slidecap 0.4.0

CLI tool to generate slide-aligned markdown notes from YouTube videos or local video files.

slidecap

CLI tool that turns a YouTube video into slide-aligned markdown notes for agent/LLM workflows.

What It Does

1. Downloads a YouTube video at 1080p (strict by default).
2. Detects slide changes using SSIM-based frame comparison (same behavior as your existing app).
3. Transcribes audio with Whisper.
4. Aligns transcript chunks to detected slide timestamps.
5. Writes:
   • A markdown file with slide sections + transcript text.
   • Slide images to one shared images folder.

Install

pip install slidecap

System dependencies:

• ffmpeg in PATH
• yt-dlp in PATH

Usage

Minimal — just pass a URL:

slidecap --url "https://www.youtube.com/watch?v=abc123"

This creates:

./slidecap/
  My Video Title.md
  slides/
    yt_abc123_slide_001_t000005.jpg
    ...

Custom output paths:

slidecap \
  --url "https://www.youtube.com/watch?v=abc123" \
  --out-md "/path/to/vault/notes/abc123.md" \
  --images-dir "/path/to/vault/assets/youtube-slides"

JSON output (for agents):

slidecap --url "https://www.youtube.com/watch?v=abc123" --json

Flags

• --url (required): YouTube URL.
• --out-md (optional): Output markdown path. Defaults to ./slidecap/<video title>.md.
• --images-dir (optional): Slide images folder. Defaults to ./slidecap/slides/.
• --similarity-threshold (default 0.85): Slide detection threshold.
• --sample-rate (default 1.0): Frame sampling interval in seconds.
• --whisper-model (default medium): Whisper model name. See Whisper Models below.
• --language: Optional transcription language code (e.g. en, de, ja).
• --image-format (default jpg): jpg or png.
• --image-quality (default 90): JPEG quality.
• --allow-lower-quality: Fallback below 1080p if exact 1080p is unavailable.
• --overwrite: Overwrite existing markdown output.
• --keep-temp: Keep temp downloads for debugging.
• --log-level (default info): debug|info|warn|error.
• --json: Print structured JSON result (success or error) for agent workflows.

Whisper Models

Model	Speed	Accuracy	Notes
tiny	Fastest	Lowest	Quick drafts
base	Fast	Good
small	Moderate	Better	Good general choice
medium	Slow	Strong	Default
large	Slowest	Best	Alias for latest large
large-v1	Slowest	Best	Original large
large-v2	Slowest	Best	Improved large
large-v3	Slowest	Best	Latest multilingual
large-v3-turbo	Fast	Very good	Distilled large-v3
turbo	Fast	Very good	Alias for large-v3-turbo

English-only variants (tiny.en, base.en, small.en, medium.en) are faster than their multilingual counterparts when transcribing English content.

Output Format

The markdown file includes:

• source metadata
• table of contents
• per-slide sections with:
  • timestamped YouTube link
  • relative markdown image link
  • transcript chunk aligned to that slide

Images are named to avoid collisions:

• yt_<video-id>_slide_<nnn>_t<seconds>.<ext>

JSON Response Shape

Success:

{
  "status": "ok",
  "url": "https://www.youtube.com/watch?v=abc123",
  "video_id": "abc123",
  "output_markdown": "/path/to/vault/notes/abc123.md",
  "images_dir": "/path/to/vault/assets/youtube-slides",
  "slide_count": 12,
  "image_files": [],
  "downloaded_resolution": "1920x1080",
  "downloaded_fps": "30",
  "format_note": "1080p",
  "download_format": "bestvideo[height=1080]+bestaudio/best[height=1080]",
  "similarity_threshold": 0.85,
  "sample_rate": 1.0,
  "whisper_model": "medium",
  "language": "en",
  "started_at": "2026-02-23T00:00:00+00:00",
  "completed_at": "2026-02-23T00:03:00+00:00",
  "duration_seconds": 180.123,
  "warnings": []
}

Error:

{
  "status": "error",
  "error": "message",
  "error_type": "RuntimeError"
}