x265 HEVC Encoder

Originally Posted by phate89

I have a question (i'm not an expert but i want to understand better the reasons). If i understood well google with vp9 while working on 10/12 bit wants to switch everything to 16 bit internally and other decoders already do this. Why x265 keeps 2 separate files and the 8 bit one is only 8 bit?
I understand that the advantage of higher internal precision is very small but it will slow down a lot more or the speed is the same? Will x265 join the 2 branches in the future?

Basically, an 8 bit encoder will run almost twice as fast as an encoder that is using 16 bits to store and process each color sample. Modern microprocessors support data types and instructions that can store and process multiple data samples in one instruction. This concept is called Single Instruction Multiple Data, or SIMD. More specifically, these instructions include Streaming SIMD Extensions (SSE), or Advanced Vector Extensions (AVX). In a 128 bit wide register the 8 bit build of x265 can store and operate on sixteen 8 bit color samples. The high bit depth (16 bit) build can only store and operate on eight 16 bit data samples with each SSE or AVX instruction. So, when you use twice the width for each data sample, you move and process data at half the speed.

Conceptually, I suppose we could compile both 8 bit and 16 bit versions of x265 into separate libraries, then create a single executable that would call the right library at run-time, but the executable would be twice as large, and it would take longer and be more difficult to build and maintain. Choosing the right library to use is really a job for application developers.

[IgorC]

Originally Posted by Atak_Snajpera

x265 --crf 20 --preset medium --rd 6 --psy-rd 1.0 (average bitrate 1060 kbps) - ENCODING TIME : 22m55s
https://mega.co.nz/#!kM80wCTI!rIhFZ4...dgi_7dlLY0f-a4

x264 --crf 21 --preset veryslow (average bitrate 1031 kbps) - ENCODING TIME : 9m22s
https://mega.co.nz/#!0ZcxzajB!QjH8qs...ScXX1s3WR01K5E

Originally Posted by Atak_Snajpera

Latest Xvid + slowest settings enabled + 2-pass
https://mega.co.nz/#!IZFmBDqI!4oIPL_...R025T7e1W_ZWAA

Great. Thank You. Just was watching for HEVC vs H.264 comparison. I can't decide between x264 and x265.
x264 has more details at cost of more noise. x265 has more stability in motion.
And xvid was clearly inferior to both. Disabling/Enabling post-processing in Xvid oficial decoder doesn't help here.

I don't understand people yelling about testing at 500 kbps. What is it? year 2004? 640x272?
Even Youtube uses 1 Mbit+ for 720p(VP9/H.264). Also a projection of results from low bitrate to high are generally misleading.

Originally Posted by Atak_Snajpera

Similar history with audio compression. 48Khz HE-AAC@32kbps with parametric stereo will definitely sound better than mp3 with the same bitrate and so what. The question is : Will you be encoding your FLAC collection for your ipod/smatphone using such ridiculously low bitrate??? I do not think so! Most likely you will be using something between 64kbps-128kbps.

Exactly.
HE-AACv2@32kbps is better than MP3@32kbps. Though HE-AACv2@128kbps is considerably worse than MP3@128kbps.

Same valid for video codecs. One particular H.264 encoder can be better than MPEG2 at low bitrates. But if MPEG2 presererves fine details/grain good enough while one H.264 encoder doesn't do that then the situation can change at high bitrates.

Nothing new was said here. Just some simple logic and observations.

[2Bdecided]

Originally Posted by IgorC

HE-AACv2@128kbps is considerably worse than MP3@128kbps.

?

At 128kbps, a half-decent HE-AACv2 encoder should switch off PS and SBR, just giving you standard AAC - which beats mp3 at 128kbps.

I guess if you force it to use PS, or force it to use SBR at a low-ish frequency, it would sound worse.

Back (vaguely) on topic: current broadcast encoders seem to favour the AVC tools in HEVC...
http://www.obe.tv/about-us/obe-blog/item/13-a-look-at-the-hevc-encoder-bbc-uhd-world-cup-part-2

Cheers,
David.

[Sagittaire]

Well, I make visual test on psy-rdo and with default setting, I have big local temporal quality flicking (seem not be a spacial quality problem). I make investiquation and psy-rdo seem have big problem on I-P-B frame transition.

For solve that I reduce the ratio quality between frame type ... and I have good result on my sample test. Psy-rdo seem work (on my sample test) even with high value if you choose low ratio quality between frame type.

x265.exe --input hp.yuv --output crf23aq.265 --input-res 720x304 --fps 25 --crf 24 --preset veryslow --aq-mode 2 --aq-strength 1.0 --psy-rd 0.5 --bframes 3 --min-keyint 1 --ipratio 1.1 --pbratio 1.1 --psnr

[Sagittaire]

Originally Posted by IgorC

Exactly.
HE-AACv2@32kbps is better than MP3@32kbps. Though HE-AACv2@128kbps is considerably worse than MP3@128kbps.

Same valid for video codecs. One particular H.264 encoder can be better than MPEG2 at low bitrates. But if MPEG2 presererves fine details/grain good enough while one H.264 encoder doesn't do that then the situation can change at high bitrates.

Nothing new was said here. Just some simple logic and observations.

No, it's really false simply because you choose 16 bits, 44.1 Khz, 2 channel source. There are many other properties than bitrate for Audio and for Video too.

- HE-AAC at 128 Kbps will be better than mp3 at 128 Kbps and by far if you choose 5.1 channel or 96 Khz source. HE-AAC 5.1 48Khz or HE-AAC 2.0 96Khz will produce better audio experience than equivalent MP3 2.0 48Khz at 128 Kbps and by far ... ;-)

- It's the same thing for video. 5 Mbps HEVC at 720x576 will be certainely not really better than 5 Mbps MPEG2 and even perhaps worst is some situation. Anyway 5 Mbps HEVC at 4K will produce uncomparable video experience if you compare at 5 Mbps MPEG2 in all resolution.

