# Video Transcript Explainer > Extract or reuse video transcripts for Bilibili/YouTube, then generate high-quality Chinese lecture handouts (LaTeX + PDF) that are self-contained, coverage-complete, and length-adaptive to video duration and content density. Use when users want to learn the full video from notes alone. - **Type:** Skill - **Install:** `agentstack add skill-crysgate-agentskills-video-transcript-explainer` - **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior - **Seller:** [CrysGate](https://agentstack.voostack.com/s/crysgate) - **Installs:** 0 - **Category:** [Content & Media](https://agentstack.voostack.com/c/content-and-media) - **Latest version:** 0.1.0 - **License:** MIT - **Upstream author:** [CrysGate](https://github.com/CrysGate) - **Source:** https://github.com/CrysGate/AgentSkills/tree/main/video-transcript-explainer ## Install ```sh agentstack add skill-crysgate-agentskills-video-transcript-explainer ``` Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent. ## About # Video Transcript Explainer ## Goal Produce a high-quality Chinese lecture handout (`notes-body.tex` -> `notes.tex` -> `notes.pdf`) that is complete enough for a diligent reader to master the video without watching it. The handout must: - scale in length with video duration and content density - proactively teach prerequisite knowledge that the speaker assumes - preserve the full reasoning chain (not only conclusions) - cover late-video sections with the same rigor as early sections ## When To Use - The user wants subtitle extraction + deep Chinese lecture notes + PDF. - The user expects a targeted, teachable handout, not a brief summary. - The user wants adaptive page count (different videos should produce different lengths). ## Procedure 1. Transcript first (do not change acquisition logic) - Use `VIDEO_ROOT=~/Desktop/bilibili-video`. - Keep output under `"$VIDEO_ROOT/output"`. - Reuse an existing `transcript.txt` for the same video unless the user explicitly asks for `--refresh`. - Run: `UV_CACHE_DIR="$VIDEO_ROOT/.uv-cache" uv run --with yt-dlp --with mlx-whisper python ~/.codex/skills/video-transcript-explainer/scripts/video_transcript.py ""` - This step is network-dependent; prefer escalated execution in sandboxed environments. - Add `--cookies /path/to/cookies.txt` only for gated videos. - Add `--save-cookies-from-browser chrome` once if the user wants reusable Bilibili login cookies. - Add `--refresh` only when explicitly requested. 2. Keep transcript artifacts in one place - Keep all transcript outputs under `~/Desktop/bilibili-video/output`. - Do not write transcript artifacts outside that folder. 3. Enter the video output directory and inspect inputs - Read `transcript.txt` first. - Read `metadata.json` when present. - Typical downstream artifacts: - `notes-body.tex` - `note-title.txt` - `notes.tex` - `notes.pdf` 4. Build a coverage plan before drafting - Identify major topic segments from the transcript. - For each segment, record internally: - What question this segment answers - Which details are easy to miss - What prerequisite knowledge a reader might lack - Ensure the plan includes the entire video timeline, including the final third. 5. Decide autonomously whether to use subagents - Never use subagents for transcript extraction itself. - Subagents are optional acceleration, not mandatory. - If runtime/policy blocks subagents, continue locally without blocking. - Heuristics that favor subagents: - more than 6000 Chinese characters - more than 120 timestamped blocks - multiple dense topic shifts - high formula/code/comparison density - If using subagents, split work into 2-4 coherent chunks (time ranges or topic bundles). - Assign each subagent a concrete task package and require outputs for: - segment intent and teaching objective - corrected key statements (ASR repairs) - LaTeX-ready `\section` / `\subsection` draft - formulas, code, examples, pitfalls worth emphasizing - prerequisite assumptions that need bridging - ambiguities requiring main-agent arbitration - The main agent must unify terminology, resolve contradictions, normalize structure, and produce one consistent `notes-body.tex`. 6. Draft as a standalone teachable handout (not a thin summary) - Replace spoken fillers with clear teaching prose. - Preserve nontrivial details, comparisons, caveats, and speaker intent. - Fix obvious ASR errors by context. - Add prerequisite bridges where needed so the text is self-contained. - Prefer expansion over compression when completeness is at risk. - Do not use vague placeholders such as "not elaborated here". - Default teaching shape per major topic: - one-sentence overview - detailed explanation - logical step-by-step flow - plain-language interpretation of key concepts - for technical/math content: intuition + example + input/output relationship 7. Enforce adaptive note length - Never default to a fixed page target. - Estimate expected depth from: - `metadata.json` duration (if available) - transcript character count - timestamped block count - number of topic shifts - density of formulas/code/comparisons/caveats - Planning heuristic (not a hard quota): - `10-20 min`: usually `5-9` pages - `20-35 min`: usually `8-14` pages - `35-50 min`: usually `12-20` pages - `50-70 min`: usually `16-28` pages - `70+ min`: usually `22-40+` pages - Dense technical lectures should land in the upper half or exceed the range. - If a 60-minute technical video produces roughly the same length as a 20-minute one, treat it as over-compressed and expand before shipping. 