Ffmpeg

Skill cxcscmu/SkillLearnBench/skills/human_authored/video-object-counting/ffmpeg

[COLM'26] SkillLearnBench is the first benchmark for evaluating continual learning methods that automatically generate agent skills.

Install

npx -y skills add cxcscmu/SkillLearnBench --skill ffmpeg

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What its author says it does

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Extract key frames (I-frames) from video files using FFmpeg command line tool. Use this skill when the user needs to pull out keyframes, thumbnails, or important frames from MP4, MKV, AVI, or other video formats for analysis, previews, or processing.

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SKILL.md

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FFmpeg Keyframe Extraction

Extract key frames (I-frames) from video files using FFmpeg CLI.

Prerequisites

FFmpeg installed and available in PATH
Input video file (MP4, MKV, AVI, MOV, etc.)

Methods

Method 1: Select Filter (More Control)

ffmpeg -i <input_video> -vf "select='eq(pict_type,I)'" -vsync vfr <output_pattern>
Method 2: Skip Frame (Faster)

ffmpeg -skip_frame nokey -i <input_video> -vsync vfr <output_pattern>
Key Options
Option	Description
-i <file>	Input video file
-vf "select='eq(pict_type,I)'"	Filter selecting only I-frames
-skip_frame nokey	Skip decoding non-keyframes (performance)
-vsync vfr	Variable frame rate, prevents duplicates
-q:v <n>	Quality (1-31, lower = better, for JPEG)
-frame_pts 1	Use presentation timestamp in filename
Output Patterns
frame_%03d.png - PNG sequence (frame_001.png, frame_002.png...)
frame_%03d.jpg - JPEG sequence
frame_%d.bmp - BMP sequence
Examples
Basic PNG extraction:

ffmpeg -i video.mp4 -vf "select='eq(pict_type,I)'" -vsync vfr keyframe_%03d.png High-quality JPEG:

ffmpeg -i video.mp4 -skip_frame nokey -vsync vfr -q:v 2 keyframe_%03d.jpg With timestamps:

ffmpeg -i video.mp4 -vf "select='eq(pict_type,I)'" -vsync vfr -frame_pts 1 keyframe_%d.png


To specific directory:

ffmpeg -i video.mp4 -vf "select='eq(pict_type,I)'" -vsync vfr ./output/keyframe_%03d.png