HEVC hardware decoding on iMac 27" late 2015

EnesM

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May 7, 2015
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Can anyone confirm if AMD 395 can hardware decode HEVC (H.265) codec?

I know that Skylake processor are supposed to that as well although not all profiles.
 

florinbss2

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Oct 30, 2015
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There can be no HEVC decoder card from AMD. The only video card that can be geforce 960 and 950
 

Sirmausalot

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Sep 1, 2007
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i think it is the skylake igpu, not the cpu that has a dedicated h265 decoder. so we will see that with the next round. of course it can be decoded with the cpu, just not sure how efficent it is.
 

EnesM

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i think it is the skylake igpu, not the cpu that has a dedicated h265 decoder. so we will see that with the next round. of course it can be decoded with the cpu, just not sure how efficent it is.
So does iMac have the igpu as well, like all the macbooks, but it doesn't use it?
 

loekf

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Mar 23, 2015
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I thought e.g. Handbrake uses Quicksync (= Intel HW decode and encoder in the on-chip GPU) if present. So depending on OSX drivers etc. Late 2015 models might do hardware accelerated x265. Did you check the console output/logging of Handbrake ? You might need a nightly.
 

joema2

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i think it is the skylake igpu, not the cpu that has a dedicated h265 decoder...
I think Quick Sync uses on-chip resources associated with the integrated GPU but actual decoding is not handled by the GPU per se. Rather Quick Sync is more like an ASIC that does encode/decode, but as implemented it needs the iGPU to be present.

In general GPUs cannot productively accelerate encode/decode of long-GOP codecs like H264 or H265. It is a fundamental limitation due to the sequential nature of the core algorithm and data dependencies which prevent leveraging GPU-style parallelism. There are dozens of academic white papers where researchers have unsuccessfully tried to use GPU acceleration on H264. The X264 team got some limited GPU benefit in certain cases and some versions of Handbrake have this. However it was not a huge increase like Quick Sync.

The Quick Sync on Skylake was supposedly enhanced to do H265 and VP9 but I haven't see any test of this. It would be more important for H265 than H264 since the new codec is so compute intensive.
 

EnesM

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Exactly, it's h265 that worries me, h264 is a piece of cake nowadays, whereas h265 is what h264 was 5 years ago, really heavy on the CPU
 

HEVC

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Nov 16, 2015
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So, here I am, testing brand new Late 2015 iMac MK482LL/A, $2,299 USD retail. This is the top standard (not customized) config offered by Apple; with 27" 5K, Skylake i5/3.3-3.9GHz, 8GB RAM, 2TB Fusion, AMD Radeon R9 M395.

I’m trying to open several HEVC (x265) 4K (2160p) sample movie trailers in MP4 format; each about 300-500 MB in size, 1-2 minutes in length. My Windows machine with MPC-HC video player plays these trailers with no problems.

On iMac, Apple QuickTime Player would not open any of these files. Same result with DivX player. VLC opens all of trailers fine, but plays extremely choppy and unwatchable video, at the same time overloading all 4 CPU cores 100%. I’m going through VLC settings, trying to force hardware decoding, however still get the same very choppy video and CPU overload.

Intel specifies that Skylake does support HEVC hardware decoding; but Skylake integrated graphics output is limited to 4K resolution. So, apparently iMac 5K uses discrete AMD graphics for all its video playback tasks. Alas, AMD R9 M395, as well as all other AMD GPUs except the newest Fury line, do not support hardware HEVC decoding.

Here we go. Apple built 5K super-duper iMac with extended DCI-P3 colour gamut, especially targeted for film creation and playback. And Apple "forgot" to add both hardware acceleration and native software support for HEVC, which is the industry standard for 4K video codec.

Among other things, HEVC is the codec for all 4K Blu-ray disks that will hit shelves en masse in 2016; but 5K iMacs would not be able to play 4K Blu-rays. Unless, of course, you spend another $2,299 to buy the newest next year’s iMac, which hopefully will support HEVC.

Bravo, Apple!
 

