blured background for short / reel

ffmpeg -i test.mp4 -filter_complex "[0:v]split=2[fg][bg];[fg]scale=1080:-2[fgs];[bg]scale=1080:1920:force_original_aspect_ratio=increase,boxblur=30:30,crop=1080:1920[bgf];[bgf][fgs]overlay=(W-w)/2:(H-h)/2" -c:v libx264 -pix_fmt yuv420p -r 60 -movflags +faststart -c:a copy output.mp4 -y



combine

ffmpeg -i ins.mp4 -i reel.mp4 -filter_complex "[0:v]setsar=1[v0];[1:v]setsar=1[v1];[v0][v1]concat=n=2:v=1:a=0[v];[1:a]adelay=5000|5000[a]" -map "[v]" -map "[a]" -c:v libx264 -pix_fmt yuv420p -c:a aac combined.mp4


rotate video

ffmpeg -i cut.mp4 -vf "transpose=1" reel.mp4