[FFmpeg-user] FPS drop when transcode 3 Full HD channel to SD

chronek chronek at interia.eu
Tue Jun 13 18:41:31 EEST 2017


Hi,

You have dual core cpu, you show that with 1 ffmpeg it use 77% of one 
core (so like ~40% of cpu), with 2 ffmpeg it use 90% of first and second 
core (so like 90% of cpu), with 2 ffmpeg it uses almost all cpu, so no 
wonder that with 3 ffmpeg it slowing down because it need 1,5 more cpu,  
you would need have at least 40% better cpu to run all 3 ffmpeg... With 
3 ffmpeg it using all cpu, some slowed to take 50% of core when it 
needed 77-90%...

Did you compile ffmpeg by self? Some good gcc flags can speed up ffmpeg...


chronek

W dniu 2017-06-13 o 15:03, Hendrik Karsimin pisze:
> Hi,
> I've been trying to transcode the Full HD Channel (1920x1080) to SD
> (720x576).
>
> When I transcode 1 channel, the resulting video is no problem. So are when
> transcode 2 channel.
> But when the 3rd channel I tried to transcode start. the FPS start to drop
> on all the channel I transcoding.
>
> I'm not sure if it's a computer hardware limitation or the software
> limitation.
> But I have tried to change some parameter of ffmpeg, and settle on the last
> ffmpeg configuration I use now.
>
> Attached is the information I collect on the PC I use to transcode.
>
> The Ubuntu Version I use is Ubuntu 14.04.5
>
> #lsb_release -a
> No LSB modules are available.
> Distributor ID: Ubuntu
> Description:    Ubuntu 14.04.5 LTS
> Release:        14.04
> Codename:       trusty
>
> #uname -a
> Linux Compaq 3.13.0-119-generic #166-Ubuntu SMP Wed May 3 12:18:55 UTC 2017
> x86_64 x86_64 x86_64 GNU/Linux
>
> Need advice to resolve this problem.
>
>
>
> *Thanks & regards,*
> Hendrik
>
>
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