Video upload-php uses ffmpeg to transcode mp4 for a long time

I found a ffmpeg code that supports h264 encoding. php calls exec to use ffmpeg for a long transcoding time and the CPU usage exceeds 80%. how can I solve this problem. What are the meanings of the parameters in the transcoding command? {Code...} found a ffmpeg code that supports h264 encoding. php calls exec to use ffmpeg for a long transcoding time and the CPU usage exceeds 80%. how can this problem be solved.
What are the meanings of the parameters in the transcoding command?

$ Command = '.. \ ffmpeg \ bin \ ffmpeg.exe-I '. $ file. '. '. $ ext. '-vcodec libx264-vprofile main-preset slow-B: v 400 k-maxrate 400 k-bufsize 800 k-vf scale =-1: 480-threads 0-acodec libvo_aacenc-AB 128 k '. $ file. '.mp4 ';

Reply content:

I found a ffmpeg code that supports h264 encoding. php calls exec to use ffmpeg for a long transcoding time and the CPU usage exceeds 80%. how can I solve this problem.
What are the meanings of the parameters in the transcoding command?

$ Command = '.. \ ffmpeg \ bin \ ffmpeg.exe-I '. $ file. '. '. $ ext. '-vcodec libx264-vprofile main-preset slow-B: v 400 k-maxrate 400 k-bufsize 800 k-vf scale =-1: 480-threads 0-acodec libvo_aacenc-AB 128 k '. $ file. '.mp4 ';

Use Qiniu for conversion or asynchronous queue

Specific command man ffmpeg