[MEncoder-users] CPU usage in two pass encoding

[James Hastings-Trew]

Stjepan Brbot wrote:
> I use the following mencoder commands for two pass xvid encoding:
>
> mencoder dvd://1 -alang hr -passlogfile FILE.xvid.log \
> -oac mp3lame -lameopts abr:br=128:aq=3:mode=1:vol=2 \
> -ovc xvid -xvidencopts bitrate=1200: ... :threads=2:pass=1:turbo \
> -vf crop=704:544:8:16,scale=600:480 \
> -o /dev/null
>
> mencoder dvd://1 -alang hr -passlogfile FILE.xvid.log \
> -oac mp3lame -lameopts abr:br=128:aq=3:mode=1:vol=2 \
> -ovc xvid -xvidencopts bitrate=1200: ... :threads=2:pass=2 \
> -vf crop=704:544:8:16,scale=600:480 \
> -o FILE.xvid.avi
>
> (tehere are more xvindenc parameters but for sake of simplicity I put
> here only three dots).
>
> In both passes I set "threads=2" but I see that my CPU usage in first
> pass is only 55% while in second pass it is 88% (Of course both passes
> run in the same conditions - no other apps are running.)
>
> What's the reason for different CPU usages of these two passes?
It generally does the same thing on my system with x264 - first pass 
will take 80% cpu, second pass will take 100%. Try setting the threads 
to double the cpu cores you have, and see if it makes a difference with 
the encoding speed.