About

What MakeSubtitles is and how it works.

What is MakeSubtitles?

MakeSubtitles is a free web tool that extracts subtitles from video or audio files and translates them with AI, saved as SRT files. It's built for people who watch foreign-language videos, create language-learning material, or want subtitles for their personal video collection — without installing any software.

Traditionally, making subtitles meant installing speech-recognition software, setting up a GPU environment, and copy-pasting the results into a translator. MakeSubtitles aims to compress that entire workflow into a single page and a single button.

How does it work?

The most important design principle is: your files are never uploaded to a server. The pipeline looks like this:

• Step 1 — Audio extraction: your video never leaves your device. The browser separates the audio track locally, using FFmpeg compiled to WebAssembly.
• Step 2 — Subtitle extraction: the audio is transcribed by Whisper large-v3-turbo, a state-of-the-art speech recognition model, producing timestamped subtitles.
• Step 3 — Hallucination filter: fake lines that speech models invent during silence ("Thanks for watching" and the like) and abnormal repetitions are removed automatically.
• Step 4 — AI translation: Claude AI translates the subtitles while considering the surrounding dialogue. You can pin down speech styles (tone) and terminology (glossary).
• Step 5 — SRT download: you get both the original and the translated subtitles as SRT files.

Why do I enter my own API keys?

MakeSubtitles has no server. Your browser calls the speech-recognition service (Groq) and the translation service (Anthropic) directly, so you bring your own API keys. This design has two advantages:

• Transparency: it's clear where your data goes. Audio goes to Groq, subtitle text goes to Anthropic — nothing passes through any middleman server.
• Cost control: you pay only for what you use, on your own accounts. Processing an hour-long video typically costs a few cents.

Your API keys are stored only in your browser's local storage and are never transmitted anywhere else.

What's next

We plan to keep adding tools that subtitle work actually needs — subtitle timing adjustment, format conversion (SRT ↔ VTT ↔ LRC), and proofreading helpers.

Contact

Found a problem or have a feature request? Email us at [email protected].