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joelovesapple

macrumors 6502a
Original poster
Sep 25, 2006
773
56
UK
... will these technologies be compatible with my hardwares in High Sierra? I am more concerned about the rMBP if I am honest.

Thanks in advance. (I know I am ok for general OS compatibility).
 

EugW

macrumors G5
Jun 18, 2017
14,086
11,850
macbook pro from 2015, no. imac from 2015, yes for hevc.
But only partially for the 2015 iMac. No hardware 10-bit HEVC decode on those 6th gen Skylake Intel processors.

http://alex4d.com/notes/item/notes-on-apple-hevc-and-heif-from-wwdc17

hevc2.jpg
 

RoboWarriorSr

macrumors 6502a
Feb 23, 2013
889
52
Does this mean Apple is not implementing the hybrid decoding supported on Broadwell processors? Intel's ark and their slide shows for Broadwell does indicate some support for HEVC decoding to minimize CPU usage.
 

EugW

macrumors G5
Jun 18, 2017
14,086
11,850
Does this mean Apple is not implementing the hybrid decoding supported on Broadwell processors? Intel's ark and their slide shows for Broadwell does indicate some support for HEVC decoding to minimize CPU usage.
I guess not. Furthermore, Apple doesn't seem to be using hybrid decoding for Skylake for 10-bit HEVC either. However, I wonder just how effective hybrid decoding really is though. Here's a 10-bit HEVC file being decoded using hybrid on Skylake and full hardware on Kaby Lake (in Windows):

kbl-hevc.png


For Kaby Lake, the CPU usage is around 10%, or usually less, because it's full hardware decoding. For the exact same file on Skylake, it's 40-55% with hybrid decoding.

https://www.pcper.com/reviews/Proce...ng-Jump-over-Skylake/Battery-Life-HEVC-Playba
 
Last edited:

RoboWarriorSr

macrumors 6502a
Feb 23, 2013
889
52
I guess not. Furthermore, Apple doesn't seem to be using hybrid decoding for Skylake for 10-bit HEVC either. However, it seems to me that hybrid decoding is not really all that useful. Here's a 10-bit HEVC file being decoded using hybrid on Skylake and full hardware on Kaby Lake:

kbl-hevc.png


https://www.pcper.com/reviews/Proce...ng-Jump-over-Skylake/Battery-Life-HEVC-Playba
Hard to say without a graph showing the same skylake processor using only software decoding, but looking at some files I have tested, it does appear to improve CPU usage to a least prevent frame skips.
 

EugW

macrumors G5
Jun 18, 2017
14,086
11,850
Hard to say without a graph showing the same skylake processor using only software decoding, but looking at some files I have tested, it does appear to improve CPU usage to a least prevent frame skips.
Fair enough. (I did change my post slightly before you posted yours though.) In your tests, how much CPU usage has it saved? What hardware? Just curious.

Am I correct you are talking about Windows? Or are you using some third party software that enables hybrid decode on macOS?
 

RoboWarriorSr

macrumors 6502a
Feb 23, 2013
889
52
Fair enough. (I did change my post slightly before you posted yours though.) In your tests, how much CPU usage has it saved? What hardware? Just curious.

Am I correct you are talking about Windows? Or are you using some third party software that enables hybrid decode on macOS?
On windows as I am unaware if mpv or any other video player use the hybrid decoding feature on MacOS. Manually updating Intel drivers under windows suggest support for hybrid decoding on software that have HW decoding for HEVC built in. On my 2015 MBP 13", the software update improves frame rate for HEVC on a Russian benchmark test ~10-20 FPS for 10 or 20 MBps IIRC. However this appears to be the sweet spot as the advantages don't seem as apparent in higher bitrate.

Granted under Sierra using MPV backend (IINA), a 10 bit 1080p HEVC file (~12 GB) uses around 40-60% CPU with minimal frame rate drops so I'm not too worried about the lack of hybrid decoding as it seems the high single threaded performance compensates for the lack of hardware decoding.
 

Superhai

macrumors 6502a
Apr 21, 2010
723
527
I don't know if it is able to leverage any hardware, but on my rMBP 2014, quicktime renders HEVC movies much more fluent and without going straight to high fan immediately than what is when played with VLC.
 
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RoboWarriorSr

macrumors 6502a
Feb 23, 2013
889
52
I don't know if it is able to leverage any hardware, but on my rMBP 2014, quicktime renders HEVC movies much more fluent and without going straight to high fan immediately than what is when played with VLC.
In one of the drivers updates, intel indicates hybrid decoding support or at least better utilization of hardware on Haswell machines to playback HEVC. Not sure if Apple added this or found a better way to minimize CPU usage playing back HEVC on older hardware.
 
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