cut video

ffmpeg $start_time $length -i "$1" -vcodec copy -an -cpu-used 2 -threads 2 $height -sn ~/"$1 s $start_time_var l $length_var".mp4

scale=-1:720,pad=1280:ih:(ow-iw)/2

ffplay -i test2.mp4 -vf scale=-1:480,pad=848:ih:\(ow-iw\)/2

ffmpeg -i anime16_9_t4_041.mp4 -vf scale=-1:480 jopa.mp4

ffmpeg -i smotri.mp4 -i jopa.mp4 -i kakaya.mp4 -filter_complex "[0]setdar=16/9[a];[1]setdar=16/9[b];[2]setdar=16/9[c]; [a][b][c]concat=n=3:v=1:a=0 [v]" -map "[v]" result.mp4

ffmpeg -i zzz.mp3 -i result.mp4 out.mp4