Large number of ffmpeg threads issue

[vahid75]

Although in slide,presentation and processor files i specify 1 ffmpeg thread should handle the jobs , it it bloated the CPU with large number of threads.
see this command output:
ps -eLf | grep ffmpeg | grep -v grep | wc -l
returns 82 .
also see this output:
ps -eLf | grep ffmpeg | grep -v grep
there are 82 lines exactly like this one bellow

ffmpeg -hide_banner -loglevel error -threads 1 -i ./tmp/datafBlKlI/slides.mp4 -i /var/bigbluebutton/published/presentation/0bcf39e84e94b53f25e1803ccaedc22efd810fa6-1644647011762/video/webcams.webm -filter_complex [0:v]pad=width=1440:height=600:color=white[p];[p][1:v]overlay=x=800:y=0[out] -map [out] -map 1:1 -c:a aac -shortest -y ./tmp/datafBlKlI/video.mp4

i think it is the reason behind generating bbb videos takes too long . sometimes about 2 hours or more for a 170mb recording dir.
also tweaking number of CPUs doesn't affect time consumed to generating video files .
thanks