Sirmausalot

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Sep 1, 2007
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H265 is far from a standard. The only camera that shoots in it is from Samsung and they are getting out of the camera business. Mac hasn't supported blue ray, ever. It will support streaming 4k. Physical media is dead and no real world filmmaker uses h265. Maybe in a few years, but not now. So it is hardly a failure on Apple's part not to support something no one really uses.
 

joema2

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Intel specifies that Skylake does support HEVC hardware decoding; but Skylake integrated graphics output is limited to 4K resolution. So, apparently iMac 5K uses discrete AMD graphics for all its video playback tasks.
Video decoding has nothing to do with display resolution. You could theoretically put an Intel CPU with Quick Sync H264 hardware-assisted encode/decode in a computer with an 800x600 screen. It would still use Quick Sync if the software was written properly. Quick Sync on Skylake will provide hardware-assisted encode/decode of 4k H265 or VP9 whenever someone writes the software for this.

...Alas, AMD R9 M395, as well as all other AMD GPUs except the newest Fury line, do not support hardware HEVC decoding.
What does that have to do with your situation? The Fury X is a 375 watt board, which is more than an entire iMac 27. The iMac 27 already has hardware-assisted HEVC encode/decode in the CPU.

....Apple "forgot" to add both hardware acceleration and native software support for HEVC, which is the industry standard for 4K video codec.
As already mentioned this is not that standardized. That is why VP9 is a competing standard to HEVC. Also there is no "native" software support. Each application developer must write to Quick Sync. Some developers like Handbrake and FCP X do, others like Adobe do not.

...5K iMacs would not be able to play 4K Blu-rays.
5K iMacs have no optical disk at all, nor does Apple make a Blu-Ray drive for the iMac, nor will they ever make one. Yes in that sense a 5K iMac will not be able to play a Blu-Ray, 4k or any other type.

In 2016 when 4k Blu-Ray content is supposed to materialize, if someone makes a USB-compatible 4k BRD player, then you could possibly plug that into your iMac and play it. Whether you'd want to watch it is another matter: http://www.theverge.com/2015/11/11/9713580/4k-uhd-blu-rays-announced-release-date

Unless, of course, you spend another $2,299 to buy the newest next year’s iMac, which hopefully will support HEVC
Quick Sync on the Intel Skylake CPU supposedly supports hardware-assisted HEVC decoding now, the issue is does anyone make software to harness this. The chip was just released, so this will take some time.

Quick Sync hardware-assisted H264 encode/decode has been available since 2011, yet Premiere Pro still does not support it. So depending on who the software company is there may be some delay.
 

florinbss2

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Oct 30, 2015
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4K streaming (Netflix) is all h.265. The following films 4k (which will occur in 2016) will be as h.265. Probably the next generation of cameras will film the h.265. So in a year you will miss h.265 hardware on the new iMac and we feel frustrated.
 

Sirmausalot

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4K streaming (Netflix) is all h.265. The following films 4k (which will occur in 2016) will be as h.265. Probably the next generation of cameras will film the h.265. So in a year you will miss h.265 hardware on the new iMac and we feel frustrated.
we already film 4k in many more robust formats than h265 that don't break down at the slightest hint of color grading. and there is no pc that can stream 4k netflix or amazon either. so this is another false argument. apple doesn't need to spend the resources to impliment something for which there is no demonstratable demand. there are no 4k blu ray players his year nor and 4k blu ray burners anywhere near ready for mass market. if i can be done with physical media for distribution, hooray! and if i do need to work with h265, I'll transcode to pro res or another intermediate that is more editnd grading friendly.
 

joema2

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4K streaming (Netflix) is all h.265. The following films 4k (which will occur in 2016) will be as h.265. Probably the next generation of cameras will film the h.265. So in a year you will miss h.265 hardware on the new iMac and we feel frustrated.
My 2015 iMac can play 4k H.265 and VP9 material right now -- I just did it. It took about 1/8th of the iMac's CPU capacity; the NX-1 clip took about 40%. On a capable iMac or PC, you can also download and try playing these modest-size test clips:

4k VP9 (play in Chrome):http://www.reduser.net/forum/showthread.php?111230-Google-VP9-4K-HD-Sample

