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#8643 | Link | |
Registered User
Join Date: Jul 2015
Posts: 847
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Quote:
I turn on basic SIMD X265. #define ARCH_X86_64 #define HAVE_SSE3 #define HAVE_SSSE3 #define HAVE_SSE4 The rest of the AVX2 and AVX512 are probably default. ARCH_X86_64 && cpuflag(avx512) |
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#8647 | Link | ||
Broadcast Encoder
Join Date: Nov 2013
Location: Royal Borough of Kensington & Chelsea, UK
Posts: 3,180
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You can enable any asm with the --asm command, like:
Code:
--asm avx512 Code:
--asm avx Code:
--no-asm Quote:
Things are of course different in perfectly cooled down server rooms. Quote:
This of course doesn't apply to server rooms where temperature and humidity is perfectly controlled and CPUs can keep a high enough clock under pressure like it happens with my encodes. This is the situation while encoding a MJPEG2000 4:4:4 12bit HDR PQ IMF with x265 to create a consumer H.265 file (with AVX-512 enabled): ![]() ![]() ![]() as you can see, clock fluctuates a bit, but given that the overall temperature of the server room is really low, the CPU is able to keep working at regime under sustained pressure and in this case AVX-512 really make sense, which is why they're enabled in all my workflows. If it wasn't for the wide user-driven community and the open source nature of the project, I would argue AVX512 should be enabled by default just like other intrinsics, 'cause for companies it makes a whole lot of sense... |
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#8648 | Link | |
Lost my old account :(
Join Date: Jul 2017
Posts: 352
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Quote:
2,6Ghz looks rather good for 28C xeon under avx512 load. Mind sharing the frequency when you run x265 without it and the performance Numbers? Cause i also have some systems with Cascade Lake Refresh Xeons and i lost 5-10% when using avx512. Edit. You pipe avs to x265 right? How CPU intesive is that script? How much of the load does the x265 process account for? Last edited by excellentswordfight; 19th October 2022 at 23:33. |
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#8649 | Link | |
Big Bit Savings Now !
Join Date: Feb 2007
Location: close to the wall
Posts: 1,841
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Quote:
Here on a i9-11900K notebook ("14nm", 70nm gate pitch, 125W, 5,3GHz single core turbo, 8 core steady 4,5GHz) I remember to have seen like +10 to +20% x265 fps gain invoking x265 -avx512. Sustained AVX512 CPU clock was above 4GHz, downclocking was avoided with 2 fans running full 4800rpm. Nice to have, and I will stay there, but not worth a bigger fuss. Will have to repeat a test encode and note down my comparison. Now in 2022 a "5nm" (in reality 51nm gate pitch) CPU (AMD) will be the better investment, I guess.
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#8651 | Link | |
Registered User
Join Date: Jul 2007
Posts: 63
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#8652 | Link | |
Registered User
Join Date: Mar 2007
Posts: 103
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#8653 | Link | ||
...?
Join Date: Nov 2005
Location: Florida
Posts: 1,458
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Quote:
There is this build script that handles several things - including the Apple patch - for building FFmpeg: https://github.com/Vargol/ffmpeg-apple-arm64-build. As an aside, the 'avisynth' branch on that repo confuses me, because it's up-to-date with the master branch and has no additional changes, and the master branch doesn't have it enabled, even though that's fully possible. Quote:
https://en.wikipedia.org/wiki/AVX-512#Performance https://en.wikipedia.org/wiki/Advanc...s#Downclocking AVX downclocking was present as actual modes in several generations, based on the width of the executed instructions. To wit, GCC and Clang prefer a vector width of 256 when using AVX-512, which would largely sidestep the issue. From the snippets I've read on the topic, this also seems to be the way Zen4 implements AVX-512 in hardware. Skylake had three levels, Ice Lake had only two. But as of Rocket Lake, those explicit downclocking modes are gone. AVX-512 will not downclock on modern generations just because 512-wide vectors get used, but only because doing so may or may not hit standard thermal or power limits, same as any other intensive process. |
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#8654 | Link | |
Moderator
![]() Join Date: Jan 2006
Location: Portland, OR
Posts: 4,956
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Quote:
I'd still like to get a separate x265 binary not in ffmpeg so I can use identical syntax across platforms, but this is certainly enough for perf testing. |
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#8655 | Link |
Registered User
Join Date: Mar 2007
Posts: 103
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x265 master branch already contains the Apple intrinsics patches, plus a lot of additional Neon optimizations provided by Amazon. No need to look for weird forks or branches. But there are still a couple of patches in the HandBrake repository that will make it run better.
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#8657 | Link |
Moderator
![]() Join Date: Jan 2006
Location: Portland, OR
Posts: 4,956
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Wow, x265 got more commits nine hours ago than it got the rest of 2022!
https://bitbucket.org/multicoreware/x265_git/commits/ |
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#8659 | Link | |
German doom9/Gleitz SuMo
Join Date: Oct 2001
Location: Germany, rural Altmark
Posts: 7,175
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Quote:
_ No, there is no fix yet; MABS does not build x265 anymore. Last edited by LigH; 22nd October 2022 at 16:42. |
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#8660 | Link |
Registered User
Join Date: Jan 2019
Location: Canada
Posts: 575
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The new SBRC patch forgot to free memory used from edge detection buffers, so it probably leaks when using --sbrc without AQ mode 4.
It's essentially the same as a 2 year old patch for auto-AQ varying by frame average brightness and edge density.
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LG C2 OLED | GitHub Projects Last edited by quietvoid; 22nd October 2022 at 17:28. |
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