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With the arrival of iOS 11 and macOS High Sierra, Apple is supporting a new video format called HEVC, which replaces the previous standard most commonly used on Mac and iOS devices, namely H.264 / AVC. So why has Apple adopted the HEVC format, and what difference will it make to the end user?

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What is HEVC?

High Efficiency Video Coding (HEVC), also known as H.265, is a next-generation video compression standard developed by a group of encoding experts called the Joint Collaborative Team on Video Coding. The HEVC video format has been in existence since around 2013, and HEIF is the still-image version of the standard that both iOS 11 and macOS High Sierra also support. (You can learn more about HEIF here.)

Benefits of HEVC

Apple's decision to adopt HEVC basically means two things - higher quality video and better compression rates. The HEVC standard enables a video to be compressed into a file that is about half the size (or half the bit rate) of H.264 / AVC. To put that another way, a HEVC video file offers significantly better visual quality than an AVC file of equivalent size or bit rate. While results vary depending on the type of content and the encoder settings, videos encoded in HEVC typically exhibit fewer compression artifacts and offer smoother playback than videos encoded using AVC.

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According to Apple, HEVC can compress 4K video files to up to 40 percent smaller file sizes than AVC without losing quality, which means users who upgrade their devices to iOS 11 and macOS High Sierra will be able to take the same high-quality videos without using up as much storage space. At the same time, transferring high-resolution video files between devices and over networks will require significantly less bandwidth, a key advance considering new 4K iTunes content launched for the new Apple TV 4K.

Compatibility and Support

To capture and encode video in the HEVC format, iOS devices need to have at least an A10 Fusion processor, so owners of iPhone 7 or later and 2017 iPad Pro are fully able to take advantage of the standard. To check if your device's camera is capturing video in HEVC, go to Settings -> Camera -> Formats, and ensure the "High Efficiency" option is selected.

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All iOS devices running iOS 11 and all Macs on High Sierra will support HEVC playback, with encoding/decoding hardware acceleration on newer iOS devices and the latest 2017 Macs offering faster performance combined with less battery drain. Readers interested in further transcoding details are advised to watch Apple's dedicated HEVC codec video presentation.

Article Link: What You Need to Know About HEVC Video in macOS High Sierra and iOS 11
 
Comon, you guys could have put more work in to this.

No info on how High Sierra handles HEVC, hardware acceleration? Which Mac's support it etc?

If your Mac runs High Sierra, then it supports HEVC playback, as noted. Transcoding performance depends on a range of software / hardware factors.
 
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Curious if its worth converting MP4 H264 to HEVC? And I guess you can do that through Handbrake?

I try to have all my videos H264 so it can stream on all devices through plex the best
 
So....if I read the article correctly, my iPhone 6+ with iOS 11 will not be able to capture/encode HEVC but will be able to play HEVC vids, albeit at a lesser efficiency than, say, an iPhone 8 or X. And if I install High Sierra on my late-2011 MBP (assuming it’s supported), I will be able to capture *and* play HEVC vids, but also at lesser efficiency?
 
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If your Mac runs High Sierra, then it supports HEVC playback, as noted. Transcoding performance depends on a range of software / hardware factors.

Hardware HEVC 265 is only supported on mac with Kaby lake procesors

Thanks.

Curious if its worth converting MP4 H264 to HEVC? And I guess you can do that through Handbrake?

I try to have all my videos H264 so it can stream on all devices through plex the best

Only if you have the new processors. I noticed my Mac mini struggles keeping up with HEVC files with a single high quality HEVC file taking up 100% easily
 
The HEVC standard enables a video to be compressed into a file that is about half the size (or half the bit rate) of H.265 / AVC.
@timmyh Small typo. It should read: size (or half the bit rate) of H.264 / AVC. HEVC is H.265.:)
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Blame YouTube/content producers. Most upload in 1080p at best, so YouTube chose to restrict streaming to that.
That's wrong and irrelevant. 4K content is broadcast using VP9.
 
