Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.

 

Go Back   Doom9's Forum > Video Encoding > High Efficiency Video Coding (HEVC)

Reply
 
Thread Tools Search this Thread Display Modes
Old 25th September 2022, 18:02   #1  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
x265 Sharpness and Detail (Best Settings?)

Hi,

I'm looking to find settings that increase detail and sharpness. In turn, I'm also looking for settings that apply blurring or softness and can be turned off.

Here are the settings that I know of so far that do this.
  1. subme=7 (A sharpener, detail increase)
  2. no-deblock / deblock (Blurring/detail loss the more deblock is used)
  3. no-sao / sao (High Blur)
  4. no-strong-intra-smoothing / strong-intra-smoothing (Smoother/Blur)
  5. psy-rd=-- & psy-rdoq=-- rdoq-level=-- (Detail increase as the cost of accuracy - Can look over-digital)


These are all the detail increase settings that I know of so far. Are there any more? I saw some things on QBlur, I don't know what it does, because I haven't researched it. Just because blur is in the title made me think, but is this anything that controls sharpness and detail?

Are there any more? My goal is to get the most detailed image possible use x265 (which is notorious for having a soft image). However, if anything goes over the top, like, giving an edge-enhanced look or heavy ringing, I will back off. The goal is maximum blur removal and ultra-high detail without looking overly digital, this is why I'm trying to back off from using psy-rd and rdoq, I just don't like the look personally.

Thank you.

Last edited by HD MOVIE SOURCE; 25th September 2022 at 18:05.
HD MOVIE SOURCE is offline   Reply With Quote
Old 26th September 2022, 21:12   #2  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
[QUOTE=HD MOVIE SOURCE;1975282]Hi,

I'm looking to find settings that increase detail and sharpness. In turn, I'm also looking for settings that apply blurring or softness and can be turned off.

Here are the settings that I know of so far that do this.
  1. subme=7 (A sharpener, detail increase)
  2. no-deblock / deblock (Blurring/detail loss the more deblock is used)
  3. no-sao / sao (High Blur)
  4. no-strong-intra-smoothing / strong-intra-smoothing (Smoother/Blur)
  5. psy-rd=-- & psy-rdoq=-- rdoq-level=-- (Detail increase as the cost of accuracy - Can look over-digital)
I am unaware of any evidence that --strong-intra-smoothing reduces visible detail in any scenario.
Nor does --deblock if used appropriately. Both will reduce detail at moderate-low bitrates, as they reduce compression efficiency and drive QPs higher, which itself is a low-pass filter. The HEVC built-in deblocking filter is better turned than H.264's.

--subme only goes up to 5 in --preset placebo. I've not seen visible quality improvements from using higher values.

If you have sharp synthetic details (text, line art, noise-free anime), --tskip can increase detail.

In theory --hme can help with very noisy content.
--amp and --rect can improve detail by allowing TUs to better match the shape of content, for example encoding a mild horizontal curve as 32x8 instead of forcing it to be square.

But in general, a lot of these things are controlled by the preset. It's best to pick the slowest preset that is fast enough, and start tweaking from there.

Quote:
These are all the detail increase settings that I know of so far. Are there any more? I saw some things on QBlur, I don't know what it does, because I haven't researched it. Just because blur is in the title made me think, but is this anything that controls sharpness and detail?
That "blurrs" differences in QP to reduce quality fluctuations. It has no direct impact on sharpness.

Quote:
Are there any more? My goal is to get the most detailed image possible use x265 (which is notorious for having a soft image). However, if anything goes over the top, like, giving an edge-enhanced look or heavy ringing, I will back off. The goal is maximum blur removal and ultra-high detail without looking overly digital, this is why I'm trying to back off from using psy-rd and rdoq, I just don't like the look personally.
I'd start doing a test encode at --preset slower --crf 18 --no-sao and see if the detail retention and file size are okay for you. If not, tweak from there. Jumping in with parameters without having some reference encodes to compare with the source and each other makes for a lot more work.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 29th September 2022, 18:08   #3  |  Link
BuccoBruce
Registered User
 
Join Date: Apr 2022
Posts: 28
I'm going to second and expand upon benwaggoner's great advice.
  • Don't turn deblock off completely
  • Don't turn SAO off completely
You will see more artifacts, or end up wasting bits trying to prevent them. It isn't 2015 anymore, they don't destroy detail or sharpness in most scenarios.

