How to reduce cpu load with ffmpeg libx264?

Question

Video

There is a simple vps with one core, it is transcoding the stream from rtsp to rtmp. If you drive the stream one to one 1920 * 1080, the processor load is about 2-5%.

ffmpeg 
-i rtsp://localhost/$app/$name
-c copy 
-f flv rtmp://localhost:1935/show_decode/$name_src

but as soon as I try to reduce the video resolution to hd720 using libx264 codec, the load immediately increases to 20-30%, which hits performance very hard

- disabling audio does not help
- preset ultrafast \ superfast \ veryfast ... works, but the maximum decreases to 20%
- crf 23, almost does not help, maximum 1-2% with maximum deterioration

ffmpeg 
-i rtsp://localhost/$app/$name
-c:v libx264 
-c:a aac 
-b:v 1920k 
-b:a 128k 
-vf "scale=1280:trunc(ow/a/2)*2" 
-tune zerolatency 
-preset ultrafast 
-crf 23 
-f flv rtmp://localhost:1935/show_decode/$name_hd720

How can I reduce the CPU load even more?

Answer 1

Logically, ffmpeg starts to shovel the video stream. Maybe it's better to take the second 720p stream from the camera to another ffmpeg?