ffmpeg Cheat Sheat for downgrade mp4

Change Resolution

ffmpeg -i input.mp4 -vf scale=1280:720 -c:v libx264 -crf 23 -preset medium -c:a copy output.mp4

If you dont want to change aspect ratio,

ffmpeg -i input.mp4 -vf scale=1280:-1 -c:v libx264 -crf 23 -preset medium -c:a copy output.mp4

Change frame rate

ffmpeg -i input.mp4 -r 15 -c:v libx264 -crf 23 -preset medium -c:a copy output.mp4