For deblock, you should turn the strength down and turn the threshold up instead of disabling it outright. Start with --deblock -1:1 and work your way down/up from there to taste. I personally wouldn't go higher than 1 on the threshold, and I don't think I've seen any encodes "in the wild" with threshold >1 either. Some people use e.g. -2:0.

For SAO, I'm not sure what the "best" option is, but I use --limit-sao --selective-sao 1 --sao-non-deblock to "reel it in" as opposed to turning it off completely, and it has been working well for me. Now that I look at the documentation, --selective-sao 3 might be a better choice. I'm not sure why you'd ever want SAO on non-reference slices though, so definitely use at least one of those two choices, or "2" if you don't want it on any reference B slices.

--amp --rect and --tskip-fast are all indispensable for animated content, if you can stomach all the extra time they consume. I haven't tried them with live action content.

--hme is pretty useful for getting away with using a lower subme and knocking slower presets down to --me umh at higher resolutions, although I personally haven't seen any benefit from using it at 1080p and below.
BuccoBruce is offline   Reply With Quote
Old 29th September 2022, 23:27   #4  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
--selective-sao 2 is the one you want, and should be the x265 default. SAO is designed around forward-prediction only, so 99% of the value is seen on just I and P frames. Applying it to B and b frames just slows the encode down a bit. In theory I could imagine --selective-sao 3 maybe helping a tiny bit in some odd scenarios, but don't have any evidence or examples of that.

What impact have you found from --sao-non-deblock? I don't think I've ever tried it (which is pretty rare!). I'd presumed it was a quality-versus-performance tradeoff parameter.

And yeah, cel animation and motion graphics require much different tuning that natural image content. Motion blur and noise make a huge difference compared to not having those.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 1st October 2022, 06:16   #5  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
Thank you for the feedback guys, much appreciated. And yes, I have been encoding from the basic preset first and then adjusting from there.

I personally can't stand using sao, its way too aggressively soft, I just don't think it's needed, at least on high bit-rate content like 4k UHD Blu-ray. Streaming maybe another matter or low bit-rates, but I will not use sao, that's the opposite direction I want to go.


"-tskip can increase detail" --- Is this okay to use in grainy content too?


"In theory --hme can help with very noisy content" --- This doesn't remove noise or grain though does it? as long as it doesn't remove anything, Ill try it.


--amp and --rect I will look into, I know they add quite a bit of encoding time so I will have to think about these.


Right now I'm encoding SolLevante from Netflix which is grain free but has ultra-fine details. When she dives down into the ocean, I want to retain as much of the ultra-fine detail that the source has. I also thinking about grain content also. i want to preserve as much grain as possible also, without blurring or blending anything.

Ill run a few encodes with these new settings. Thank you.

Last edited by HD MOVIE SOURCE; 1st October 2022 at 06:26.
HD MOVIE SOURCE is offline   Reply With Quote
Old 2nd October 2022, 04:45   #6  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
Quote:
Originally Posted by benwaggoner View Post

--subme only goes up to 5 in --preset placebo. I've not seen visible quality improvements from using higher values.

If you have sharp synthetic details (text, line art, noise-free anime), --tskip can increase detail.

In theory --hme can help with very noisy content.
--amp and --rect can improve detail by allowing TUs to better match the shape of content, for example encoding a mild horizontal curve as 32x8 instead of forcing it to be square.

But in general, a lot of these things are controlled by the preset. It's best to pick the slowest preset that is fast enough, and start tweaking from there.


That "blurrs" differences in QP to reduce quality fluctuations. It has no direct impact on sharpness.


I'd start doing a test encode at --preset slower --crf 18 --no-sao and see if the detail retention and file size are okay for you. If not, tweak from there. Jumping in with parameters without having some reference encodes to compare with the source and each other makes for a lot more work.

Okay, I added tskip, hme amp, and rect to my encoding settings. The sharpness is off the chain right now. It's pin sharp. The facial detail on SolLevante looks as thought it was drawn with a pencil it looks that sharp.

The biggest issue is the encoding time. It took about 16 hours just to encode SolLevante and that was about 4 minutes of content. I was encoding this in 2 and a half hours before these settings. I'm just using an old PC to encode with overnight. If I want to encode using these settings I will definitely have to get an optimized encoding PC.

