Open Captions: Always-On Captions for Any Screen

Open and closed, briefly

Closed captions live in a separate track and appear only when a viewer, or the person running the screen, turns them on. Open captions are drawn into the image, so they can't be turned off and need no support from the player. Technically, open captions are made the same way as burned-in subtitles; what makes them captions is the content. They are written for people who can't hear the audio, so besides dialogue they identify who is speaking when that isn't obvious and describe sounds that matter, such as laughter, a door slamming or music starting. The history and trade-offs are laid out in open versus closed captions.

Where open captions earn their place

• Captioned screenings. Cinemas, community film nights and festivals run open-caption sessions so deaf and hard-of-hearing audiences can attend any show without special equipment.
• Conferences and town halls. Talk replays on a venue screen or an all-hands stream recording reach the back row and the people standing by the door.
• Waiting rooms, lobbies and retail screens. These usually play with the sound off or drowned out, so captions carry the entire message.
• Kiosks and museum loops. Visitors arrive mid-video, and the loop can't wait for anyone to find a menu.
• Classrooms. Projected video is easier to follow with words on screen, especially for students working in a second language.
• Social feeds. Many people scroll with the sound muted, and feed players rarely show closed caption tracks from your file.

Captions need more than the words

AI subtitles transcribe speech, and only speech. They don't label speakers or describe sounds, so an open-caption version needs a short manual pass after the draft. Common conventions:

• Put sound descriptions in square brackets: [applause], [phone ringing], [music fades].
• Name a speaker who is off screen or hard to identify at the start of their line, for example "NURSE:" or "(Host)".
• Mark song lyrics or background music so viewers know why nobody is speaking.
• Keep descriptions short and only include sounds that change what the viewer understands.

The editor makes these additions quick: pause where the sound happens, press Enter to add a line at the playhead and type the cue. If a line runs across two speakers, Split it at the playhead and label each half. For the full style of captions written for deaf and hard-of-hearing viewers, see SDH subtitles and captioning sound effects and music.

Preparing open captions for a screening or event

1. Load the locked final cut, not a draft. Captions timed to an earlier edit will drift wherever scenes were trimmed.
2. Get the dialogue in. Run AI subtitles (the spoken language is detected automatically) or use Import SRT / VTT for a file from your captioner.
3. Read every line against the audio, then add the speaker labels and sound cues described above.
4. Open the Style tab and pick something built for distance, such as High Contrast or Classic. Raise the size until the preview reads comfortably from your seat; size is relative to the video's shorter side, so it scales with any resolution.
5. Keep captions at the bottom unless graphics, slides or name titles live there, in which case move them to the top or add a vertical offset.
6. Render video, download the MP4, and play it on the actual screen or player at the venue before the day.

Reading from the back of a room

A caption that is fine on a laptop can fail on a projector. Contrast suffers most: washed-out projection and bright scenes swallow thin white text, so a solid or translucent box behind the words usually beats an outline alone. Length is next. The editor warns when a line passes 42 characters and wraps it, but for a big room shorter lines are kinder, because eyes have further to travel across the screen. Reading speed matters for the same reason; heed the warning when a line runs faster than about 21 characters per second, and merge or reword rather than letting it flash past.

Loops add one more consideration. A waiting-room or kiosk video has no soundtrack in practice, so the captions are the only channel. Spell out on-screen speakers, read out key numbers, and make sure the last caption doesn't sit over the first frame when the video restarts. Subtitle readability goes deeper into line length and timing.

Policies, requests and what to check

Organisations sometimes ask for open captions in their accessibility policy, a venue booking or a grant agreement. This page can't tell you whether a particular rule is met, so confirm with whoever made the request whether open captions satisfy it, and whether they also want a transcript or a closed-caption file for the online version. The editor can give you all three from one session: the captioned MP4, plus Export SRT or Export VTT for players that support tracks, and the video to text tool for a plain transcript. The video accessibility checklist is a useful prompt for the rest.

If you only need caption files and no rendered video, the subtitle generator is the shorter route.

Three open-caption jobs

About the subtitle editor on this page

Opens

MP4, MOV, M4V, WebM, MKV videos your browser can decode

Subtitles from

AI (from the speech, optionally translated into one of 21 languages), an SRT or VTT file, or typing them in

You download

An MP4 with the subtitles drawn into the picture at the original resolution and frame rate, plus SRT and VTT files

Cost

Editing, styling, rendering and SRT/VTT export are free, with no account and no watermark. AI subtitles cost 1 credit per minute (5-credit minimum per video); signing in with Google gives 100 free credits and accounts get 10 free credits a day

Privacy

The video never leaves your device and is rendered in your browser. Only for AI subtitles is the audio sent, over HTTPS, and it is deleted within 30 minutes of delivery

Rendering needs

Chrome or Edge 94+, Safari 16.4+, or Firefox 130+ on a computer. Editing and SRT/VTT export work in any current browser