evo-video-keyframe-extraction
Overview
Extracts keyframes from gameplay video using uniform temporal sampling, saves with zero-padded sequential naming, and converts to grayscale in-place.
Key Concepts
- Uses
cv2.VideoCapturefor video decoding with embedded FFmpeg backend - Uniform temporal sampling: extract 1 frame per second (frame_interval = int(fps * 1.0))
- Frames saved as PNG with
cv2.imwrite()using zero-padded naming:keyframes_001.png,keyframes_002.png, etc. - Grayscale conversion done in-place: read with
cv2.IMREAD_GRAYSCALE, overwrite original file - OpenCV uses BGR channel order (not RGB)
- For a 27-second 60fps video, extracts 27 keyframes (one per second)
Functions
get_video_metadata(video_path)
Returns dict with: fps, frame_count, width, height, duration_seconds
extract_keyframes(video_path, output_dir, sample_interval_seconds=1.0, name_format="keyframes_{:03d}.png")
Extracts keyframes at uniform intervals. Returns list of saved file paths in timeline order.
sample_interval_seconds=1.0means 1 frame per secondname_formatuses Python format string with {:03d} for zero-padded numbering starting at 1- Keyframe counter is 1-based (keyframes_001.png, keyframes_002.png, ...)
convert_frames_to_grayscale(frame_paths)
Converts images to grayscale IN-PLACE (overwrites original files). Returns list of converted paths. Reads with cv2.IMREAD_GRAYSCALE and writes back with cv2.imwrite.
Usage
pythonimport sys sys.path.insert(0, '/app/environment/skills/evo-video-keyframe-extraction/scripts') from video_utils import extract_keyframes, convert_frames_to_grayscale, get_video_metadata # Get video info meta = get_video_metadata('/root/super-mario.mp4') print(f"Duration: {meta['duration_seconds']}s, FPS: {meta['fps']}") # Extract keyframes (1 per second) to /root paths = extract_keyframes('/root/super-mario.mp4', '/root', sample_interval_seconds=1.0) # Convert to grayscale in-place convert_frames_to_grayscale(paths)
