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 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 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
Notes
Method 2 (-skip_frame nokey) is faster as it skips decoding non-keyframes Method 1 offers more filtering flexibility (can combine with other filters) Keyframe frequency depends on video encoding settings Use -vsync vfr to avoid duplicate frames in output