2019 great x265 4k settings?

[excellentswordfight]

Originally Posted by Nico8583

Hi,
I tried some settings and some encodes but I can see every time x265 lose a lot of details, even with a high bitrate (2 pass 35 MBits, CRF16...)
Do you have some tricks to encode ?
Thank you !

Preset slow, or lower, and --no-sao --no-strong-intra-smoothing --deblock -1:-1.

Sounds a bit odd that you lose a lot of detail at crf16 though (unless you are using a fast preset). Mind sharing settings and some samples?

[Nico8583]

Thank you.
I'm using slower or veryslow and no-sao, I'll try others settings. And I'll share my settings and samples.
I'm using Captain America Civil War chapter 17 to make my tests.

[~ VEGETA ~]

how much time does it take to finish your encode? I have an ATOM 2750 CPU dedicated server (yes I know it is not suited for encoding) and it is so slow. I wonder what affordable cpu I could use\buy to suit hevc 1080p encodes? any suggestions?

[Forteen88]

Originally Posted by ~ VEGETA ~

...
I wonder what affordable cpu I could use\buy to suit hevc 1080p encodes? any suggestions?

You should wait until AMD releases their 7nm CPU:s this summer. Intel's CPU-prices (if you're an Intel-fanboi :)) will drop then too.

[excellentswordfight]

Originally Posted by Forteen88

You should wait until AMD releases their 7nm CPU:s this summer. Intel's CPU-prices (if you're an Intel-fanboi ) will drop then too.

Well with the latest Intel generation prices went up rather then down even with Ryzen2 released though... The prices could drop, but I woudlnt just assume that they do.

There is very little information that suggest that Ryzen3 will do much to increase general performance in a significant way. However there are two things that are very promising for the target group on this forum. AVX-performance and probably an 16C/32T mainstream modell.

[Nico8583]

So you think it's better to wait Ryzen 3 instead of buy a i9 9900K or i7 9700K ?

[excellentswordfight]

Originally Posted by Nico8583

So you think it's better to wait Ryzen 3 instead of buy a i9 9900K or i7 9700K ?

In this case yes, with the improved AVX performance of Ryzen3 they should give a nice pump in price/performance over the current offering for encoding. But if money isnt a big issue, and you think that you are fine with 16threads, 9900k isnt a bad option. It will still be fast, and probably faster then ryzen3 thread for thread. But I'm pretty sure we will get an 12c/24t chip that is priced under 9900k.

[Nico8583]

Yes you're probably right, Ryzen 3 should be released soon so I can wait thank you

[redbtn]

I don't wanna start new topic for small question, so I decided ask for help here.
I'm encoding 4k HDR > 1080p HDR with preset Slower, CRF 12-13 with output bitrate 16-17mbps. And my question is how much --merange and --ctu affects to quality?

For example:

--ctu 64 --merange 57 (2.5fps)
--ctu 32 --merange 26 (2.83fps) +13% speed

Avg QP is the same, output file size almost the same (428.2mb vs 428.5mb).

Is it worth spending 13% speed?

Ps: I have i5-9400f 6 core cpu, so just lowering --ctu don't give me boost on speed, all boost from lowering --merange.

My full settings:

--level-idc 51 --sar 1:1 --colorprim 9 --colormatrix 9 --transfer 16 --range limited --master-display "G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1)" --max-cll "0,0" --hdr --hdr-opt --hrd --chromaloc 2 --repeat-headers --min-luma 0 --max-luma 1023 --no-cutree --no-sao --selective-sao 0 --no-open-gop --no-b-pyramid --no-strong-intra-smoothing --vbv-bufsize 160000 --vbv-maxrate 160000 --min-keyint 23 --keyint 240 --ipratio 1.30 --pbratio 1.20 --deblock -3:-3 --qcomp 0.65 --aq-mode 2 --aq-strength 0.8 --psy-rd 2 --psy-rdoq 2 --rd 4 --limit-refs 3 --bframes 8 --rc-lookahead 60 --subme 5 --me star --ctu 32 --merange 26 --max-merge 4

[benwaggoner]

Originally Posted by redbtn

I don't wanna start new topic for small question, so I decided ask for help here.
I'm encoding 4k HDR > 1080p HDR with preset Slower, CRF 12-13 with output bitrate 16-17mbps. And my question is how much --merange and --ctu affects to quality?

For example:

--ctu 64 --merange 57 (2.5fps)
--ctu 32 --merange 26 (2.83fps) +13% speed

I'd get nervous about having a small merange when working at 4K resolution, but that would be content dependent. Visual comparison is probably required here.

And most 4K content can wind up using 64x64 CTUs. It's probably a bigger deal at lower bitrates.

[Blue_MiSfit]

I found that restricting CTU does improve speed a lot and can improve sharpness with lower resolution content... BUT this sharpness improvement was only visible when doing frame by frame comparison AND it came at the cost of more blocking in motion which was significantly more visible in ordinary viewing.

My tests are always done using single pass capped VBR set up for adaptive streaming, so take that with a grain of salt, but I found leaving CTU and merange alone gave me the best results. I found preset slow to be quite tolerable in all cases.