The settings I used that have an effect in detail.
  1. subme=7
  2. no-deblock
  3. no-sao
  4. no-strong-intra-smoothing
  5. psy-rd=0.00, psy-rdoq=0.00, rdoq-level=0
  6. (I dislike everything the RD and RDOQ does to the image, I think it makes the image look too digital, so I set those to 0 and get my detail with other settings that don't look digital)
  7. tskip
  8. hme
  9. amp
  10. rect

The sharpness is extremely impressive, I didn't think x265 was capable of this level of detail. Thank you, now you'll have to send me an encoding PC LOL.

Last edited by HD MOVIE SOURCE; 2nd October 2022 at 04:53.
HD MOVIE SOURCE is offline   Reply With Quote
Old 4th October 2022, 02:21   #7  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
Quote:
Originally Posted by HD MOVIE SOURCE View Post
Okay, I added tskip, hme amp, and rect to my encoding settings. The sharpness is off the chain right now. It's pin sharp. The facial detail on SolLevante looks as thought it was drawn with a pencil it looks that sharp.

The biggest issue is the encoding time. It took about 16 hours just to encode SolLevante and that was about 4 minutes of content. I was encoding this in 2 and a half hours before these settings. I'm just using an old PC to encode with overnight. If I want to encode using these settings I will definitely have to get an optimized encoding PC.

The settings I used that have an effect in detail.
  1. subme=7
  2. no-deblock
  3. no-sao
  4. no-strong-intra-smoothing
  5. psy-rd=0.00, psy-rdoq=0.00, rdoq-level=0
  6. (I dislike everything the RD and RDOQ does to the image, I think it makes the image look too digital, so I set those to 0 and get my detail with other settings that don't look digital)
  7. tskip
  8. hme
  9. amp
  10. rect

The sharpness is extremely impressive, I didn't think x265 was capable of this level of detail. Thank you, now you'll have to send me an encoding PC LOL.
I'd start with just --preset slower --selective-sao 2 and adjust from there. --preset slower enables fast modes of the slower tools where available, and generally is targeting your kind of scenario overall.

If that doesn't give you the detail you want, first try --no-sao.

If you find --tskip helpful, try --tskip --tskip-fast.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 4th October 2022, 22:19   #8  |  Link
microchip8
ffx264/ffhevc author
 
microchip8's Avatar
 
Join Date: May 2007
Location: /dev/video0
Posts: 1,846
Quote:
Originally Posted by HD MOVIE SOURCE View Post
Okay, I added tskip, hme amp, and rect to my encoding settings. The sharpness is off the chain right now. It's pin sharp. The facial detail on SolLevante looks as thought it was drawn with a pencil it looks that sharp.

The biggest issue is the encoding time. It took about 16 hours just to encode SolLevante and that was about 4 minutes of content. I was encoding this in 2 and a half hours before these settings. I'm just using an old PC to encode with overnight. If I want to encode using these settings I will definitely have to get an optimized encoding PC.

The settings I used that have an effect in detail.
  1. subme=7
  2. no-deblock
  3. no-sao
  4. no-strong-intra-smoothing
  5. psy-rd=0.00, psy-rdoq=0.00, rdoq-level=0
  6. (I dislike everything the RD and RDOQ does to the image, I think it makes the image look too digital, so I set those to 0 and get my detail with other settings that don't look digital)
  7. tskip
  8. hme
  9. amp
  10. rect

The sharpness is extremely impressive, I didn't think x265 was capable of this level of detail. Thank you, now you'll have to send me an encoding PC LOL.
I've no idea how you came to the conclusion that Psy setting make the image too "digital". Both psy-rd and psy-rdoq, at *high* values, virtually completely elliminate banding artifacts. So, either disable psy-rd/psy-rdoq and enjoy your banding or turn them on at high values and enjoy a clean, crisp image.

I've been encoding for ages with high psy-rd/psy-rdoq and have yet to see it destroy detail or sharpness. At worse, it makes the image more "static".
__________________
ffx264 || ffhevc || ffxvid || microenc
microchip8 is offline   Reply With Quote
Old 4th October 2022, 22:25   #9  |  Link
rwill
Registered User
 
Join Date: Dec 2013
Location: Berlin, Germany
Posts: 375
Quote:
Originally Posted by microchip8 View Post
I've no idea how you came to the conclusion that Psy setting make the image too "digital". Both psy-rd and psy-rdoq, at *high* values, virtually completely elliminate banding artifacts. So, either disable psy-rd/psy-rdoq and enjoy your banding or turn them on at high values and enjoy a clean, crisp image.

