Convert from .mkv to Android web playable .mp4

ffmpeg -i 1.txt 1.ass
EP=1 bash -c 'ffmpeg -i $EP.mkv -crf 24 -pix_fmt yuv420p -vf "ass=$EP.ass, scale=-1:720" -c:v h264 -preset:v superfast -ac 2 -c:a aac -movflags +faststart $EP.mp4'

-i x.txt/x.srt x.ass - generate subtitles

-crf 24 - for lower bitrate -pix_fmt yuv420p - for Android playback (pixel format) -vf "ass=$EP.ass, scale=-1:720" - hardcode subtitles, change resolution -c:v h264 - reencode video -preset:v superfast - speed up reencoding -ac 2 - 5.1 -> stereo -c:a aac - reencode audio -movflags +faststart - enable simple web playback and file navigation