# Lecture > Extract transcript and key slides from a local video file, then create a vault-formatted lecture note. Use this skill whenever a user provides a local video file (.mp4, .mov, .mkv, .avi, .webm) and wants notes from it. Triggers on "lecture", "take notes", "I have a recording of", "class video", "transcribe this presentation", "process this video for notes", or /lecture. Works with any language — auto-detects transcript language. - Skill: `tuan3w/lecture` (Agent Skill, multi-file: 3 files) - Install (CLI): `npx skillmds@latest add tuan3w/lecture` - Raw SKILL.md: https://api.skillmd.com/api/skills/tuan3w/lecture/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Docs & Writing - Author: tuan3w (https://skillmd.com/u/tuan3w) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tuan3w/lecture --- Transcribe a local video lecture using mlx-whisper (Apple Silicon), extract key slide frames with timestamps, then synthesize into a vault-formatted lecture note with embedded screenshots. Auto-detects transcript language — works with any language, outputs English notes. - User provides a local video file and wants lecture notes - User says "take notes from this lecture/video" - User uses /lecture with a file path - User has an MP4/MOV/MKV file to process - User has a YouTube URL (use /youtube instead) - User wants to process an existing vault note (use /process) - User wants audio-only transcription without note synthesis - `ffmpeg` installed (for audio extraction and frame capture) - `uv` installed (`brew install uv` or `curl -LsSf https://astral.sh/uv/install.sh | sh`) - Apple Silicon Mac (mlx-whisper is optimized for M-series chips) - Extract first, synthesize second, integrate third - Always check vault for existing notes on the same topic before creating - Create note as type: lecture with processing_status: inbox - The note is a starting point — user can /process it later for deeper engagement - Transcription can take several minutes for long videos — inform the user ## Stage 1: EXTRACT Parse the video file path from $ARGUMENTS. If no path provided, ask the user. Verify the file exists and is a video format (mp4, mov, mkv, avi, webm). Run the extraction script: ```bash SKILL_DIR="${CLAUDE_SKILL_DIR}" LECTURE_OUTPUT="temp/lecture-extract-output.json" uv run "$SKILL_DIR/scripts/extract_lecture.py" "VIDEO_PATH" > "$LECTURE_OUTPUT" 2>&1 & ``` **IMPORTANT:** This script takes time (several minutes for a 30-60 min video). Inform the user: "Extracting audio and transcribing — this will take a few minutes for a [duration] video." Run it and wait for completion. Then read the output JSON. The JSON contains: - `filename`, `duration`, `duration_seconds`, `width`, `height` - `transcript.full_text`, `transcript.segments` (with start/end times), `transcript.language` - `transcript.error` (null if success) - `frames[]` — array of `{path, timestamp_seconds, timestamp}` for each extracted slide - `output_dir` — temp directory with extracted frames **If transcript.error is not null:** inform the user and stop. Check if mlx-whisper is installed. **If transcript is very long (>80,000 chars):** warn the user. Send first 60,000 chars to the agent with a note about total length. ## Stage 2: PREPARE FRAMES Copy the extracted frames to the vault's assets directory with a descriptive naming scheme: ```bash # Generate a slug from the video filename SLUG=$(echo "VIDEO_FILENAME" | sed 's/\.[^.]*$//' | tr '[:upper:]' '[:lower:]' | tr ' ' '-' | sed 's/[^a-z0-9-]//g' | cut -c1-30) ASSETS_DIR="assets" for frame in FRAME_PATHS; do FRAME_NUM=$(basename "$frame" | grep -o '[0-9]*') cp "$frame" "$ASSETS_DIR/lecture-${SLUG}-${FRAME_NUM}.jpg" done ``` Build a frame manifest for the noter agent — each frame gets: - Its vault filename (for `![[embedding]]`) - Its timestamp in the video (e.g., "12:30") Example manifest: ``` FRAMES WITH TIMESTAMPS: - lecture-risk-mgmt-01.jpg (timestamp: 0:10) - lecture-risk-mgmt-02.jpg (timestamp: 2:00) - lecture-risk-mgmt-03.jpg (timestamp: 4:00) ... ``` ## Stage 3: SYNTHESIZE Read the agent definition: ``` Read("${CLAUDE_SKILL_DIR}/agents/lecture-noter.md") ``` Search