https://blog.wongcw.com/2018/12/09/centos6-7%e7%b3%bb%e7%bb%9f%e5%ae%89%e8%a3%85ffmpeg%e7%bb%99mp4%e8%a7%86%e9%a2%91%e5%88%87%e7%89%87%e4%b8%bam3u8/