4k H.265 (play in VLC) : https://x265.com/hevc-video-files/

4k H.265 from Samsung NX-1 (play in VLC): http://www.imaging-resource.com/news/2014/11/19/samsung-nx1-4k-video-samples-and-new-full-res-frame-grabs-available-for-do

The issue with NetFlix and H.265 is *not* a technical one, it is a dispute about copy protection. If it were not for this, my iMac could stream H.265 from NetFlix right now. Until that dispute is resolved, no amount of CPU or GPU hardware will work since it is a legal dispute:

http://www.techhive.com/article/2858474/why-you-cant-get-4k-netflix-and-amazon-on-a-pc-or-mac-even-though-theyre-capable.html

There are two sides to this: content producer/distributor and content consumer. Content producers & distributors are in two sub-categories, large commercial ones (Comcast, NetFlix, etc) and smaller ones.

Large content producers & distributors care about H.265 for both 4k *and* HD because it squeezes twice the data into their distribution pipes. Manufacturers of 4k TVs care because H.265 gives them access to 4k content and a sellable TV upgrade to existing HD TV owners.

As a smaller content producer, whether the next generation of cameras uses H.265 doesn't affect me. As a professional videographer I shoot and edit 4k H.264 nearly every day. That works fine. We have no immediate need for H.265 since none of our viewers could watch it. No mainstream editing software supports direct H.265 editing, so we'd have to transcode. We shoot in 4k H.264 because of the editing advantages, not to distribute in 4k -- we distribute in 1080p.

Content consumer: Because of the above-mentioned legal battle, consumers are greatly restricted in their access to H.265 material. It basically is unavailable from most streaming sites for a PC or Mac. You have to buy a TV. Whenever Blu-Ray 4k becomes available, it is unclear if you'll be able to play that on any PC or Mac due to copy protection issues. This has nothing to do with whether the computer has hardware-accelerated H.265 encode/decode. My 2015 iMac has that right now in the Skylake CPU and it doesn't make any difference in the legal copy-protection battle.

Ironically the least-encumbered pathway to 4k distribution may be Youtube, since Google owns the VP9, the free open-source competitor to H.265.

Here is a detailed discussion and lecture about some of these issues with HEVC/H.265 titled "4K HEVC Video Is Years Away From Being a Streaming Reality": http://www.streamingmedia.com/Articles/Editorial/Featured-Articles/4K-HEVC-Video-Is-Years-Away-From-Being-a-Streaming-Reality-103530.aspx
 
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AppleHater

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What does that have to do with your situation? The Fury X is a 375 watt board, which is more than an entire iMac 27. The iMac 27 already has hardware-assisted HEVC encode/decode in the CPU.
If a codec requires 375 watt GPU and the latest Intel cpu isn't fast enough, in and of itself proves that it's far from ready for mainstream usage.
 

joema2

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If a codec requires 375 watt GPU and the latest Intel cpu isn't fast enough, in and of itself proves that it's far from ready for mainstream usage.
Yes, and to reiterate: the 2015 iMac 27 has hardware-assisted HEVC encode/decode today. The issue is what software supports that, and to what degree that's needed for decode vs encode.

My iMac can *decode* HEVC and VP9 just fine right now -- apparently without hardware support. So as a content consumer, people with a new iMac are all set -- provided the legal issues over HEVC ever get resolved.

As a content producer, encoding 4k HEVC/H.265 is much more demanding. I just tested it in Handbrake and it's about 4-8 frames/sec. It is not apparently using Quick Sync on H.265 which is understandable since Skylake is the first CPU to have H.265 support. This is of limited concern for me since neither Youtube nor Vimeo accept H.265 uploads.

Currently no mainstream editing software supports direct H.265 editing, but virtually no cameras shoot that except the now-cancelled Samsung NX-1. It is unclear which if any cameras will record HEVC/H.265 in the near future: http://www.dtcreports.com/weeklyriff/2015/08/10/hevc-not-winning-camera-converts/

If some camera did, it would likely also support H.264 for backward compatibility. If we got such a camera we'd likely just use H.264. If it *only* did H.265 and if by *then* (likely years off) FCP X still didn't support it, we'd just transcode before import -- just like Samsung NX-1 users did.
 