8. Minimum depth standard per major topic - Unless clearly irrelevant, cover: - what it is - why it matters - what problem it solves - how it connects to previous/next topics - inputs/outputs or participating entities - step-by-step mechanism - why this approach vs alternatives - at least one intuition, analogy, or concrete scenario - common pitfalls, boundary conditions, failure modes - If a technical topic states conclusions without reasoning, that section is incomplete. 9. Clean the title before rendering - Inspect raw video title. - If noisy/duplicated/SEO-heavy/too long, write a polished short title to `/note-title.txt`. - Prefer clean forms like: - `Course Name Lecture X: Topic` - `Course Name: Topic` - `Topic Deep Dive` - Remove marketing noise and repetitive tags. 10. Render with the existing template pipeline - Write `/notes-body.tex` first. - Run: `python ~/.codex/skills/video-transcript-explainer/scripts/render_notes_pdf.py --transcript "" --metadata "/metadata.json" --body "/notes-body.tex" --output-dir ""` - The renderer prefers `note-title.txt` when present. - After rendering, sanity-check PDF page count when tooling allows; otherwise use `notes-body.tex` size as a proxy. - If output is materially shorter than the coverage plan for that video's duration/density, expand and rerender. 11. `notes-body.tex` writing rules - Use `\section{...}` and `\subsection{...}`. - Prefer teaching order over strict transcript order. - Every major section must contain substantive explanation. - Define specialized terms in Chinese on first use. - Use `importantbox`, `knowledgebox`, `warningbox` only when they add value. - Formula rule: - explain intuitively in Chinese first - show `$$...$$` - define symbols - explain sensitivity: what changes when key variables change - Code rule: - use `lstlisting` with a short caption - explain problem, inputs/outputs, and design rationale - Preserve explicit comparisons and trade-offs when the speaker compares approaches. - Add prerequisite bridge subsections whenever a careful reader could get stuck. - For long/dense videos, substantially longer notes are expected and desirable. - End with a final summary section (use a Chinese heading equivalent to "Summary" in the generated notes). - Do not append recommendation sections unless explicitly requested. 12. Quality gate before final render - Read `notes-body.tex` once as a student who did not watch the video. - Expand before shipping if any answer is "no": - Can I reconstruct the full lecture storyline, not just isolated conclusions? - Are first-time technical terms understandable at first mention? - Does each formula include intuition, symbol definitions, and practical use? - Does each code block explain what problem it solves? - Are important late-video topics covered with equal depth? - Is reasoning explained, not merely summarized? - Is the handout length aligned with duration, topic count, and technical density? - For longer videos, is there clearly more substantive explanation instead of template reuse? - Could a diligent reader learn the full lesson from this PDF alone? - If the last answer is not a confident "yes", keep expanding. 13. Delivery - Return a concise Chinese summary to the user. - Point to: - `transcript.txt` - `notes.tex` - `notes.pdf` - If TeX compilation fails, report the error clearly and keep generated `.tex` artifacts. ## Source & license This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code. - **Author:** [CrysGate](https://github.com/CrysGate) - **Source:** [CrysGate/AgentSkills](https://github.com/CrysGate/AgentSkills) - **License:** MIT Install and usage instructions live in the source repository linked above. ## Pricing - **Free** — Free ## Security capabilities Automated source analysis of v0.1.0 — what this tool can access: - **Network access:** no - **Filesystem access:** no - **Shell / process execution:** no - **Environment & secrets:** no - **Dynamic code execution:** no *"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.* ## Versions - **0.1.0** — security scan: passed — Imported from the upstream source. ## Links - Listing page: https://agentstack.voostack.com/l/skill-crysgate-agentskills-video-transcript-explainer - Seller: https://agentstack.voostack.com/s/crysgate - Browse the marketplace: https://agentstack.voostack.com/browse --- Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.