Due to the use of the SDK lira flow have influence to B frame, need to push flow of time to remove B frame,
Before is:
Ffmpeg - re - I hot - pop6. Mp4 - vcodec libx264 - bf - acodec aac - strict - 2-0 f FLV RTMP://* * * *
This is no problem, but the CPU is too high, which is the top view are 100%,

Now changed to:
Ffmpeg - re - I 400298. Mp4 - threads 2 - c copy - fit: a aac_adtstoasc - bf 0 f FLV RTMP://* * * * *
The CPU utilization is very low very low, but bf - this function and have no effect to remove the B frame, whether and - fit: a aac_adtstoasc have conflict?

Please know that the great god of some directions, the second how to change to without transcoding is in addition to B frame (mainly is the need to reduce the CPU usage)