video-understand
Understand video content locally using ffmpeg for frame extraction and Whisper for transcription. Fully offline, no API keys required.
Prerequisites
ffmpeg+ffprobe(required):brew install ffmpegopenai-whisper(optional, for transcription):pip install openai-whisper
Commands
# Scene detection + transcribe (default)
python3 skills/video-understand/scripts/understand_video.py video.mp4
# Keyframe extraction
python3 skills/video-understand/scripts/understand_video.py video.mp4 -m keyframe
# Regular interval extraction
python3 skills/video-understand/scripts/understand_video.py video.mp4 -m interval
# Limit frames extracted
python3 skills/video-understand/scripts/understand_video.py video.mp4 --max-frames 10
# Use a larger Whisper model
python3 skills/video-understand/scripts/understand_video.py video.mp4 --whisper-model small
# Frames only, skip transcription
python3 skills/video-understand/scripts/understand_video.py video.mp4 --no-transcribe
# Quiet mode (JSON only, no progress)
python3 skills/video-understand/scripts/understand_video.py video.mp4 -q
# Output to file
python3 skills/video-understand/scripts/understand_video.py video.mp4 -o result.json
CLI Options
| Flag | Description |
|---|---|
video | Input video file (positional, required) |
-m, --mode | Extraction mode: scene (default), keyframe, interval |
--max-frames | Maximum frames to keep (default: 20) |
--whisper-model | Whisper model size: tiny, base, small, medium, large (default: base) |
--no-transcribe | Skip audio transcription, extract frames only |
-o, --output | Write result JSON to file instead of stdout |
-q, --quiet | Suppress progress messages, output only JSON |
Extraction Modes
| Mode | How it works | Best for |
|---|---|---|
scene | Detects scene changes via ffmpeg select='gt(scene,0.3)' | Most videos, varied content |
keyframe | Extracts I-frames (codec keyframes) | Encoded video with natural keyframe placement |
interval | Evenly spaced frames based on duration and max-frames | Fixed sampling, predictable output |
If scene mode detects no scene changes, it automatically falls back to interval mode.
Output
The script outputs JSON to stdout (or file with -o). See references/output-format.md for the full schema.
{
"video": "video.mp4",
"duration": 18.076,
"resolution": {"width": 1224, "height": 1080},
"mode": "scene",
"frames": [
{"path": "/abs/path/frame_0001.jpg", "timestamp": 0.0, "timestamp_formatted": "00:00"}
],
"frame_count": 12,
"transcript": [
{"start": 0.0, "end": 2.5, "text": "Hello and welcome..."}
],
"text": "Full transcript...",
"note": "Use the Read tool to view frame images for visual understanding."
}
Use the Read tool on frame image paths to visually inspect extracted frames.
References
references/output-format.md-- Full JSON output schema documentation