I've been encoding for ages with high psy-rd/psy-rdoq and have yet to see it destroy detail or sharpness. At worse, it makes the image more "static".
Well he has not mentioned the bitrate, crf or qp he encodes at. For all we know he could be pushing 500Mbit/s and marvel at the transparent quality.
rwill is offline   Reply With Quote
Old 8th October 2022, 01:52   #10  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
Quote:
Originally Posted by benwaggoner View Post
I'd start with just --preset slower --selective-sao 2 and adjust from there. --preset slower enables fast modes of the slower tools where available, and generally is targeting your kind of scenario overall.

If that doesn't give you the detail you want, first try --no-sao.

If you find --tskip helpful, try --tskip --tskip-fast.
Thank you Ben.

One thing I've noticed is that no-hme is used in all 10 presets by default. Is this because the encoding time added is huge by using hme? I have tried it on SolLevante, but it's a very short piece of material so I could get away with it. But, unless you have a supercomputer I don't think hme is even viable to setups like mine.

I will run some speed tests on the other settings and see what I can get away with. As long as it can add detail and not take away with minimal impact on encoding time, I'm fine with that.

I cannot encode a full movie using beyond medium. Medium and a movie of about 90 minutes is around 2 days. But, I am well aware my current encoding PC is woefully inadequate. However, for now I'm fine with it. I don't mind an encode taking 4 or 5 days, that's fine, but anything over a week is not something I can achieve right now. So I will test each setting to see the speed impact.

Thanks.

Quote:
Originally Posted by rwill View Post
Well he has not mentioned the bitrate, crf or qp he encodes at. For all we know he could be pushing 500Mbit/s and marvel at the transparent quality.
I'm encoding at uhd-bd=1 maxrate which is around 98 Mbps. That's my target bit-rate. I use Constant Rate Factor = 0. But that doesn't mean that you don't have bit-rate control. Bit-rates can still bit controlled by using vbv-maxrate=98000:vbv-bufsize=99000. When using maxrate with CFR it essentially becomes the target bit-rate, and buffsize basically turns into maxrate when compared to a 2-pass encode. I read this in the x265 docs, and since doing it my encodes look incredible.

What this does is makes it so anything under my target bit-rates is essentially transparent, and anything getting up to 98 Mbps is so high in bit-rate that it basically transparent also.

SolLevante was encoded using these settings and my final average bit-rate is 68.7 Mb/s. The average QP is 8.21.

If you want to see my encode for SolLevate here it is: https://drive.google.com/file/d/1v8-...W0kKVV2St/view

Somebody mentioned banding in a previous comment. Using aq-mode=3 and aq strength of 1.6 removes banding entirely for me. I tested this over and over again and 1.6 gives you the lowest QP (highest quality possible). Going above 1.6 lowers the quality. With SolLevante using 1.6 and aq-mode=3 removes all banding on a professionally calibrated LGC9 OLED.

Last edited by HD MOVIE SOURCE; 8th October 2022 at 02:07.
HD MOVIE SOURCE is offline   Reply With Quote
Old 8th October 2022, 23:13   #11  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
Quote:
Originally Posted by HD MOVIE SOURCE View Post
One thing I've noticed is that no-hme is used in all 10 presets by default. Is this because the encoding time added is huge by using hme? I have tried it on SolLevante, but it's a very short piece of material so I could get away with it. But, unless you have a supercomputer I don't think hme is even viable to setups like mine.
The bigger reason is probably that --hme wasn't done the last time the presets were implemented. I honestly haven't seen that much benefit from using it for single-stream encoding. In theory it might help quality at UHD resolution with a lot of grain/noise.

The primary use case for that the --hme infrastructure was built around was to encode lower resolutions of the bitrate ladder and use the analysis data from that to encode the next resolution up a lot faster.

So 540 -> 1080 -> 2160 and 360 -> 720 -> 1440.

Using the --hme command lets you emulate the quality impact of doing the above, but without the speed benefits. I'm not sure how much parallelism is implemented in there; the speed hit could be a lot less or even get faster with enough cores if properly threaded.

--hme also allows for different search ranges and methods to be used for each resolution tier, which would allow for finer-grained quality and performance tuning.