EnesM

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My 2015 iMac can play 4k H.265 and VP9 material right now -- I just did it. It took about 1/8th of the iMac's CPU capacity; the NX-1 clip took about 40%. On a capable iMac or PC, you can also download and try playing these modest-size test clips:
So, here I am, testing brand new Late 2015 iMac MK482LL/A, $2,299 USD retail. This is the top standard (not customized) config offered by Apple; with 27" 5K, Skylake i5/3.3-3.9GHz, 8GB RAM, 2TB Fusion, AMD Radeon R9 M395.

I’m trying to open several HEVC (x265) 4K (2160p) sample movie trailers in MP4 format; each about 300-500 MB in size, 1-2 minutes in length. My Windows machine with MPC-HC video player plays these trailers with no problems.

On iMac, Apple QuickTime Player would not open any of these files. Same result with DivX player. VLC opens all of trailers fine, but plays extremely choppy and unwatchable video, at the same time overloading all 4 CPU cores 100%. I’m going through VLC settings, trying to force hardware decoding, however still get the same very choppy video and CPU overload.
So you guys have contradicting results...strange? What could be the reason?
 
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joema2

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So you guys have contradicting results...strange? What could be the reason?
The reason they won't play in Quicktime is expected. HEVC is a brand-new codec. That is a software problem.

I just re-checked the above-linked 4k H265 files from a Samsung NX-1 and upon closer inspection they are somewhat laggy on my 2015 iMac 27. I don't know why it seemed to play OK earlier.

The "Big Buck Bunny" 4k H265 file plays OK, as does the 35 mpbs 4k H265 file from this DropBox folder: https://www.dropbox.com/sh/p2ld7shrvlglyoa/AABprKfXzIyiRgyO9gQqlgsAa?lst

My 2015 iMac plays them a lot better than my 4Ghz Windows PC with a GTX-660.

H265 4k files are so rare it's hard to even find test samples. Most of them are from the Samsung NX-1 which has been cancelled.
 

EnesM

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The reason they won't play in Quicktime is expected. HEVC is a brand-new codec. That is a software problem.

I just re-checked the above-linked 4k H265 files from a Samsung NX-1 and upon closer inspection they are somewhat laggy on my 2015 iMac 27. I don't know why it seemed to play OK earlier.

The "Big Buck Bunny" 4k H265 file plays OK, as does the 35 mpbs 4k H265 file from this DropBox folder: https://www.dropbox.com/sh/p2ld7shrvlglyoa/AABprKfXzIyiRgyO9gQqlgsAa?lst

My 2015 iMac plays them a lot better than my 4Ghz Windows PC with a GTX-660.

H265 4k files are so rare it's hard to even find test samples. Most of them are from the Samsung NX-1 which has been cancelled.
Well, I downloaded X-Men, the full movie (for testing purposes!!!), 26GB, but I don't have the 2015 iMac yet :)

I don't know the source of this file, certainly not 4k Bluray since they don't exist yet, probably ripped from one of the devices that Sony and Samsung offer, but it is definitely H265.


My late 2013 Macbook Pro 13" struggled with it, in fact I need to get home to try it out again, if I remember correctly, I tried hooking it up by HDMI to my 4K TV and it couldn't handle it, too choppy, but I don't remember if it played ok on the Macbook itself.

The funny thing is, the VLC app on my 4K Sony TV (2015 model) had mixed results, it plays it flawlessly every second time or something, and sometimes it refuses to play or becomes choppy.

HEVC definitely needs a bit more polishing and so do the devices and software that play it.

EDIT: Just tried the file on the Macbook, no way VLC could play it...too choppy
 
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mikeboss

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Aug 13, 2009
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just finished downloading "Men in Black" in 4K UHD HEVC H.265 (121.8 GB!!!).
it seems impossible to play this on the iMac Late 2015 4.0 GHz. VLC decodes a few
frames but that's it...
 

