How it works

Three steps.
No learning curve.

Drop your video in, pick a style, export. OpaCaptions does the hard parts for you: it listens, writes down every word with its timing and puts the captions on your video, all on your own PC. No editing skills, no tutorials, nothing to set up first.

Interface preview: OpaCaptions is in early access. A 30-second clip takes about 10 seconds on an ordinary laptop in Fast mode.

Who does what

You do three things.
OpaCaptions does the rest.

If you can choose a filter, you can do this.

You

  1. Drop your video inDrag it onto the window, or click Open.
  2. Pick a styleHover over any style and it plays on your video before you choose.
  3. ExportOne click saves the captioned video, ready to post.

Optional: click any word to fix it. Typing the right word is all it takes.

OpaCaptions, automatically

  • Recognises the language and writes down every word
  • Times each word to the moment it's spoken
  • Breaks the words into easy-to-read caption lines
  • Places the captions clear of the app buttons on vertical videos
  • Tells speakers apart and labels them (Pro)
  • Styles and animates the captions, then saves your video, subtitles and transcript

Each step in detail

Curious what's happening?
Here's every step.

  1. 1

    Drop in a file

    Drag any video or audio file into the window: MP4, MOV, MKV, WEBM, MP3, WAV or M4A, of any size, up to 4 hours long. Vertical, landscape and audio-only all work.

    The file is read straight from your drive. Nothing is copied anywhere else.

  2. 2

    Transcribe

    OpenAI's open-source Whisper model listens and writes down every word with its exact timing. Pick Fast, Balanced or Best accuracy, and the spoken language, or let it detect the language for you.

    Whisper runs on your own processor. No graphics card, no cloud.

  3. 3

    Style

    Choose a caption style and see it on your video straight away; on Pro, tweak its font, colours, size and position. One switch turns any of the 17 languages into English captions.

    The preview is live; nothing is rendered until you export.

  4. 4

    Review

    Read the transcript beside the video. Every word lights up as it's spoken, search finds any moment, and a click on any misheard word lets you fix it, on every plan.

    Your transcript stays a file on your PC, not a record on someone's server.

  5. 5

    Export

    Get an MP4 with the captions burned in, ready for TikTok, Reels and Shorts, plus SRT and VTT subtitle files and a TXT transcript, saved to your folder.

    Rendering uses ffmpeg on your PC. Upload counter: still 0 bytes.

Requirements

Nothing to set up first.
Your PC probably has what it needs.

Install it, open it, drop in a video. The Fast speech model comes with the app, so your first video doesn't wait for a download.

Windows 10 or 1164-bit. A Mac version is on the roadmap.
8 GB of RAMAn ordinary laptop is enough.
No graphics cardEverything runs on the processor.
About 150 MB to 1.6 GBFor the speech model, downloaded once, depending on the accuracy you use.
Internet, barelyTo download the model, activate your licence and check for updates. Captioning itself works offline.

Speed and accuracy

Fast when you need it.
Careful when it counts.

On the 8th-generation Intel Core i5 laptop we build on, a 24-second clip is captioned and rendered in about 9 seconds in Fast mode. Faster PCs simply finish sooner.

ModeBest forModel download
FastClear speech, quick social clipsabout 150 MB
BalancedMost videos and podcastsabout 0.5 GB
BestAccents, background noise and technical wordsabout 1.6 GB

Balanced and Best take longer than Fast, in exchange for catching more words in difficult audio.

Works offline

Switch on airplane mode.
It keeps working.

After the one-time model download and licence activation, OpaCaptions needs no internet at all. That's the simplest proof that your footage never leaves your PC: unplug the network and caption a video. Read more in our privacy policy, or see what stays on your PC.

Your first captioned video
is three steps away.

Start freeSee pricing