How do I extract video frames for editing one at a time?

Question

I'm trying to apply graphicsmagick v1.3.42 filters/resizing to frames from videos extracted with ffmpeg v6.1.

The process of extracting and resizing all frames uses alot of space, I want to iterate and edit each frame individually if thats possible?

I use: ffmpeg6 -i "input_video.mp4" output_frames/frame%04d.png to get the frames.

then:

for filename in  output_frames/*.png; do
    gm convert "$filename" -median 2 -filter Mitchell -resize 400% -unsharp 0x0.75+0.75+0.008 "$filename"
done
# Reassemble video from frames and audio
ffmpeg6 -i output_frames/frame%04d.png -i input.mp3 -c:v libx264 -r 25 -pix_fmt yuv420p -c:a copy -shortest output_video.mp4

Answer 1

Limit yourself to key frames. Use this ffmpeg option.

-skip_frame nokey