x265 HEVC Encoder

[benwaggoner]

Originally Posted by jlpsvk

it's better to use --aq-mode 2 or --aq-auto 6 for 4K HDR? both giving me almost same bitrate at CRF16 with preset slower (with some manual settings)

--aq-mode 2 is pretty optimal for 4K HDR encoding. The --aq-auto might be just picking that mode repeatedly, hence not much of a bitrate difference. Have you checked visually?

[redbtn]

Originally Posted by benwaggoner

--aq-mode 2 is pretty optimal for 4K HDR encoding. The --aq-auto might be just picking that mode repeatedly, hence not much of a bitrate difference. Have you checked visually?

Do you still recommend using --aq-mode 2 over --aq-mode 4 for 4K HDR?
I use --aq-mode 4 for SDR, but not sure about HDR.

[benwaggoner]

Originally Posted by redbtn

Do you still recommend using --aq-mode 2 over --aq-mode 4 for 4K HDR?
I use --aq-mode 4 for SDR, but not sure about HDR.

I use --aq-mode 4 for SDR and --aq-mode 2 for HDR.

[ShortKatz]

I recently started to use --aq-mode=4 for everything. It has been said --aq-mode=4 is for "videos with high edge contents (Ex: Ducks take off, Crowd run, Raindrops etc)". (1) And because this can happen in every video, I use 4 now with every kind of video. I've noticed that the encoding time is reduced for --aq-mode=4 compared to --aq-mode=2. I also visually like the result better (HDR and SDR).
(1) https://www.mail-archive.com/x265-de.../msg11661.html

[benwaggoner]

Originally Posted by ShortKatz

I recently started to use --aq-mode=4 for everything. It has been said --aq-mode=4 is for "videos with high edge contents (Ex: Ducks take off, Crowd run, Raindrops etc)". (1) And because this can happen in every video, I use 4 now with every kind of video. I've noticed that the encoding time is reduced for --aq-mode=4 compared to --aq-mode=2. I also visually like the result better (HDR and SDR).
(1) https://www.mail-archive.com/x265-de.../msg11661.html

In extensive testing, I found --aq-mode 2 to be slightly better overall compared to 4 for CVBR encoding of premium 24p HDRcontent, given a number of other parameters that were also used. But certainly 4 is probably better for some content and/or parameter combinations. The real comparison should probably be between the modes both with their own optimal --aq-strength, as generally --aq-mode 4 tends to be optimal with somewhat lower strengths than the other modes.

It's also possible that the --auto-aq mode isn't optimally tuned for HDR content; I've not tested with the feature myself.

[ShortKatz]

Yes, I still need to find the optimal --aq-strength. This will probably take some time.

[benwaggoner]

Originally Posted by ShortKatz

Yes, I still need to find the optimal --aq-strength. This will probably take some time.

And aq-strength is pretty content dependent, lower for cel animation and high grain, higher with cleaner natural images and CGI.

[ksks]

Hello,
I noticed that a trouble took place when someone was trying to use --rd-refine in order to encode videos with better quality and smaller size. I wonder if that could been solved as they thought.

https://bitbucket.org/multicoreware/...glitch-in-some
https://github.com/Mr-Z-2697/x265-Yu...ment-103498859

[benwaggoner]

I just noticed today is the 2nd anniversary of x265 3.5.

We've never had even a one year gap from releases before now. I hope a 3.6 is coming before long. There have been quite a few new features and fixes it would be nice to have in a official build.

[Barough]

Originally Posted by benwaggoner

I just noticed today is the 2nd anniversary of x265 3.5.

We've never had even a one year gap from releases before now. I hope a 3.6 is coming before long. There have been quite a few new features and fixes it would be nice to have in a official build.

It's been very slow going with x265 for sometime now. I sure do hope for v3.6 in a near future.

[ShortKatz]

Yes, the development of x265 has become really slow. My guess is that MCW is focusing more on x266 at the moment and therefore neglecting x265.

[~ VEGETA ~]

I have ryzen 7900x cpu with nvidia rtx 3060ti, which version should i use? what is the best website to get these up to date binaries from?

also, any specific cli commands regarding my cpu which can increase performance?

[LigH]

The GPU does not matter at all for x265.

The CPU supports AVX2 which any x265 build for an intel/AMD compatible CPU will detect and use automatically. It also supports AVX512 what you would have to enable by a command line parameter, but it will heat up the CPU a lot more and may get its clock rate throttled, so it may be faster or not, but will be a risk for reliability.

The most important core functions of x265 have CPU optimizations in several variants. There are also builds out there which are further optimized in rarely used functions, so their gain will probably be negligible. It is probably much more important to find a sane balance between multithreading of prefiltering (in AviSynth or VapourSynth or whatever conversion system you prefer) and multithreading in x265, to utilize all the cores without severe bottlenecks.

[Lan4]

Tell me the best x265 build for a processor with AVX only. Or similarly, build doesn't matter, they all work the same way?

[LeXXuz]

I have an argument with someone.
If I increase aq-strength, do high motion areas/scenes get more or less bits?

[benwaggoner]

Originally Posted by LeXXuz

I have an argument with someone.
If I increase aq-strength do high motion areas/scenes get more or less bits?

What aq-strength does is baed on the --aq-mode being used. Generally aq-modes are about preventing blurring in smoother areas caused by more naive PSNR or SAD type metrics. In general x265 will spend fewer bits on areas of high motion that aren't good references for frames later in the GOP; --cutree is the main tool to identify those. This results in adaptive quantization, absolutely, but not directly controlled by --aq-mode or --aq-strength. I'm sure there are some interactions in practice, as all kinds of things can change how x265 allocates bits.

[benwaggoner]

Originally Posted by Lan4

Tell me the best x265 build for a processor with AVX only. Or similarly, build doesn't matter, they all work the same way?

That is going to be some old hardware. It wouldn't take that many compressed titles before it'll be cheaper on electricity to buy a newer, faster, and much more efficient CPU. The fastest pre-AVX CPU probably will have <10% the throughput of a modern enthusiast chip, which will have many more cores, AVX2, and overall better instructions per clock.

[Lan4]

Originally Posted by benwaggoner

That is going to be some old hardware. It wouldn't take that many compressed titles before it'll be cheaper on electricity to buy a newer, faster, and much more efficient CPU. The fastest pre-AVX CPU probably will have <10% the throughput of a modern enthusiast chip, which will have many more cores, AVX2, and overall better instructions per clock.

Buying a new processor is too easy. And for the purchase of a processor, you will need a new motherboard, new memory, a new power supply. Still, my question was about the x265 codec.

[Boulder]

Originally Posted by Lan4

Tell me the best x265 build for a processor with AVX only. Or similarly, build doesn't matter, they all work the same way?

They work the same way, the encoder uses the instruction sets that are detected.

You might get some performance benefits from compiling the executable with specific tuning for your CPU. Media Autobuild Suite can do this, there is a possibility to tweak the compiler parameters accordingly (-march and -mtune in specific).
https://github.com/m-ab-s/media-auto...nal-user-files

[LigH]

Just committed:

[PATCH] Fix bug in mcstf

Building...