[LigH]

Version 1.2 is coming soon™; in the meantime, have v1.1+258-6623f1195baa (most recent stable+default merge) in my MediaFire archive.

[Sagittaire]

Well this time no doubt, x265 outperform x264 even with particular short sample like park_joy_1080p50.y4m. Psy-RDO work very well.

http://jfl1974.free.fr/park_joy_1080p50_x265.mp4

[LigH]

And there is version 1.2; just waiting for the verbose summary.

[Atak_Snajpera]

Originally Posted by Sagittaire

Well this time no doubt, x265 outperform x264 even with particular short sample like park_joy_1080p50.y4m. Psy-RDO work very well.

http://jfl1974.free.fr/park_joy_1080p50_x265.mp4

Liar!

https://mega.co.nz/#!wFMw0ICR!QGqoZB...pDyJFqRxsSqH78

[Sagittaire]

Originally Posted by Atak_Snajpera

Liar!

https://mega.co.nz/#!wFMw0ICR!QGqoZB...pDyJFqRxsSqH78

Well I confirm that my x265 encoding is better than your x264 encoding ... and by far. Make screenshoot if you want tak_Snajpera (And buy a white cane or dog)

In order:
- More temporal stability for x265 and by far
- Less mosquito noise for x265 and by far
- less blocking for x265 and by far
- more high frequency retention (detail) for x265 and by far

Mosquito noise and detail retention are not the same thing ... !!!

[Atak_Snajpera]

Originally Posted by Sagittaire

Well I confirm that my x265 encoding is better than your x264 encoding ... and by far. Make screenshoot if you want tak_Snajpera (And buy a white cane or dog)

In order:
- More temporal stability for x265 and by far
- Less mosquito noise for x265 and by far
- less blocking for x265 and by far
- more high frequency retention (detail) for x265 and by far

Mosquito noise and detail retention are not the same thing ... !!!

And ofcourse you have forgotten about the most important thing. DETAILS x265 blurs everything like crazy. See grass , see water , see leaves. They must pay you for spreading those lies no doubt!

x264 frame 100
http://i.cubeupload.com/mVSONo.png

x265 frame 100
http://i.cubeupload.com/Oc3H1z.png

[a5180007]

First frame : http://screenshotcomparison.com/comparison/82931

EDIT :
Although overall movie sizes are the same
x264 1st I-frame is 90,534 bytes, avg QP 34
x265 1st I-frame is 47,600 bytes, avg QP 40

Very different decisions... @Sagittaire : what are the encoding parameters?

Funny to see how the "banding artefacts" are related to the CTUs.
There is definitely something borked with psy-rd reconstruction.

[fumoffu]

How about my x264 encode: http://a.pomf.se/onaaol.mkv (ugh.. sry filehost changes file names)
It looks similar to x265 but water is much better.

[Sagittaire]

Originally Posted by Atak_Snajpera

And ofcourse you have forgotten about the most important thing. DETAILS x265 blurs everything like crazy. See grass , see water , see leaves. They must pay you for spreading those lies no doubt!

x264 frame 100
http://i.cubeupload.com/mVSONo.png

x265 frame 100
http://i.cubeupload.com/Oc3H1z.png

Well, I don't like Screenshoot but like your eyes are really strange I will make that with the same frame 100:



Like you can see, x265 high frequency retention is by far better for x265. You say "more detail for x264" and I say "hard mosquito noise for x264" (and I prove that with your screen).

When I compare x265 vs x264 encoding I see:
- Hard temproral instability for x264
- Major blocking hellfest for x264
- Major Ringing hellfest for x264

For last time MOSQUITO NOISE IS NOT DETAIL RETENTION ... !!!

[Atak_Snajpera]

My eyes are fine. The problem is with your damaged brain. For some odd reason it prefers blured image instead of sharper with higher complexity. I hope they pay you well atleast for your trolling...

[poisondeathray]

Some strange issues with that red umbrella ghosting / echo image?

[Sagittaire]

Originally Posted by Atak_Snajpera

My eyes are fine. The problem is with your damaged brain. For some odd reason it prefers blured image instead of sharper with higher complexity. I hope they pay you well atleast for your trolling...

Seriousely, In YOUR screen you prefer x264 ... ???

It's Ringing and Blocking hellfest ... lol

I can't even see some head on x264 encoding. For you, good detail prevervation must cut the head ...

And I use the same frame 100 than your screenshoot. Really easy for me to find other frame with really bad quality for x264 and bad detail preservation.

[a5180007]

@Sagittaire: could you please give the encoding parameters.

EDIT : will x265 write the encoding parameters in the SEI like x264 does in a near future?
I find it very annoying not to be able to see these parameters when downloading a x265 encoding.

@Atak_Snajpera : the x264 image is a Degas painting, the x265 is a Monet painting. Some like Monet, some others prefer Degas.
At this level of compression it is impressionism rather than reflecting reality. What is the point of testing at those crf when lower resolutions give better quality?

[Atak_Snajpera]

at low bitrate both encodes look bad. x264 is at least sharper. Grass , leaves ,water in x265 is noticable less detailed. I imediatelly notice that in motion.

[Sagittaire]

Originally Posted by poisondeathray

Some strange issues with that red umbrella ghosting / echo image?

Yes I see that for x265. It's certainely temporal artefact because here the quantification is really high. Anyway I find temporal stability and global quality really better for x265. There are major flicking in x264 encoding for I-P-B frame transition.