Quote:
I cannot encode a full movie using beyond medium. Medium and a movie of about 90 minutes is around 2 days. But, I am well aware my current encoding PC is woefully inadequate. However, for now I'm fine with it. I don't mind an encode taking 4 or 5 days, that's fine, but anything over a week is not something I can achieve right now. So I will test each setting to see the speed impact.
I find a high quality, high bitrate 4K HDR encode takes me about 24 hours per hour of source on my somewhat old workstation, using --pools to pin each encode to one socket of: "Intel(R) Xeon(R) Gold 6240 CPU @ 2.60GHz, 2594 Mhz, 18 Core(s), 36 Logical Processors."

If I'm doing content-specific tuning, I can make it 2-3x faster without significant visible quality loss as I can turn off tools that don't help in that particular case. Things like --tu-inter/intra 4 and --tskip can help a lot with some content and do nothing for other content.

Quote:
I'm encoding at uhd-bd=1 maxrate which is around 98 Mbps. That's my target bit-rate. I use Constant Rate Factor = 0. But that doesn't mean that you don't have bit-rate control. Bit-rates can still bit controlled by using vbv-maxrate=98000:vbv-bufsize=99000. When using maxrate with CFR it essentially becomes the target bit-rate, and buffsize basically turns into maxrate when compared to a 2-pass encode. I read this in the x265 docs, and since doing it my encodes look incredible.

What this does is makes it so anything under my target bit-rates is essentially transparent, and anything getting up to 98 Mbps is so high in bit-rate that it basically transparent also.

SolLevante was encoded using these settings and my final average bit-rate is 68.7 Mb/s. The average QP is 8.21.
Yeah, a mean QP of ~8 is going to look really good almost irrespective of what you do! This is reliant on having a really high bitrate, though.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 9th October 2022, 09:37   #12  |  Link
Boulder
Pig on the wing
 
Boulder's Avatar
 
Join Date: Mar 2002
Location: Finland
Posts: 5,753
If you are going to hit bitrates that high, why bother re-encoding at all?
__________________
And if the band you're in starts playing different tunes
I'll see you on the dark side of the Moon...
Boulder is offline   Reply With Quote
Old 10th October 2022, 02:49   #13  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
Quote:
Originally Posted by Boulder View Post
If you are going to hit bitrates that high, why bother re-encoding at all?
The original file of SolLevante from Netflix has a bit-rate of 1200 Mbps, which is not a re-encode.

However, I have re-encoded many things like Big Buck Bunny, Tears of Steel, and others just for science, and just for fun. I like to see how close to the original source I can get.

Quote:
Originally Posted by benwaggoner View Post
Yeah, a mean QP of ~8 is going to look really good almost irrespective of what you do! This is reliant on having a really high bitrate, though.
Yeah, it looks incredible. How do you know when it's a good time to use tskip? The settings do offer incredible detail, if it's possible to encode at 1 hour per day and use these settings that would be really cool.
HD MOVIE SOURCE is offline   Reply With Quote
Old 10th October 2022, 17:10   #14  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
Quote:
Originally Posted by HD MOVIE SOURCE View Post
The original file of SolLevante from Netflix has a bit-rate of 1200 Mbps, which is not a re-encode.

However, I have re-encoded many things like Big Buck Bunny, Tears of Steel, and others just for science, and just for fun. I like to see how close to the original source I can get.
That's an interesting mix of content. Sol Levante is one of the most challenging clips I've ever seen, and Big Buck Bunny one of the easiest. Neither are particularly representative of mainstream content. Tears of Steel is the most representative of typical TV/movie content, with a mix of live action and CGI.

Quote:
Yeah, it looks incredible. How do you know when it's a good time to use tskip? The settings do offer incredible detail, if it's possible to encode at 1 hour per day and use these settings that would be really cool.
I use --tskip when there are very sharp visual elements with low noise. CGI, cel animation, text, titles, and credits all can benefit. Live action with some noise rarely gets as much value.

In general, --tskip is useful in similar scenarios where --tu-inter/intra 4 are helpful. And the even slower --cu-lossless only really helps when --tskip is already helpful, or at extremely high bitrates.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 10th October 2022, 22:28   #15  |  Link
HD MOVIE SOURCE
Registered User
 
HD MOVIE SOURCE's Avatar
 
Join Date: Mar 2021
Location: North Carolina
Posts: 138
Quote:
Originally Posted by benwaggoner View Post
That's an interesting mix of content. Sol Levante is one of the most challenging clips I've ever seen, and Big Buck Bunny one of the easiest. Neither are particularly representative of mainstream content. Tears of Steel is the most representative of typical TV/movie content, with a mix of live action and CGI.


