[FFmpeg-user] scale input video before transcoding

[jacob s]

command:
*ffmpeg -f dshow -i video="screen-capture-recorder":audio="SoundMAX Digital
Audio"  -vcodec  libx264 -preset ultrafast -tune film -r 10 -async 1 -ab
32k -ar 22050 -f mpegts udp://192.168.5.215:48550*
console output:

http://pastebin.com/1zQKKZe4

command:

*ffmpeg -f dshow -i video="screen-capture-recorder":audio="SoundMAX Digital
Audio" -vf "scale=iw/2:ih/2" -vcodec  libx264 -preset ultrafast -tune film
-r 10 -async 1 -ab 32k -ar 22050 -f mpegts udp://192.168.5.215:48550*
console output:

http://pastebin.com/AG8juKkU

> Did you test encoding to a file instead of udp?
> What speed / CPU usage do you see?

I tried encoding to file and cpu was the same ( around 65%)

Can you help me reduce CPU usage, these Pentium 4 machines are weak in CPU
power and it causes the stream to glitch and freeze, this is why I am
trying to scale the input and hopefully it will reduce CPU usage ( no luck
so far ) .


2012/3/12 Carl Eugen Hoyos <cehoyos at ag.or.at>

> jacob s <jacobhameiri <at> gmail.com> writes:
>
> > -f dshow -i video='screen-capture-recorder':audio='Stereo
> > Mix (IDT High Definition' -vcodec  libx264 -preset ultrafast
> > -r 10 -async 1 -ab 32k -ar 22050 -f mpegts udp://192.168.2.100:1234
>
> Complete, uncut console output missing.
>
> > When using this command ffmpeg uses about 65% CPU
> > ( Pentium4 2.8 GHz ), and after a short while I am
> > seeing glitches in the viewing machine.
>
> Note that the Pentium4 has known limitations
> (that may or may not be the reason for your problems).
>
> > I thought of reducing CPU usage by scaling the input video
> > to 50% - 75%, but even after scaling to 50% CPU usage doesn't
> > change, I suspect this is
>
> Command line and complete, uncut console output missing.
>
> > because the scaling is performed after the transcoding process
>
> It is not possible to scale after transcoding
> (all scaling has to be done after decoding and before encoding).
>
> Did you test encoding to a file instead of udp?
> What speed / CPU usage do you see?
>
> Carl Eugen
>
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