grab-videos（抓取视频）

Grab Videos and Frames Skill

Download videos and extract frames using yt-dlp + ffmpeg.

Quick Reference

YouTube Download

# Download best quality
yt-dlp -f best "https://www.youtube.com/watch?v=XXXX"

# Download Shorts playlist (first 20)
yt-dlp "https://www.youtube.com/@user/shorts" --playlist-items 1-20

# List available formats
yt-dlp -F "https://www.youtube.com/watch?v=XXXX"

# Download specific format (e.g., 1080p)
yt-dlp -f "best[height<=1080][ext=mp4]" "https://www.youtube.com/watch?v=XXXX"

# Download audio only
yt-dlp -x "https://www.youtube.com/watch?v=XXXX"

Frame Extraction

# Single frame at timestamp
ffmpeg -ss 5 -i video.mp4 -vframes 1 -q:v 2 frame.jpg

# Random frame (5-15 seconds)
ffmpeg -ss $((RANDOM % 11 + 5)) -i video.mp4 -vframes 1 -q:v 2 frame.jpg

# Frames every N seconds
ffmpeg -i video.mp4 -vf "fps=0.5" frame_%03d.png  # every 2s

# Scale down for thumbnails
ffmpeg -ss 10 -i video.mp4 -vf "scale=640:-1" -vframes 1 -q:v 5 thumb.jpg

# Batch from all videos
for f in *.mp4; do ffmpeg -ss 5 -i "$f" -vframes 1 "${f%.mp4}_thumb.jpg"; done

Batch Operations

# Download multiple URLs
for url in "url1" "url2" "url3"; do yt-dlp "$url"; done

# Extract frame from each video
for f in *.mp4 *.webm; do [ -f "$f" ] || continue; dur=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$f"); rnd=$((RANDOM % 11 + 5)); ffmpeg -ss "$rnd" -i "$f" -vframes 1 "frames/${f%.mp4}_${rnd}s.jpg" -y; done

Output Directory

# Recommended structure
workspace/
├── downloads/     # Raw videos
├── frames/        # Extracted frames
├── thumbnails/    # Small thumbs
└── clips/         # Trimmed clips

Important Notes

• Rate limits: YouTube may rate-limit excessive downloads
• Format support: yt-dlp supports 1700+ sites
• Storage: Videos can be large; use -f best[height<=720] for smaller files
• Permissions: May need chmod +x for scripts
• yt-dlp JS: Requires Node.js or deno for some YouTube formats
• Installation: Need install yt-dlp and ffmpeg tools with apt install <tool-name> on Linux and with brew install <tool-name> on macOS,

or ask user to download it from https://github.com/yt-dlp/yt-dlp/releases and https://ffmpeg.org/download.html

Common Patterns

Download + extract 1 frame:

yt-dlp -o video.mp4 "https://www.youtube.com/watch?v=XXXX"
ffmpeg -ss 5 -i video.mp4 -vframes 1 -q:v 2 thumb.jpg

Thumbnail batch:

mkdir -p thumbnails
for f in *.mp4; do ffmpeg -ss 5 -i "$f" -vf "scale=320:-1" -vframes 1 -q:v 5 "thumbnails/${f%.mp4}.jpg" -y; done

Duration check:

ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 video.mp4

Extented Abilities and skills

Learn other abilities and skills from yt-dl help

yt-dlp --help

Learn other abilities and skills from ffmpeg help

ffmpeg -h