Smooth Scrubbing Web Video FFMPEG Mega Command

encode.sh

ffmpeg -i input.mp4 -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3 -an -vf "scale=-1:1440, reverse" -preset veryslow -g 2 output.mp4

// -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3
// Encode for web with a good balance of browser compatibility and compression ratio

// -an
// Strip audio tracks

// -vf "scale=-1:1440, reverse"
// Scale video to 1440px wide, maintaining aspect ratio
// And reverse the video (remove if not necessary)

// -preset veryslow
// Longer encode time on machine, better quality output

// -g 2
// SUPER IMPORTANT
// -g specifies the interval of Key Frames, in this case make every 2nd frame a Key Frame
// Standard compressed videos that just play through normally or continuously loop
// should have a low Key Frame count to save on file size. But a high number of keyframes
// is crucial for smooth scrubbing and forward/reverse playback.
// -g 1, meaning every single frame is a KeyFrame would be the smoothest, but basically doubles the file size.
// -g 2, seems like a good balance of very smooth playback with decent file size.
// -g values much higher than two will start to produce noticeable lag between key frames when scrolling.