[x264-devel] Max thread number of x264

[Alex Jurkiewicz]

Hi,

On 6 April 2010 19:52, kenter <kenter83 at gmail.com> wrote:

> Hi, Experts:
>      I have a server with 24 AMD CPUs equipped, however, when I set x264
> with --threads 36 *(36 means 24*1.5)*, I found the CPU usage only 800+,
> which means only 8 CPU cores are filled.
>

1.5*(logical cores available) is the default, so no need to set it.


>      I also use top -H -p PID to detect the real threads count of x264
> proc, It shows 15 threads runs simutaneous at peak, I need help that How can
> I fully ultilize the CPU power?
>
>     My command line is:
>     SRC_FILE.yuv 720x576
>

You may be constrained by the bandwidth of your disk reading the raw source
file.


> -I 250 -i 25
>

Defaults.


> -b 4 --b-adapt 1 --b-bias 0 --ref 6 --deblock 0:0 --bitrate 500 --qpmin 2
> --qpmax 51 --qpstep 3 --ratetol 8.0 --aq-mode 0 --sar 16:15 --ipratio 1.25
> --pbratio 1.25 --pass 0 --partitions all --cqm flat --direct spatial
> --mvrange-thread 24 --me hex --merange 16 --subme 6 --psy-rd 1.0:0.0
> --mixed-refs --8x8dct --no-chroma-me --no-fast-pskip --trellis 0 --nr 0
> --threads 36 --vbv-bufsize 2000 --vbv-init 0.75  --aq-strength 1
> --chroma-qp-offset 10 --weightb  --fps 25 -o output_file.264
>

Some of those options are defaults (qpmax), some are non-functional
(vbv-bufsize without maxrate) and some are just crazy (pass 0?!). Try this
commandline:
x264 SRC 720x576 --bitrate 500 --preset slow --bitrate 500 --output OUT


>
>     Thanks!
>
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>
>
Alex
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