On 01.12.2015 22:59, Lou wrote:
On Tue, 1 Dec 2015 22:19:16 +0100
D <[email protected]> wrote:
I built it with yasm. But $ ffmpeg seems not to display it? Or does it
only display it if it's disabled, so mine is enabled?
ffmpeg version N-76952-g6b978da Copyright (c) 2000-2015 the FFmpeg
developers
built with gcc 5.2.1 (Ubuntu 5.2.1-22ubuntu2) 20151010
configuration: --prefix=/home/username/ffmpeg_build
--pkg-config-flags=--static
--extra-cflags=-I/home/username/ffmpeg_build/include
--extra-ldflags=-L/home/username/ffmpeg_build/lib
--bindir=/home/username/bin --enable-gpl --enable-libass
--enable-libfreetype --enable-libopus --enable-libtheora
--enable-libvorbis --enable-libx264 --enable-nonfree
libavutil 55. 9.100 / 55. 9.100
libavcodec 57. 16.101 / 57. 16.101
libavformat 57. 19.100 / 57. 19.100
libavdevice 57. 0.100 / 57. 0.100
libavfilter 6. 17.100 / 6. 17.100
libswscale 4. 0.100 / 4. 0.100
libswresample 2. 0.101 / 2. 0.101
libpostproc 54. 0.100 / 54. 0.100
That's not the complete console output. The "using cpu capabilities"
output from libx264 is worth noting.
I already posted a full output a few emails ago but here you go again
with my build this time (BTW: so far building ffmpeg myself didn't
change anything vs using static builds from ffmpeg.org/download):
Without "-threads": http://pastebin.com/vHVYdkCf
With "-threads 1": http://pastebin.com/mcWuqS0N
If I omit it it's of course the same as "-threads 4" (I did already test
it and at least this is what I would expect because I have 4 real cores
on a 84W TDP Haswell i5 CPU). See without "-threads 4" down below.
4 cores does not mean that x264 will automatically choose 4 threads.
For example, for my aging i7 860, x264 will use threads=12 (cores*1.5
for frame threads).
That's good info.
I did not read the whole thread, so I'm likely missing something
obvious, why not just use the defaults? Why are you messing around with
threads?
I was just wondering how it scales and found out it doesn't well.
In the console output when using the defaults, what value appears for
"threads=" in the x264 info? (You may have to output to a file instead
of null for it to appear).
Don't know how to see it.
Encode a file. Look at the console output; specifically the long line
that starts something like this:
[libx264 @ 0x55be781c6d40] 264 - core 148 r2579 73ae2d1 ...
Now for the important question: did you also test the x264 cli tool?
Indeed an important question.
$ sudo apt-get install x264
$ time x264 --pass 1 --crf 23 --preset ultrafast --threads 1 -o "b.mp4"
"a.mp4"
real 1m33.883s
[...]
So unfortunately basically the same as with ffmpeg.
In this case your questions should be asked at x264 help resources.
That's what I thought too.
PS: I tested HandBrake with HandBrake-GUI. It uses ~387% in top (which
is good so far and utilized the CPU better than any other of my tests
(well, VP9 did but the output files were corrupted and unreadable)) but
I couldn't test with e.g. "-threads 1" and so on and see how it scales.
Maybe it's possible with the -CLI version. I wonder what settings the
GUI creates and forwards to x264, so I could take them and just add
"-threads n" and see how it scales.
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