The same idea exists in caption files: the WebVTT specification allows timestamps inside a cue's text that mark when a point in the cue becomes active, as long as each is later than the cue start, earlier than the cue end and later than any earlier timestamp in the same cue. W3C also notes that some players use caption files to build interactive transcripts that highlight phrases as they are spoken.
For a clip with burned-in captions, the tool does this work and draws the result. If a word is late or early the effect looks sloppy, which is why a quick check of the first and last lines of each clip is worth the minute.
KeyMo styles that highlight the spoken word
KeyMo has 12 caption styles plus no captions: Pro Glow, Bold Pop, Clean, Punch, Classic, Spotlight, Pulse, Karaoke, Reader, Duo, Slide and Headline. Three of them are built around a travelling highlight.
| Style | What happens to the spoken word | Our suggestion |
|---|---|---|
| Karaoke | Heavy rounded type, two lines. The word being spoken turns green and grows slightly, then goes back to white as the next one lights | Short, energetic lines and strong opinions |
| Spotlight | Every word is visible. The spoken word is picked out in mint while the rest stay grey | Longer lines where you want the full sentence readable |
| Slide | Stacked lines of mixed sizes. A coloured bar slides under each word as it is spoken, and the active word grows a little | Clips where one or two key words carry the point |
Reader works on a related idea on a light box: words darken as they are spoken. All of them are word-by-word, because KeyMo times captions to each word.
When karaoke captions help, and when they do not
- Use them on fast, punchy speech: a host making a point in a few short lines.
- Use them when you want a designed look rather than plain text.
- Skip them for dense, technical sentences. Highlight styles hold a whole group of words on screen, and W3C's guidance puts captions at one or two lines, generally under 32 characters per line. That is a common practice, not a rule, but a long sentence with a flashing word is hard to read.
- Skip them in cross-talk. If two people overlap, the highlight jumps and the clip gets noisy.
- Check contrast. WCAG's general minimum for text is a contrast ratio of 4.5:1 (3:1 for large text). It sets no caption-specific ratio, and the highlight colour should still stand out from the base colour and from the footage behind it.
How to get them on every clip
- Import the episode. Paste a YouTube link (paid plans) or upload an MP4 or MOV of 5 minutes to 3 hours.
- Pick a clip length: Auto 15 to 90 seconds, Short 20 to 40, Medium 40 to 60 or Long 60 to 90.
- Let KeyMo pick and score the moments. Only clips scoring 7 or higher out of 10 are kept, so you may get fewer than the 15 maximum.
- Choose Karaoke, Spotlight or Slide as the caption style, preview, and export. Clips are 9:16 at 1080x1920 with no watermark.
If a word is wrong or a style feels too loud for a calm interview, open the clip in the chat editor and tell KeyMo what to change. The podcast to Reels page shows the same flow for Instagram.
Sources: W3C: WebVTT, The Web Video Text Tracks Format (checked 11 October 2026); W3C WAI: Captions/Subtitles (checked 11 October 2026); W3C WAI: Transcribing Audio to Text (checked 11 October 2026); W3C: Web Content Accessibility Guidelines (WCAG) 2.2 (checked 11 October 2026).