Hey Product Hunt!

We're excited to launch our latest free tool: AI Caption Generator by VdoCipher.

Why we built this

At VdoCipher, we've spent 10+ years building video infrastructure, helping thousands of platforms securely host, protect, and deliver video content.

One recurring frustration we've noticed among course creators, educators, marketers, and video teams is how expensive and inconvenient automatic caption generation can be.

You have a recorded lecture, a podcast, an interview, or a marketing video. You just want accurate subtitles.

But many online caption generators require you to upload your video to their servers, create an account, and pay based on the number of minutes you transcribe.

And if you're working with unreleased courses, internal recordings, confidential interviews, or private videos, uploading your content to an unfamiliar server isn't always an option.

Even after paying, you may still need another tool to edit subtitle timings, export an SRT file, or permanently add captions to your video.

So we built something different.

A completely free AI caption generator that runs locally in your browser using OpenAI's Whisper speech recognition model.

No video uploads, no subscriptions, no per-minute charges, and no watermark.

Here's what it can do:

AI-powered captions: Automatically generate subtitles from video and audio using Whisper AI, with word-level timestamps.
99 languages: Transcribe speech in around 99 languages, including English, Hindi, Spanish, French, German, Arabic, and more.
Three AI models: Choose Fast for quick drafts, Balanced for everyday use, or Accurate for challenging audio.
Translate to English: Generate English captions from speech in other supported languages.
Built-in subtitle editor: Review and correct transcribed words before downloading.
Multiple export formats: Download subtitles in SRT, VTT, or plain text.
Batch caption generation: Process multiple video or audio files in one session.
Burn subtitles into videos: Permanently add captions to the video itself and export a ready-to-share MP4.
Private by design: All transcription, editing, and video processing happen locally using WebAssembly and WebGPU where supported.

And there's one important difference from most AI caption generators:

Your video and audio never leave your device.

Whisper runs directly in your browser rather than sending your content to a cloud transcription API.

The AI model downloads the first time you use it and is cached locally for subsequent sessions.

So you're not paying by the minute or waiting for your video to upload before transcription can begin.

Who it's for

Course creators adding subtitles to educational videos, YouTubers captioning their content, podcasters creating transcripts, marketers preparing videos for social media, journalists transcribing interviews, and anyone who wants accessible video content without paying for another subscription.

It's also useful for teams handling sensitive recordings that they don't want to upload to third-party AI services.

Try it for free (no signup needed):

https://www.vdocipher.com/tools/caption-generator/