declare -i x=1
 while [ x != 200 ]
 do
    videoName=$(find -iname "*1080p*" | sort | sed -n "${x}p")
    ffmpeg -i $videoName -filter_complex "[0:v][0:s:0]overlay[v]" -map "[v]" -map 0:a:0 -c:v h264_nven>
    x=$x+1
 done

ffmpeg -i input.mkv -map 0:v:0 -map 0:a -map 0:s -c:v libx264 -c:a copy -c:s copy -preset slow -crf 22 output.mkv