视频编码 open-gop 与 close-gop 区别

定义

IDR帧是h26x编码中特殊的I帧，IDR后的任何帧都可以去参考IDR前面的帧

open-gop

序列帧的最后的2个B帧会向后参考I帧来实现冗余

close-gop

转码参考

ffmpeg -y -i Haunted_1080p.mp4 -x264-params keyint=60:min-keyint=60:scenecut=0:bframes=2:b-adapt=2:ref=2:open-gop=0 Haunted_closed2.mp4
ffmpeg -y -i Haunted_1080p.mp4 -x264-params keyint=60:min-keyint=60:scenecut=0:bframes=2:b-adapt=2:ref=2:open-gop=1 Haunted_open2.mp4

更多参考：
https://streaminglearningcenter.com/blogs/open-and-closed-gops-all-you-need-to-know.html