the vault for existing notes related to the lecture's topics using the MCP tool: ``` search_notes(query="KEYWORD", limit=20) ``` Or fall back to Grep if MCP is unavailable: ``` Grep(pattern="KEYWORD", path="notes/", glob="*.md", head_limit=20) ``` **Review each frame** using the Read tool to see what's on each slide. Build a brief description of each frame's content (1 line each) to include in the agent prompt. Launch the lecture-noter agent: ``` Agent( subagent_type="general-purpose", model="sonnet", run_in_background=false, prompt="You are Lecture Noter. Follow these instructions exactly: [INSERT FULL CONTENT OF agents/lecture-noter.md HERE] VIDEO METADATA: - Filename: [filename] - Duration: [duration] - Transcript language: [language from extraction JSON] FRAMES WITH TIMESTAMPS AND DESCRIPTIONS: - lecture-slug-01.jpg (timestamp: 0:10) — Title slide showing course name - lecture-slug-02.jpg (timestamp: 2:00) — Diagram of risk framework [... one line per frame with what you see on it] EXISTING VAULT NOTES ON RELATED TOPICS: [List any matching notes found in grep search] TRANSCRIPT: [full_text] Produce the note body following the Output Format. Do NOT include frontmatter — only the body starting from the # title line. Use the exact filenames from FRAMES list for ![[embedding]] — do not invent filenames." ) ``` ## Stage 4: INTEGRATE 1. Generate timestamp ID: ```bash date +%Y%m%d%H%M%S ``` 2. Determine the best subfolder for the note: - ML/AI → `notes/ml/` - Business/startup → `notes/startup/` - Finance → `notes/finance/` - Design → `notes/design/` - Psychology → `notes/psychology/` - General → `notes/` 3. Create the note file with frontmatter + agent output: ```markdown --- id: YYYYMMDDHHMMSS type: lecture processing_status: inbox created_date: YYYY-MM-DD updated_date: YYYY-MM-DD --- [AGENT OUTPUT HERE — starts with # title, includes embedded screenshots] ``` 4. Clean up temp files: ```bash rm -rf "$OUTPUT_DIR" rm -f "$LECTURE_OUTPUT" ``` 5. Report to user: - Note path and title - Number of screenshots embedded - Number of concepts suggested for extraction - Any related vault notes found - Remind: "Run /process on this note when you're ready to deepen it" - **Bash**: Run extract_lecture.py, copy frames, generate timestamps, search vault - **Read**: Read agent definition, read extracted JSON, view frame images for descriptions, read existing vault notes - **Write**: Create the lecture note in vault - **Agent**: Delegate synthesis to lecture-noter agent (sonnet model) - **Grep/Glob**: Search vault for duplicates and related notes User: /lecture /tmp/risk-management-training.mp4 1. Extract → transcript (48 min video, ~59K chars Vietnamese) + 12 frames with timestamps 2. Copy frames to assets/ as lecture-risk-mgmt-01.jpg through lecture-risk-mgmt-08.jpg 3. Review each frame → build descriptions (title slide, framework diagram, severity table, etc.) 4. Search vault → found 3 related notes on risk and finance topics 5. Agent synthesizes → 6 themed sections, 5 embedded screenshots, 4 questions, 3 concept suggestions 6. Create note → notes/finance/(Lecture) Risk Management Overview.md 7. Report: "Created lecture note with 6 sections and 5 embedded slides. Found connections to [[(Term) Credit Cycle]] and [[(Term) Second-Order Thinking]]. 3 concepts could become Term notes. Run /process when ready." User: /lecture /tmp/risk-management-training.mp4 - Dumps raw transcript into a note without synthesis - Saves screenshots without timestamps, can't trace back to video - Creates chronological summary instead of thematic organization - Misses cross-domain connections - Doesn't review frame content before passing to agent - **uv not installed**: Print install command (`brew install uv`) and stop - **ffmpeg not found**: Inform user to install via homebrew - **Transcript error**: Report the error, suggest checking audio track - **Video extremely long (>3hrs)**: Warn user, offer to process first half only - **No audio track**: Inform user, offer to extract frames only - **Duplicate note exists**: Show existing note, ask if user wants to update or create new $ARGUMENTS