Captions vs subtitles
In everyday use the words overlap, but there is a real difference. Subtitles assume the viewer can hear and only need the dialogue, often translated. Captions (closed captions) are written for viewers who cannot hear the audio, so they also describe meaningful sounds like [door slams] or [upbeat music] and identify off-screen speakers. The US FCC caption quality rules and the BBC Subtitle Guidelines both ask for that sound information. SubtitleWave writes the speech; add sound tags in square brackets by editing a line.
Open vs closed captions
- Closed captions are a separate text track (an SRT or VTT file) that viewers switch on or off. YouTube, Vimeo and LinkedIn support them, and search engines can read them.
- Open captions are burned into the picture. They show everywhere, including autoplaying feeds that many people scroll with the sound off, and on apps that ignore caption files, such as TikTok and Instagram Reels.
This caption generator does both from the same transcript: switch to the Export tab and choose a file or “Render captioned video”.
Choosing a caption style
| Look | Use it for |
|---|---|
| Broadcast box | Interviews, tutorials, anything with busy backgrounds; white on a black box is the most legible option and the classic TV caption look. |
| Outline | Cinematic footage where a box would block too much of the frame. |
| Bold + word highlight | Shorts, Reels and TikTok: 2 to 3 words at a time, uppercase, the spoken word lit up. |
| Soft shadow | Calm, minimal edits over darker footage. |
Keep captions in the lower third, but raise them (the “Vertical position” slider) on vertical video so they clear the app's own buttons and description text.
Questions people ask
How do I auto-generate captions for a video?
Drop the video above, press “Generate subtitles”, correct any wrong words in the Edit tab, pick a look in the Style tab, and use Export to render a captioned video or download an SRT file.
Are the captions added as a watermark-free MP4?
Yes. The captioned video is rendered in your browser without any watermark. Chrome, Edge and Safari produce MP4; Firefox produces WebM, which YouTube and most editors accept.
Can I edit the auto captions?
Every caption line is editable: text, start and end time, split, merge and delete. Changes show on the video preview instantly.
Do captions help with SEO?
A closed caption file on YouTube gives the platform an accurate transcript to index, which is better than its own automatic captions. Burned-in captions are not readable by search engines, so for YouTube upload the SRT as well.