Captions
Written for viewers who cannot hear the audio, in the same language as the video. They can show who is speaking alongside sound cues like [applause] or [door closes].
Captions and subtitles
How captions differ from subtitles.
If a viewer cannot hear a video, captions give them the spoken words and often the sound effects as text.
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If they can hear the video but do not speak the language, subtitles translate the dialogue for them. You can generate both from a single timed transcript.
- Captionsspoken words and sounds written out
- Subtitlesspoken words translated into another language
- Open or closedburned into the video or kept as a separate file
- SRT · VTTthe file formats usually used for both
The differences in three lines
People mix the terms up in everyday conversation, and in the UK and much of Europe, both are called subtitles. Accessibility guidelines and many video platforms separate them like this.
Subtitles
Written for viewers who hear the audio just fine but do not know the language. They usually only translate the spoken dialogue into the viewer's language.
SDH
Short for subtitles for the deaf and hard of hearing. They put the dialogue and the sound cues together on a regular subtitle track.
Open versus closed
You can deliver either type of text to the viewer in two ways.
Closed: a separate file
You keep the text in a standalone file like an SRT or VTT, which video platforms usually let you upload. Viewers can toggle it on or off and sometimes pick a language.
Open: burned into the picture
You bake the words right into the video frames so they stay on screen and cannot be turned off. That works well for muted feeds or video players that lack a subtitle menu.
Which to choose
Upload closed files whenever the platform supports them. If the video will play without viewer controls, like in a social feed, burn the text into the picture.
Making both from a single transcript
Transcribe the video once
Upload your video to get a timed transcript with speaker labels.
Build the captions
Check the text, type in the sound cues you want viewers to read, and export an SRT or VTT file in the spoken language.
Build the subtitles
Translate that transcript into another supported language and export a second file. Ask someone who knows the language to read through it before you publish.
Burn them in when needed
If you are posting somewhere without a subtitle menu, burn the captions or subtitles directly into the video. Hebrew and Arabic text is laid out from right to left.
For developers and AI agents
You can also run everything KolWrite does with a recording through our API. Send the address of an audio or video file from your own code or an AI coding agent, and you'll get back the transcript with word timings, speaker labels, and an SRT file if you request one.
Word timings and speakers
The JSON output gives you the start and end time for every segment, plus individual word timings on models that support alignment. Turn on speaker separation to include a speaker label on each segment.
SRT and translation
Pass output_format as srt if you want subtitles directly from the API. If you are using the Oracle models, you can also set translate_to to get the text back in another language.
Built for agents
The API console publishes plain-text instructions for an agent to read before writing code. This includes agent-instructions.md, along with llms.txt, which links to the full reference.
Questions
What is the difference between captions and subtitles?
Captions are for people who cannot hear the audio; they keep the original language and often add sound cues. Subtitles are for people who hear the audio but do not speak the language, so they translate the dialogue. In some regions, people call both of them subtitles.
Are closed captions the same as an SRT file?
SRT is one common file format used to deliver closed captions. "Closed" means the viewer can turn the text on and off, while SRT (or VTT) is the file format that carries that text.
What are open captions?
Open captions are baked directly into the video frames. Because they are no longer a separate file and viewers cannot switch them off, make sure you proofread the text before burning it in.
Do I need captions or subtitles for social video?
Many people watch on mute, so having words on the picture helps during the first few seconds. Upload an SRT if the platform accepts one, or use burned-in captions on platforms without a subtitle menu. Check the current rules for each platform.
Can I add captions in Hebrew or Arabic?
Yes. You can transcribe Hebrew or Arabic audio and either export an SRT or burn the text into the video. Both languages run right to left, so watch the finished video before publishing to check the punctuation and any mixed-in English words.
Can an automatic transcript meet accessibility rules?
Not on its own. Accessibility standards require captions to be accurate, complete, and properly timed. Somebody still needs to read through the transcript, add sound cues, and check the sync before it goes live.
Try captioning one video to see how both work.
Take one transcript, export it as captions, translate it into subtitles, and test both tracks in your video player.