I use --tskip when there are very sharp visual elements with low noise. CGI, cel animation, text, titles, and credits all can benefit. Live action with some noise rarely gets as much value.

In general, --tskip is useful in similar scenarios where --tu-inter/intra 4 are helpful. And the even slower --cu-lossless only really helps when --tskip is already helpful, or at extremely high bitrates.
Though I have been encoding at 98 Mbps, SolLevante is definitely difficult content to encode. There's lots of complex movements, and I have seen artifacts in the past. While I was encoding that, I started from scratch and there must have been some odd settings that were causing issues because I never see any breakup now.

I'd like to try a really slow encode one time with all the detail settings that you have provided just for fun.

I always though tskip was a speed increase, but it's definitely a speed loss. Is -tskip-fast a weaker version of tskip?

Thanks for the help.
HD MOVIE SOURCE is offline   Reply With Quote
Old 13th October 2022, 17:55   #16  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
Quote:
Originally Posted by HD MOVIE SOURCE View Post
I always though tskip was a speed increase, but it's definitely a speed loss. Is -tskip-fast a weaker version of tskip?
--tskip definitely slows things down. --tskip-fast reduced the speed impact, but can miss some cases where tranform skip would have been better that straight --tskip would have found. But you certainly get most of the benefit with a lot less of the speed hit using --tskip --tskip-fast.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 13th October 2022, 18:40   #17  |  Link
jpsdr
Registered User
 
Join Date: Oct 2002
Location: France
Posts: 2,330
I have an encode running and it will finish only on a few days, so i can't make tests right now (and also can't check the speed difference), so i'll ask...
Is tskip enabled in slower preset ? (Or in any preset)
Is tskip significant, on 4k HDR 10 bits, on multipass encode, average 40000, maxrate 90000 vbv-buffsize 70000 ?
In any case, from what i've understood, --tskip --tskip-fast will always be better than without tskip, if tskip is realy too slow. As i don't have tskip in my settings and i'm at 0,5fps encode speed, i'm not realy enthusiast reducing speed more...
__________________
My github.
jpsdr is offline   Reply With Quote
Old 14th October 2022, 16:53   #18  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,819
Quote:
Originally Posted by jpsdr View Post
Is tskip enabled in slower preset ? (Or in any preset)
Nope, not in any preset (it should be on for placebo at least, IMHO). You can see all the preset parameters here:
https://x265.readthedocs.io/en/master/presets.html

Quote:
Is tskip significant, on 4k HDR 10 bits, on multipass encode, average 40000, maxrate 90000 vbv-buffsize 70000 ?
I doubt it'll make a visible difference at those bitrates. I certainly wouldn't consider using it until I was at least at --preset slower except for very specific content.

Quote:
In any case, from what i've understood, --tskip --tskip-fast will always be better than without tskip, if tskip is realy too slow. As i don't have tskip in my settings and i'm at 0,5fps encode speed, i'm not realy enthusiast reducing speed more...
Tskip won't make things worse, but there is content where it'll burn a lot of CPU without offering appreciable benefit. For example, anywhere there is visible grain.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 14th October 2022, 18:56   #19  |  Link
jpsdr
Registered User
 
Join Date: Oct 2002
Location: France
Posts: 2,330
I am at preset slower with the bitrate i've told, so according your answer it will probably not make a visible difference. When your encode take between 10-15 days, and following this thread you realised that, maybe, you've missed an option to increase quality, you're very... (don't know how to translate, anyway) after having allready done around 3-4 files...
But according your answer, it seems that i didn't miss so much, going a little more...
As i denoised/degrain (so i'm not in the "bad case"), i, out of curiosity, when my encode will finish, make a quick test to see the effect on the speed.
__________________
My github.
jpsdr is offline   Reply With Quote
Old 15th October 2022, 21:58   #20  |  Link
tormento
Acid fr0g
 
tormento's Avatar
 
Join Date: May 2002
Location: Italy
Posts: 2,616
What is the difference between tskip and tskip-fast? Why they can be used together? What will happen?
__________________
@turment on Telegram
tormento is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 22:00.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.