[FFmpeg-user] libvpx-vp9 not using all 4 real cores (no HT CPU) like libx264 does (in top: ~250% vs ~387%)
tevans.uk at googlemail.com
Thu Nov 26 11:54:52 CET 2015
On Wed, Nov 25, 2015 at 2:47 PM, D <dcmhoybdpzkh at web.de> wrote:
> Continuing and splitting up the problem which I have here:
> The problem is that libx264 utilizes all 4 cores almost to the 400% ($ top),
> as it should be, but when using libvpx-vp9, it's only ~250%.
> $ cd ffmpeg-git-20151124-64bit-static
> No Problem:
> Almost 100% on all 4 cores if I use:
> $ ./ffmpeg -i a.mp4 -c:v libx264 -crf 23 -c:a libvorbis b.mp4
> Only 1 core used, not all 4 cores like with libx264, but also on 100% if I
> $ ./ffmpeg -i a.mp4 -c:v libvpx-vp9 -crf 23 -c:a libvorbis b.webm
> And trying to use all 4 cores, although all 4 cores are used now, it's only
> on ~60-75% utilization (~250% in top):
> $ ./ffmpeg -i a.mp4 -c:v libvpx-vp9 -crf 23 -cpu-used 4 -threads 4 -c:a
> libvorbis b.webm
> (changing -cpu-used and -threads higher than 4 values was neither faster
> nor slower).
> What do you think? (See already mentioned suggestions in 029274.html thread.
> They unfortunately didn't help.)
> John, the maintainer of the "Linux Static Builds"
> (https://ffmpeg.org/download.html), says it might be due to libvpx-vp9 not
> being optimized yet and maybe someone else has an idea.
> Can anyone try these libvpx-vp9 commands and say how many % in $ top are
> My OS is Ubuntu 15.04 but I don't think this is the reason. My CPU has no HT
> support, only 4 real cores (84W TDP Haswell).
Do you get the same results using vpxenc and the appropriate flags?
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