LinuxSystems

I wanted to know something about the actual x265 development state and since I didn’t find anything up to date I decided to do my own tests.
First of all I compiled a recent snapshot of x265:

./x265 --version
x265 [info]: HEVC encoder version 0.7+259-5e2043f89aa1
x265 [info]: build info [Linux][GCC 4.8.2][64 bit] 8bpp
x265 [info]: using cpu capabilities: MMX2 SSE SSE2Fast SSSE3 SSE4.2 AVX

x264 –version
x264 0.142.2389 956c8d8
built on Feb 21 2014, gcc: 4.8.2
configuration: –bit-depth=8 –chroma-format=all
x264 license: GPL version 2 or later

This is my 112s / 216MB test video:
https://mega.co.nz/#!eQhSjJQR!EEe8-taN5IspIu-RW0WQzmvKzc5fkCn282kS5ugZ_as

Let’s encode it using x265 first:

ffmpeg -v 0 -i ~/PlanetEarthBirds.mkv -threads 4 -vsync 0 -an -pix_fmt yuv420p -f yuv4mpegpipe - | ./x265 - --y4m --preset placebo --crf 28 -o prova.h265

As you can see I used ffmpeg to decode the video and then I piped the raw stream to the x265 encoder. I did a quality based encoding with the default crf (28) which gives low quality but low size output files (considering my source isn’t lossless this is exactly what I want to easily spot differences with x264).

Then I generated a file of the very same size using two pass encoding with x264:

ffmpeg -v 0 -i ~/PlanetEarthBirds.mkv -threads 4 -vsync 0 -an -pix_fmt yuv420p -f yuv4mpegpipe - | x264 - --demuxer y4m --preset placebo -o prova.h264 --pass 1 --bitrate 3310
ffmpeg -v 0 -i ~/PlanetEarthBirds.mkv -threads 4 -vsync 0 -an -pix_fmt yuv420p -f yuv4mpegpipe - | x264 - --demuxer y4m --preset placebo -o prova.h264 --pass 2 --bitrate 3310

Here is the result:

-rw-r--r-- 1 niko niko 46094455 22 feb 04.19 prova.h264
-rw-r--r-- 1 niko niko 46238768 21 feb 21.26 prova.h265

As you can see prova.h264 is 46094455 bytes (~45MB) while prova.h265 is 46238768 bytes (~45MB). The video encoded with x264 is just 0.14MB smaller which is a 0.3% difference.

Using the placebo presets I used the slowest settings which are supposed to give the best quality for both encoders.
Having to use two pass encoding for x264 to make a meaningful comparison there is no sense comparing encoding speed, so I will not do it.

Here are the encoded files:
prova.h264
prova.h265

Anyway we can compare DECODING speeds
Let’s decode them as fast as we can using ffh264 (FFmpeg H.264) and ffhevc (FFmpeg HEVC / H.265):

mplayer -benchmark -nosound -lavdopts threads=16 prova.h264 -vo null 2> /dev/null

BENCHMARKs: VC: 5.640s VO: 0.003s A: 0.000s Sys: 0.333s = 5.976s
BENCHMARK%: VC: 94.3730% VO: 0.0482% A: 0.0000% Sys: 5.5788% = 100.0000%

mplayer -benchmark -nosound -lavdopts threads=16 prova.h265 -vo null 2> /dev/null

BENCHMARKs: VC: 26.936s VO: 0.003s A: 0.000s Sys: 0.360s = 27.300s
BENCHMARK%: VC: 98.6680% VO: 0.0123% A: 0.0000% Sys: 1.3197% = 100.0000%

As you can see the video encoded with x264 took 5.976s to decode while the x265 one took 27.300s.
h265 actually takes 4.6x more time than h264 to decode. Not bad, really.

Let’s take some screenshots:

mplayer -lavdopts threads=16 -nosound -benchmark -fps 23.976 -vf framestep=275 -vo png:z=9 prova.h264; for i in `ls -l *png | awk '{ print $9 }' | grep -v h26 | grep -v source`; do mv $i x264-test1-$i; done
mplayer -lavdopts threads=16 -nosound -benchmark -fps 23.976 -vf framestep=275 -vo png:z=9 prova.h265; for i in `ls -l *png | awk '{ print $9 }' | grep -v h26 | grep -v source`; do mv $i x265-test1-$i; done
mplayer -lavdopts threads=16 -nosound -benchmark -fps 23.976 -vf framestep=275 -vo png:z=9 ~/PlanetEarthBirds.mkv; for i in `ls -l *png | awk '{ print $9 }' | grep -v h26 | grep -v source`; do mv $i source-test1-$i; done

Finally, let’s compare them:

x264 vs x265
http://files.linuxsystems.it/functions/comparison.php?test=test1&codec1=x264&codec2=x265&number=1
http://files.linuxsystems.it/functions/comparison.php?source=planetearthbirds&bitrate1=3310&codec1=x265-0.7-259-5e2043f89aa1-8bpp-placebo&bitrate2=3310&codec2=x264-0.142.2389-956c8d8-8bpp-placebo&n=10&current=1

source vs x265
http://files.linuxsystems.it/functions/comparison.php?test=test1&codec1=source&codec2=x265&number=1
http://files.linuxsystems.it/functions/comparison.php?source=planetearthbirds&bitrate1=source&codec1=x265-0.7-259-5e2043f89aa1-8bpp-placebo&bitrate2=3310&codec2=x265-0.7-259-5e2043f89aa1-8bpp-placebo&n=10&current=1

Press F11 to switch your browser to the full screen mode and click on the image to switch from the x265 screenshots to source or x264. I also put some previous/next buttons (there are 10 png screenshots in total).

I don’t want to be critical because x265 is still in early stages of development, but as you can see it completely washed the video: details are gone. Sometimes x265 did a better job but overall x264 definitely wins.
Keep up the good work devs 😉