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Looking at that presentation, while anything that supports the respective OSes supports HEVC and HEIF in software, the A9 (and later) support hardware decoding of HEIF and HEVC in both 8 and 10 bit, so the iOS devices with hardware support are:

iPhone 6S and later
iPad 2017
All iPad Pros

For Macs, the 6th gen Core series (Skylake) supports HEIF and HEVC 8-bit decoding in hardware, and the 7th gen (Kaby Lake) also support HEVC 10-bit decoding in hardware, so:

Late 2016 MBP (8-bit video only)
Mid 2017 MBP
Late 2015 iMac, 27" only (8-bit video only)
Mid 2017 iMac, 21.5" and 27"
Early 2016 Macbook (8-bit video only)
Mid 2017 Macbook

I'm assuming here that the m3 in the Macbooks supports it at the same processor generation as the i5/i7 series, although I didn't find any documentation of that in a quick search.
 
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So....if I read the article correctly, my iPhone 6+ with iOS 11 will not be able to capture/encode HEVC but will be able to play HEVC vids, albeit at a lesser efficiency than, say, an iPhone 8 or X. And if I install High Sierra on my late-2011 MBP (assuming it’s supported), I will be able to capture *and* play HEVC vids, but also at lesser efficiency?

Yes and yes.
 
Hardware HEVC 265 is only supported on mac with Kaby lake procesors

10 Bit HEVC HW Decode is supported only by Kaby Lake, Skylake+ MBP supports 8 Bit HEVC HW Decode which supported iPhones encode in.

Further, 10 Bit HEVC is supported in Windows on Skylake MBP w/ AMD Pro using dGPU, but of course that means nothing for the Mac OS side. Just saying its possible.
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and the 7th gen (Kaby Lake) also support HEVC 10-bit decoding in software, so:

Hardware.
 
Decoding performance/efficiency for h.265 from best to worst is:

Full Hardware decoding
Partial reuse of h.264 hardware + GPGPU (Metal or OpenCL)
GPGPU (Metal or OpenCL)
CPU only (ideally with AVX/AVX2 on Macs that support it)

I'm curious how Apple's software decoding fallback for h.265 works? Ideally they'd be doing partial reuse of h.264 hardware + GPGPU (Metal or OpenCL), but they need to do individual solutions to support the hardware h.264 decoder in each IGP/GPU which seems unlikely. So I'm hoping for OpenCL-based GPGPU which probably gives up a bit of performance compared to Metal GPGPU, but would support more Macs. However, I'm guessing software decoding truly means CPU only.
 
I'll probably continue using H.264 AVC for my 1080p/60 videos for the improved compatibility and H.265 HEVC for my 4K/60 videos for the necessary compression (once I get my next iPhone, maybe the X).
 
Decoding performance/efficiency for h.265 from best to worst is:

Full Hardware decoding
Partial reuse of h.264 hardware + GPGPU (Metal or OpenCL)
GPGPU (Metal or OpenCL)
CPU only (ideally with AVX/AVX2 on Macs that support it)

I'm curious how Apple's software decoding fallback for h.265 works? Ideally they'd be doing partial reuse of h.264 hardware + GPGPU (Metal or OpenCL), but they need to do individual solutions to support the hardware h.264 decoder in each IGP/GPU which seems unlikely. So I'm hoping for OpenCL-based GPGPU which probably gives up a bit of performance compared to Metal GPGPU, but would support more Macs. However, I'm guessing software decoding truly means CPU only.

GPGPU is useless for encoders/decoders. And that's why every GPU contains an asic for video codecs.
 
So....if I read the article correctly, my iPhone 6+ with iOS 11 will not be able to capture/encode HEVC but will be able to play HEVC vids, albeit at a lesser efficiency than, say, an iPhone 8 or X. And if I install High Sierra on my late-2011 MBP (assuming it’s supported), I will be able to capture *and* play HEVC vids, but also at lesser efficiency?

The answer is 'yes' and 'no'. A screenshot from my 15 inch late 2013 rMBP running High Sierra. The 'unsupported format' is a 4K 60 fps HEVC video.
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All iOS devices running iOS 11 and all Macs on High Sierra will support HEVC playback, with encoding/decoding hardware acceleration on newer iOS devices and the latest 2017 Macs offering faster performance combined with less battery drain. Readers interested in further transcoding details are advised to watch Apple's dedicated HEVC codec video presentation.

Article Link: What You Need to Know About HEVC Video in macOS High Sierra and iOS 11

I know my 15 inch late 2013 MBP with Retina display does not support the format in higher frame rates even on High Sierra. The 'unsupported format' video on the screenshot is a 4K 60 fps HEVC video. The app is Photos.
 

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