ai-subtitle-extractor

Extract existing captions from online videos and restructure them into translated articles.

6|Updated Jul 6, 2026
One-click install
npx skills add https://github.com/Guojiz/ai-subtitle-extractor --skill ai-subtitle-extractor-guojiz
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: ai-subtitle-extractor
Source: https://github.com/Guojiz/ai-subtitle-extractor
Command: npx skills add https://github.com/Guojiz/ai-subtitle-extractor --skill ai-subtitle-extractor-guojiz

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires agent-browser, and includes scripts (resource) components.

What problem does it solve? Turning an online video link into a clean, readable transcript usually means downloading the video or running speech recognition. This Skill reads the subtitle tracks the platform already serves (YouTube, Bilibili, or generic sites), prefers human tracks over auto-generated ones, removes speech noise, and delivers a complete article in the user's language. ## Core Features & Use Cases - Platform-agnostic pipeline: Verified adapters for YouTube (timedtext capture, transcript panel) and Bilibili (view/dm-view APIs), plus generic discovery via network sniffing, textTracks, and <track> tags for any other site. - Multiple access backends: Pure HTTP/CLI, agent-browser page injection, Tampermonkey userscript, or WebBridge evaluate against the user's logged-in browser, with lawful-use confirmation before full export. - Editorial delivery contract: Captures all timed cues with coverage verification, removes filler words and false starts while preserving every substantive claim, then restructures and fully translates into the user's language before summaries or Q&A. - Use Case: A user pastes a Bilibili or YouTube link and asks for the content as an article; the agent confirms lawful use, pulls the complete human subtitle track, verifies cue coverage, and returns a polished translated article. ## Quick Start Give the agent a video link and ask it to extract the subtitles and deliver a complete article in your language, confirming lawful use when prompted.

Frequently Asked Questions about ai-subtitle-extractor

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I extract subtitles from a YouTube or Bilibili video without downloading it?

Provide the video URL and confirm lawful use; the pipeline reads the platform's existing caption tracks via Bilibili's view/dm-view APIs or YouTube's timedtext responses. Human tracks are preferred over auto-generated ones, and no video download or ASR is involved.

What tools can extract captions from any video website?

This recipe uses generic discovery for unknown sites: hooking fetch/XHR for subtitle requests, reading HTML5 textTracks and <track> tags, and parsing transcript panel DOM. It runs through agent-browser injection, a Tampermonkey userscript, or WebBridge evaluate.

Why does fetching YouTube captionTracks baseUrl return an empty body?

A direct baseUrl fetch often returns HTTP 200 with an empty body because session parameters are incomplete; this does not mean the video lacks captions. The fix is to enable CC and capture the player's own timedtext network request instead.

Why does Bilibili subtitle download fail in a browser but work with curl?

Two browser-specific issues cause this: http:// subtitle URLs are blocked as mixed content on HTTPS pages, and the CDN's Access-Control-Allow-Origin: * rejects requests carrying cookies. Upgrade the URL to https:// and fetch with credentials set to omit.

What happens when a video has no captions at all?

The pipeline honestly reports that no captions were found after trying all discovery channels and browser fallbacks. ASR is only considered as a last resort after that, and unverified sites are never claimed as supported.