遇到webrtc只能播放264 baseline 的profile的情况，high profile播放不出来，暂时留作记录，继续研究
FFmpeg基础知识之————H264编码profile & level控制
https://www.cnblogs.com/lidabo/p/7419393.html
https://blog.51cto.com/fengyuzaitu/3130901
webrtc支持264
https://blog.csdn.net/foruok/article/details/69525039
https://www.freesion.com/article/9497592473/
https://blog.piasy.com/2020/01/04/WebRTC-H264-Profile-Levels/index.html
https://blog.csdn.net/liang12360640/article/details/52096499
ffmpeg循环推流：
https://blog.csdn.net/cai6811376/article/details/74783269/
