[FFmpeg-user] FFmpeg CPU usage

Tom Evans tevans.uk at googlemail.com
Tue Aug 13 16:58:52 CEST 2013

On Mon, Aug 12, 2013 at 10:23 PM, Pete <pjjuliana216 at gmail.com> wrote:
>> Please provide an actual, unscripted command and the complete ffmpeg
>> console output.
> By nonscripted I assume you mean the command without the variables. Here it
> is:
> ffmpeg -y -i "inputVid" -c:v libx264 -preset fast -b:v 480k -threads 0 -c:a
> libfdk_aac -b:a 128k -f mp4 "outputVid.mp4"
> here is the ffmpeg output from the server I'm using to transcode:

Close, but no cigar - "complete ffmpeg console output" is the output
of the command you are trying to run. I don't think it matters too
much in this scenario though - you're happy with ffmpeg's output, just
not how long it is taking.

You could try transcoding a few videos with -an (to disable audio) and
see if that dramatically improves fps - otherwise, start checking
whether any component is 100% stressed, eg disk, network, cpu or RAM.
If not, you're likely constrained by CPU.

I know you say that you are not seeing 100% usage across all cores,
bear in mind MT is not 100% efficient. Since you have a veritable
pipeline of videos to transcode, perhaps you should try transcoding N
videos at a time, instead of trying to have N threads transcoding 1
video simultaneously.



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