Which processor to encode x265 4K ?

[tormento]

Originally Posted by excellentswordfight

4th-gen Epyc, Genoa, is due for release soon as weel and will also feature avx512.

Notice that AMD implementation of AVX512 is a sort of AVX256*2.

I have yet to see the tests.

[tormento]

Originally Posted by excellentswordfight

Thats a win for 7950X, 13900k needs close to 400W be able to push infront of it, in stock its still a bit more power hungry than 7950X.

I am so curious to see a x265 encode with the so called "eco mode" enabled for both.

[Stereodude]

Originally Posted by excellentswordfight

Thats a win for 7950X, 13900k needs close to 400W be able to push infront of it, in stock its still a bit more power hungry than 7950X.

If you're concerned about power efficiency with x265 encoding the 5950X is likely the best choice if your running stock default CPU settings. It's not 2x slower, but uses like half the power of these new CPUs.

[tormento]

Originally Posted by Stereodude

If you're concerned about power efficiency with x265 encoding the 5950X is likely the best choice if your running stock default CPU settings. It's not 2x slower, but uses like half the power of these new CPUs.

Raptor Lake has a 90W mode, Zen4 a 80ish one.

I mean those eco modes.

[hajj_3]

New intel raptor lake looks quite good but they use way more power than the 125w that they claim:

[nevcairiel]

Originally Posted by tormento

Raptor Lake has a 90W mode, Zen4 a 80ish one.

I mean those eco modes.

You can also just input whatever power limit you want to run at, like an actual number.

[Boulder]

Originally Posted by hajj_3

New intel raptor lake looks quite good but they use way more power than the 125w that they claim

That's TDP which is different from the actual power usage.

[DMD]

Originally Posted by excellentswordfight

Of the big review sites I think that techpowerup does the best x265 test (using preset slow and crf 20), so I would check there once its reviewed.

https://www.techpowerup.com/review/a...-7950x/17.html

Thank you.
I need to evaluate the trade-off between performance and power dissipation.
For Ryzen 95°C is a very high temperature, especially for a processor built on the 5 nm node,
that's what I read.
https://www.techpowerup.com/review/a...al-throttling/

[Boulder]

From what I know, AMD went all-in with performance and the power usage (= heat) part was neglected. I think quite a few tests have been made and if you lower the PPT limit in PBO, you get almost the same performance for much less consumed watts.

Running a proper Curve Optimizer set will lower the power usage even further, but it will take some days to fine tune it. Then you can put some negative core voltage offset as well, it seems. My 5950X runs happily with -0.0825V without any performance degradation, then I did the CO tuning on top of that with many cores going all the way to -30 there.

[DMD]

So you can still act on the core rension parameters to get a good compromise between heat and performance?
Because it was the excessive power dissipation that was worrying me a bit.

[excellentswordfight]

Originally Posted by DMD

Thank you.
I need to evaluate the trade-off between performance and power dissipation.
For Ryzen 95°C is a very high temperature, especially for a processor built on the 5 nm node,
that's what I read.
https://www.techpowerup.com/review/a...al-throttling/

Originally Posted by DMD

So you can still act on the core rension parameters to get a good compromise between heat and performance?
Because it was the excessive power dissipation that was worrying me a bit.

"The biggest problem is probably psychological. For years we have been trained that "95°C is bad". This is no longer true. 95°C is the new 65°C. "

These new processors are designed to boost until they hit these temperatures as long as the power target allows for it if. So wouldnt worry about it.

If you are worried about power dissipation look at the power draw, not the temperature, if a CPU consumes 200W it will dissipates as much heat/energy if it running at 65C as 95C.

And as Boulder mentioned you can limiit the powerdraw on most new processors without much loss i performance. I have PL1 set at 200W (60s duration max) and PL2 at 125W (long time load) on my 12700k, when encoding the performance difference is not big when it dropps down to 125W, and fans goes pretty much silient with air cooler.

[DMD]

Originally Posted by excellentswordfight

"The biggest problem is probably psychological. For years we have been trained that "95°C is bad". This is no longer true. 95°C is the new 65°C. "

These new processors are designed to boost until they hit these temperatures as long as the power target allows for it if. So wouldnt worry about it.

If you are worried about power dissipation look at the power draw, not the temperature, if a CPU consumes 200W it will dissipates as much heat/energy if it running at 65C as 95C.

And as Boulder mentioned you can limiit the powerdraw on most new processors without much loss i performance. I have PL1 set at 200W (60s duration max) and PL2 at 125W (long time load) on my 12700k, when encoding the performance difference is not big when it dropps down to 125W, and fans goes pretty much silient with air cooler.

I thank you for reassuring me.
Then I will consider what kind of dissipation to use , whether fan or liquid (AIO), but that is another topic.

[HD MOVIE SOURCE]

Just wondering, can any cpu encode 2 hours worth of footage in 24 hours or less and use at least very slow with x265?

[hajj_3]

Originally Posted by HD MOVIE SOURCE

Just wondering, can any cpu encode 2 hours worth of footage in 24 hours or less and use at least very slow with x265?

the resolution and bitrate of the source video would be needed to answer that and also the output resolution.

[RanmaCanada]

Originally Posted by HD MOVIE SOURCE

Just wondering, can any cpu encode 2 hours worth of footage in 24 hours or less and use at least very slow with x265?

