Closed Caption Generator for SRT and VTT Files

Closed, open and who controls them

The closed in closed captions means hidden until asked for. The captions travel as a separate track, usually an SRT or VTT file uploaded alongside the video, and each viewer decides whether to show them. Open captions are the opposite: drawn into the picture, always visible, identical wherever the video plays.

Closed captions

A file or track. Viewers switch them on or off, you can replace the file without touching the video, and the player decides how they look. They only work where the player or platform accepts caption files.

Open captions

Part of the video frames. Always on, styled exactly as you designed, and they survive messaging apps and re-uploads. Correcting them means rendering again.

Captions, as opposed to subtitles, are written for people who can't hear the audio, so they carry more than dialogue: who is speaking when it isn't obvious, and sounds that matter. Captions vs subtitles and open vs closed captions sort out the terminology.

Producing a closed-caption file

1. Open the editor and choose the video. Keep "Write the subtitles automatically with AI" ticked, with Subtitle language on "Same as spoken (auto-detect)" so the captions match the audio.
2. Sign in with Google when prompted. Only the audio is uploaded for transcription; the picture stays in your browser.
3. Play the video through and correct every wrong word, name and number in the line list.
4. Add the speaker labels and sound cues the AI leaves out, as described in the next section.
5. Clear the warnings: overlaps, lines too fast to read, and lines over 42 characters.
6. Click Export SRT or Export VTT, depending on where the file is going.

You don't need to render a video for closed captions at all. The exported file is the deliverable.

Adding what the AI leaves out

The AI writes only words it hears spoken. It doesn't say who is talking, and it doesn't describe music, laughter, a slammed door or a ringing phone. For a proper closed-caption file, that information goes in by hand.

• Speaker labels. Type the name at the start of the line when the speaker is off screen or changes mid-scene, for example "MAYA: We start at nine." Keep labels short, since they count towards the line length.
• Two speakers in one caption. Put the playhead where the second voice starts and press Split, then label each half. Alternatively, give each speaker their own row inside one caption, each row starting with a hyphen.
• Sound cues. Pause where the sound happens, press Enter to add a line at the playhead, and type the description in square brackets: [door slams], [phone buzzing], [crowd cheering]. Drag its end on the timeline so it covers the sound.
• Music. A short cue such as [tense music] when the music carries meaning, and the sung words themselves when lyrics matter to the scene.
• Manner. A cue like [whispering] or [sarcastic] when the words alone would mislead.

Where a sound happens during speech, avoid overlapping captions, which some players display poorly. End the speech line before the cue begins, or add the cue as its own row inside the speech caption. Conventions vary between broadcasters and platforms; captioning sound effects and music gathers the common ones, and SDH subtitles applies them step by step.

SRT or VTT?

Both formats hold the same timed text. What differs is where each is accepted.

SRT

The most widely accepted caption file. YouTube, Vimeo, Facebook, LinkedIn and most desktop editors take it. Plain text with numbered cues.

VTT (WebVTT)

The format browsers use for the HTML5 track element, so it's the one for a player on your own website. YouTube and Vimeo accept it too.

Either export contains exactly the text and timings you see in the editor. The finer differences are in SRT vs VTT.

Uploading closed captions

Each platform hides caption upload in a slightly different place, but the steps rhyme: open the video's settings, find captions or subtitles, choose the language and upload the file.

• YouTube: in YouTube Studio, open the video, go to Subtitles, add the language and upload the file with timing. Uploading SRT to YouTube walks through it.
• Vimeo: see adding subtitles to Vimeo.
• Your own site: reference a VTT from a track element, as shown in HTML5 video subtitles.
• Facebook: upload the SRT in the video's caption settings; the file name often needs a language code, explained in adding SRT to Facebook video.

Name the file clearly before you upload it, especially if you keep versions in several languages; subtitle file naming suggests a pattern.

When closed captions won't be seen

A closed-caption file only works where the player supports it. Videos forwarded on WhatsApp, posted as Stories or Reels, or played on screens in a venue usually ignore caption files entirely. For those, render the same lines into the picture as open captions: open Style, pick a readable preset, click Render video and download the MP4. One session then gives you both deliverables. The open captions page covers that route.

Formats this doesn't produce

Television and some streaming services ask for broadcast caption formats such as SCC, embedded CEA-608 or 708 data, or a platform-specific XML file. The editor exports SRT and VTT only, and it doesn't write a caption track inside the MP4. If a distributor asks for those formats, convert the SRT with professional captioning software or hand it to a captioning vendor; CEA-608 vs 708 explains what they are. To add the SRT as a switchable track inside an MKV or MP4, a muxing tool such as FFmpeg or MKVToolNix does the job. And if all you need is a plain SRT from speech with no cues added, the SRT generator is the shorter path.

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