x265 HEVC Encoder

[LigH]

Originally Posted by jlpsvk

No... x265 ... 5 instances at once (RipBot264 Distr. encoding) to penetrate all cores at 100%.

This requires a powerful fan ...

[jlpsvk]

Originally Posted by LigH

This requires a powerful fan ...

Nope... Noctua NH-D15 keeping it at 63 degrees.

[Loomes]

Originally Posted by jlpsvk

Nope... Noctua NH-D15 keeping it at 63 degrees.

That's great but what is your frequency and your AVX offset? Because that's what makes the heat.

[jlpsvk]

Originally Posted by Loomes

That's great but what is your frequency and your AVX offset? Because that's what makes the heat.

All 14 cores running at 3.7GHz (instead of 3.1 stock).

[RieGo]

Originally Posted by jlpsvk

All 14 cores running at 3.7GHz (instead of 3.1 stock).

so no AVX512 offset?

i got really weird results while using avx512 and x265:
A) temps don't really go much higher while using avx512, at least on my system
B) AVX512 offset almost doesn't make a difference. i had same performance on 12x 100MHz difference in offset

[Asmodian]

Are you sure you are using AVX-512 and not bottlenecked by something else? I could notice even 2x offset (200 MHz), not hugely significant but a reproducible decrease in performance. Temperatures weren't much, if any, higher for me, running AVX2 or AVX512.

If you use something like hwinfo do you notice any cores running at the offset multiplier?

[Ma]

Originally Posted by Loomes

Are you using ffmpeg?

In case that the bug is in ffmpeg instead of x265, you can test ffmpeg binaries compiled by VS2015 -- ffmpeg-20180424.7z (without any libs, only for decoding video). I've added also ffmpeg compiled by GCC 7 and GCC 8 with only '-O2' optimize option instead of default '-O3 -fno-tree-vectorize'.

In my Win10/i7 8700 all 3 ffmpeg binaries works (and current Zeranoe builds also works).

[Loomes]

Originally Posted by Ma

In case that the bug is in ffmpeg instead of x265, you can test ffmpeg binaries compiled by VS2015 -- ffmpeg-20180424.7z (without any libs, only for decoding video). I've added also ffmpeg compiled by GCC 7 and GCC 8 with only '-O2' optimize option instead of default '-O3 -fno-tree-vectorize'

Thanks a lot, I will do some more tests at the weekend. I have a feeling that it's not x265 or ffmpeg but that there's something wrong with my system. At least my Win10 install is rather fresh, almost vanilla and from an ISO directly downloaded from the Microsoft site. Well, I'll find out!

[sdml]

Am I correct that all *-refine-* features useful only for multi-pass scenarios?

[froggy1]

Originally Posted by sdml

Am I correct that all *-refine-* features useful only for multi-pass scenarios?

rd-refine works in crf too

[Boulder]

I'm a bit confused as Bhavnahari stated that "refine-inter and refine-intra features may be used with any rate control techniques including ABR, CRF and CQP". Why would you do a 2-step encode in CRF mode to utilize the refining? Shouldn't a normal CRF encode already bring all the quality you can get from your settings with the least amount of time spent on encoding or analysing?

[Asmodian]

I believe the point is to do much of the analysis on a lower resolution video, then reuse that analysis with the higher resolution while still doing some refinement to fine tune the analysis for the full resolution. This gives a speed boost while also not lowering the quality too much, like simply using the analysis done on the low resolution video directly would.

I am not sure I would do this, but then I tend to run far up the quality/speed curve, e.g. preset veryslow with a few extra options that slow it down even more. It would be interesting to see the speed and quality impacts from using this method compared to slower or faster presets and/or other options.

[WhatZit]

Originally Posted by Asmodian

I believe the point is to do much of the analysis on a lower resolution video, then reuse that analysis with the higher resolution while still doing some refinement to fine tune the analysis for the full resolution.

Basically correct. The idea is to "Analyse once, encode many".

Many of the recent CLI functions added to x265 are there to suit the demands of professional broadcast/OTT content providers, who may wish to create multiple resolution and bitrate copies of any one source.

The practical consumer application of this particular "reuse" functionality would be very niche.

[jlpsvk]

Originally Posted by RieGo

so no AVX512 offset?

i got really weird results while using avx512 and x265:
A) temps don't really go much higher while using avx512, at least on my system
B) AVX512 offset almost doesn't make a difference. i had same performance on 12x 100MHz difference in offset

probably Intel is OC-ing itself as it has good thermal conditions. temps with AVX-512 are bit lower in fact on my system.