Quite possibly an 5950x or 7950x with chunking being used. But again it also depends on the resolution and the bitrate, along with any switches. I know my 5800x will take 2-3 days to encode 4k anime at very slow, averaging about 1fps.

[excellentswordfight]

Originally Posted by RanmaCanada

Quite possibly an 5950x or 7950x with chunking being used. But again it also depends on the resolution and the bitrate, along with any switches. I know my 5800x will take 2-3 days to encode 4k anime at very slow, averaging about 1fps.

At 4k I usually get up to 80-100% usage on 24C/48T when leaving thread-affecting switches as default, so I dont think its a necessity to use chunk encoding for 16C models (although it will probably give you a slight speed boost).

With that said, might be possible on a high core count threadripper using chunk encoding. I get about 1fps on a 24C epyc for standard complexity content at veryslow (complexity has a huge impact on speed in these cases). So I dont 7950X is enough to break 2fps.

But if HD MOVIE SOURCE still does encodes at 98Mbps CBR, I dont see any reason of using veryslow in the first place. If the output has visual issues, its not cause slower is used over veryslow.

[benwaggoner]

Yeah, these things can be hard to predict. When using --crf, a clean source like anime can encode a lot faster than a grainy content with the same parameters. Entropy coding is significant, and that's proportional to net bitrate. And getting a good skip match early-exits a whole lot of compute that random noise precludes. Although in the grainy 4K case, --rd 4 can sometimes deliver better quality than the --rd 6 used in --preset slower and above, and it goes quite a bit faster. Reducing --frame-threads often doesn't have that much of a speed impact at high resolutions as the overhead of frame threading makes each thread slower than without frame threading.

Using one of my "Xeon Gold 6240 CPU @ 2.60GHz, 2594 Mhz, 18 Cores, 36 Logical Processors" with my default 4K settings for undefined content tuned for "take more time wherever it makes a potentially visible improvement" does a little more than an hour a day. I'm sure a more modern CPU could do better. 16 cores at a higher clock speed would be a bit faster yet; it seems to use about 12 cores on average, with spikes up and down.

[HD MOVIE SOURCE]

Okay, my assumption is that with x265 encoding we're talking about content that is 4K, but I should have made that clear. So, what kind of CPU would be needed for 24 to 48 hour encode, with a 2 hour movie, and if you need bit-rate, my target bit-rate would be 98 Mbps, just like 4K UHD-BD.

[benwaggoner]

Originally Posted by HD MOVIE SOURCE

Okay, my assumption is that with x265 encoding we're talking about content that is 4K, but I should have made that clear. So, what kind of CPU would be needed for 24 to 48 hour encode, with a 2 hour movie, and if you need bit-rate, my target bit-rate would be 98 Mbps, just like 4K UHD-BD.

With that bitrate, you can target a lot higher performance without visual loss. With --vbv-maxrate 98000, a simple --crf 14 --preset medium should be pretty well transparent.

Making 4K look good with a 10 Mbps peak is a lot harder, which is where extra tools with extra performance implications kick in. Throwing 9.8x more bits at the problem means the encoder starts out with much, much lower QPs, which is the classic brute force way of improving quality.

[excellentswordfight]

Originally Posted by HD MOVIE SOURCE

Okay, my assumption is that with x265 encoding we're talking about content that is 4K, but I should have made that clear. So, what kind of CPU would be needed for 24 to 48 hour encode, with a 2 hour movie, and if you need bit-rate, my target bit-rate would be 98 Mbps, just like 4K UHD-BD.

As its seems like you are ignoring a lot o the answers provided to you, but im gonna give it a lost shot.

First of all I answered your CPU question above, with high complexity 4k material no CPU on the market is likely to break 2fps at veryslow, it can be done with chunk encoding if you go for something like a Threadripper 5975WX or 5995WX, if go above the 24h requirement something like a 7950X will probably get you there without chunkencoding, I will guestimate that you might get close to 2fps for preset veryslow.

Secondly, the gains of presets like veryslow are very much in the diminishing returns territory, and when we are talking about such high bitrates its even beyond overkill imo. As I said, if you have issues with the output at 98Mbps at something like slow or slower, I would look at other parameters then going to preset veryslow. All uhd-bluray encodes ive done has been visually lossless at slow and slower at much lower bitrates.

Its still very unclear what the goal is here, complying to the uhd-bd specifications are only limitations, there is no real reason to use those unless you really are authoring for actual physical discs. If the reason is of more academic purpose, I still dont really understand it given the abnormal avrage bitrate that doesnt really have any real world application. Cause again "98Mbps" is not "UHD-BD", the specifications mandates a max bitrate of 100Mbps, and the average bitrate will be based on the size constrains of the physical medium. Close to zero titles will actually have a avrage bitrate that high, so its nothing that represent the uhd-bd format, and a part form that setting 98Mbps togheter with something like 98 for vbv-limitis that you need to have a uhd-bd compliant encode you are pretty much doing CBR-encoding that can have some bitrate distribution sideeffects that could actually hurt quality.

If the interest is more a question of what getting the absolute max out of x265 (i.e. using all the tools in the kitchen sink without caring to much of the practicality of the encoding speed) it makes so much more sense to try to find the limit were it becomes visually transperent instead of just setting a huge abr were most tuning and cpu-consuming tools just becomes irrelevant.