Reference

summarize slides

GitHub Edit page

summarize slides

summarize slides <source> [flags]

Extracts slide-shaped keyframes from a YouTube URL, direct video URL, or local video file using FFmpeg scene detection. Native ffmpeg is preferred; bundled FFmpeg WebAssembly is used when native ffmpeg/ffprobe are unavailable. Output is a directory of PNGs (and optional OCR text). This is the standalone form of the --slides flag on the main command — useful when you only want the slides without a summary.

#Synopsis

summarize slides "https://youtu.be/..."
summarize slides "https://youtu.be/..." --render auto
summarize slides "https://youtu.be/..." --slides-ocr -o ./out
summarize slides "https://example.com/lecture.mp4" --slides-max 12
summarize slides ./lecture.mp4 --slides-max 12

#Requirements

  • Bundled FFmpeg WebAssembly, or native ffmpeg on PATH for faster extraction and broader codec support.
  • yt-dlp on PATH for YouTube URLs.
  • tesseract on PATH for --slides-ocr.

If a required tool is missing, summarize prints a clear warning and exits non-zero.

#Flags

--slides-ocr : Run OCR on every extracted slide. Stores ocrText and ocrConfidence in slides.json and the JSON response.

--slides-dir <dir> : Output base directory. Default: ./slides. A per-video subfolder is created inside.

-o, --output <dir> : Alias for --slides-dir.

--slides-scene-threshold <value> : Scene detection threshold, 0.1–1.0. Default 0.3. Lower values detect more scenes (more slides); higher values are stricter.

--slides-max <count> : Cap on extracted slides. Default 6.

--slides-min-duration <seconds> : Minimum gap between slides. Default 2.

--render <mode> : Inline render of thumbnails: auto, kitty, iterm, none. Default none — paths are printed instead.

--theme <name> : Pick a CLI theme.

--timeout <duration> : Per-operation timeout setting. Default 2m; not an overall wall-clock deadline. yt-dlp downloads and FFmpeg scene detection allow at least 5m, and individual extraction/probe steps have their own limits.

--no-cache : Force re-download and re-extraction (bypasses both caches).

--json : JSON envelope on stdout. Disables inline rendering.

--verbose / --debug : Detailed progress on stderr.

-V, --version : Print version and exit.

#Output

Each run writes a directory like:

slides/<source-id>/
  slide_0001_18.60s.png
  slide_0002_42.20s.png
  ...
  slides.json

The filenames include the slide index and timestamp. slides.json records the manifest, including OCR results when requested; OCR does not create separate text files. ocrConfidence uses a 0–1 scale.

In --json mode, stdout contains an envelope like this (additional extraction metadata omitted):

{
  "ok": true,
  "slides": {
    "sourceUrl": "https://example.com/lecture.mp4",
    "slidesDir": "/absolute/path/slides/<id>",
    "slides": [
      {
        "index": 1,
        "timestamp": 18.6,
        "imagePath": "/absolute/path/slides/<id>/slide_0001_18.60s.png",
        "ocrText": "Recognized slide text",
        "ocrConfidence": 0.92
      }
    ]
  }
}

#Inline rendering

--render auto detects Kitty (KITTY_WINDOW_ID) and iTerm (TERM_PROGRAM=iTerm.app) and uses the matching image protocol. On unsupported terminals, slides are listed by path instead.

#Examples

# Quick preview in iTerm/Kitty.
summarize slides "https://youtu.be/..." --render auto

# Big lecture, more granular cuts.
summarize slides "https://youtu.be/..." \
  --slides-max 24 --slides-scene-threshold 0.2

# Pipe-friendly JSON for an automation.
summarize slides "https://youtu.be/..." --json | jq '.slides.slides[].imagePath'

# Force re-extraction after editing the source video.
summarize slides "./talk.mp4" --no-cache -o ./out

#See also