[Boulder]

I would definitely use CTU 64 at 1080p and above, also the new HME method to improve the search range with a smaller impact on performance. At 1080p or higher resolutions, CTU 64 should already cause enough work for the encoder to utilize the CPU much better than at 720p or lower so there should be no need to go to CTU 32.

[redbtn]

Thank you all for response.

Originally Posted by Boulder

I would definitely use CTU 64 at 1080p and above, also the new HME method to improve the search range with a smaller impact on performance. At 1080p or higher resolutions, CTU 64 should already cause enough work for the encoder to utilize the CPU much better than at 720p or lower so there should be no need to go to CTU 32.

What's your advice for 1080p? CTU 64, Merange 57 and HME umh, umh, star?
Or I need lower merange like 32 for compensate impact HME on speed? I still don't understand actually how HME works and better way to use it.

[vpupkind]

Originally Posted by redbtn

? I still don't understand actually how HME works and better way to use it.

You run motion estimation on 1/16th your resolution, scale the motion vector you found, and search around it on 1/4th resolution.
You then scale the motion vector from the 1/4th resolution, and search around it at full resolution.

[Boulder]

Originally Posted by redbtn

Thank you all for response.

What's your advice for 1080p? CTU 64, Merange 57 and HME umh, umh, star?
Or I need lower merange like 32 for compensate impact HME on speed? I still don't understand actually how HME works and better way to use it.

In my opinion, you can lower merange with HME because it will cause a much higher range to be searched anyway (as vpupkind described there).

Although I don't know which way it works -- from full to low resolution or the other way around.
This description, http://homepages.inf.ed.ac.uk/rbf/CV...stimation.html , shows level 0 as one with the full resolution.

Then the description of the patch has this information:

This patch does the following:
1) Perform level-0 ME
2) Use the MVs as predictor for next level ME
3) Restrict full-search within a range when HME is enabled

In these cases, it would be really nice to have a clear explanation in the docs

[redbtn]

Originally Posted by Boulder

In my opinion, you can lower merange with HME because it will cause a much higher range to be searched anyway (as vpupkind described there).



Although I don't know which way it works -- from full to low resolution or the other way around.

This description, http://homepages.inf.ed.ac.uk/rbf/CV...stimation.html , shows level 0 as one with the full resolution.



Then the description of the patch has this information:



This patch does the following:

1) Perform level-0 ME

2) Use the MVs as predictor for next level ME

3) Restrict full-search within a range when HME is enabled



In these cases, it would be really nice to have a clear explanation in the docs

Yeah, there is not enough info in docs about it.
I'm worried about this http://forum.doom9.org/showthread.php?p=1881016
Is it relevant to the option --refine-mv which is changed to 1 by default for now?

I've done some tests:

--merange 57 --no-hme 2.21fps
--merange 57 --hme umh, umh, star 1.74 fps
--merange 40 --hme umh, umh, star 1.90 fps
--merange 32 --hme umh, umh, star 1.96 fps
--merange 26 --hme umh, umh, star 2.04 fps

So, 27% between HME off and HME on with same merange.
Well, the question is what is better, --merange 57 --no-hme or --merange 26 --hme, cuz defference in speed between them not so much

[Boulder]

In theory, HME is higher quality even if you use merange 26 (because the effective merange is much higher than that). But if you need to know for sure, you need to test. It could well be that in a normal live action video, you can't tell the difference between the two.

EDIT: the message in that link is one reason why I would like to see the devs explain things a bit, like what kind of material they have tested etc.

[benwaggoner]

Originally Posted by redbtn

So, 27% between HME off and HME on with same merange.
Well, the question is what is better, --merange 57 --no-hme or --merange 26 --hme, cuz defference in speed between them not so much

There isn't any psychovisual tuning involved here, so looking at PSNR and SSIM differences would probably be a lot more useful than with other settings.

My gut is a smaller range with HME is probably optimal at fixed encoding time, but it'll be somewhat content dependent. HME is probably more useful to improve perf @ quality than anything else.

[redbtn]

Originally Posted by benwaggoner

My gut is a smaller range with HME is probably optimal at fixed encoding time, but it'll be somewhat content dependent. HME is probably more useful to improve perf @ quality than anything else.

Thanks for your reply! I use for 4k encoding this settings with Preset Slow and as i know the red ones affect to speed:

--rd 4 --limit-refs 3 --bframes 8 --rc-lookahead 72 --me star --max-merge 4 --ref 4 --subme 5 --weightb --b-intra --tu-intra-depth 3 --tu-inter-depth 3 --no-cutree --no-sao --no-open-gop --no-strong-intra-smoothing --ipratio 1.35 --pbratio 1.25 --deblock -3:-3 --qcomp 0.65 --aq-mode 2 --aq-strength 0.8 --psy-rd 2 --psy-rdoq 2

So, maybe i should use something like --no-rect for compensate slowdown and use --hme umh, umh, star? Or maybe decrease some other settings. I mean, it will more useful to improve perf @ quality?
I ask cuz my speed for now is 1-1.1 fps and i don't wanna go much lower than 1.0 fps

I'll do some tests with PSNR and SSIM tomorrow.

[Boulder]

I'd drop subme down to 3 as per the preset.