EnesM

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just finished downloading "Men in Black" in 4K UHD HEVC H.265 (121.8 GB!!!).
it seems impossible to play this on the iMac Late 2015 4.0 GHz. VLC decodes a few
frames but that's it...
Dang, I want it! I'll try playing with VLC TV app on my Sony. Where did you, um, get it? :D

Edit: I just figured out what you are saying...that's really bad news though, a 2015 max iMac can't handle a format that's going to be standard for the next 5-10 years

How is that even possible? It must be a VLC issue (I sure hope so). But I remember reading somewhere on VLC's site that HEVC system requirements are a quad core i7, and that was last year's info...

Can you post the Media info of the file?
 
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mikeboss

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i got it on the usenet (NNTP).

MEDIA-INFO:
Unique identifier: 211734368342588809948083491648097642352 (0x9F4A8E57A25700BD88FA7B8E4C826770)
Full name: D: \ Downloads \ Videos \ Men.in.Black.1997.2160p.WEB-DL.6xRus.3xEng.TrollUHD-ULTRAHDCLUB.mkv
Format: Matroska
Format version: Version 4 / Version 2
File size: 112 GB
Duration: 1 hr. 37 m.
Bitrate: 152 Mbit / s
Total bit rate mode: Variable
The total flow of 163 Mbit / s
Movie Title: Men in Black (1997) - Release for ULTRAHDCLUB
Date coding: UTC 2015-10-16 17:56:17
Program coding: mkvmerge v8.3.0 ('Over the Horizon') 64bit
Library coding: libebml v1.3.1 + libmatroska v1.4.2
DURATION: 01: 37: 57.860000000
NUMBER_OF_FRAMES: 7053432
NUMBER_OF_BYTES: 1287663958
_STATISTICS_WRITING_APP: Mkvmerge v8.3.0 ('Over the Horizon') 64bit
_STATISTICS_WRITING_DATE_UTC: 2015-10-16 17:56:17
_STATISTICS_TAGS: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
Video
ID: 1
Format: HEVC
Format / Info: High Efficiency Video Coding
Codec ID: V_MPEGH / ISO / HEVC
Duration: 1 hr. 37 m.
Width: 3840 pixels
Height: 2080 pixels
Aspect Ratio: 1.85: 1
Frame rate mode: Constant
Frame rate: 23.976 frames / sec
Title: Men in Black (1997) - Release for ULTRAHDCLUB
Languages: English
Default: Yes
Forced: No
Audio # 1
Identifier: 2
Format: TrueHD
Codec ID: A_TRUEHD
Duration: 1 hr. 37 m.
Type the bit rate: Variable
Maximum bitrate: 3465 kbit / s
Channels: 6 channels
Location of channels: Front: LCR, Side: LR, LFE
Frequency: 48.0 KHz
Compression Method: Lossless
Headline: Dolby TrueHD 5.1 - Blu-ray CEE
Languages: English
Default: Yes
Forced: Yes
 

mikeboss

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Aug 13, 2009
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I also tried it with KODI on OS X (Mac Pro Late 2013, 4 x 3.7 GHz). CPU load 780% and I'm getting maybe 5-10 frames per second :rolleyes:

EDIT:
same result with OpenELEC running on the Mac Pro.
 
Last edited:

florinbss2

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Oct 30, 2015
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First and VLC needs to be updated. So it's a software issue. But the biggest fault gate because AMD did not include a video decoder in the graphics card. Only NVIDIA has hardware video decoding in 960 and 950 video cards.
 

joema2

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First and VLC needs to be updated. So it's a software issue. But the biggest fault gate because AMD did not include a video decoder in the graphics card. Only NVIDIA has hardware video decoding in 960 and 950 video cards.
AMD did not include H265 video decoding on the nMP video cards because that feature did not exist then -- from either AMD or nVidia. It was impossible to include it.

Recent high-end video cards from AMD and nVidia each have their own proprietary video encoding hardware and unique APIs. AMD's is called VCE and nVidia's is called NVENC. This is separate circuitry from the GPU but bundled with it.

For this to work you must (a) have the new card, and (b) the software must support it. As of two days ago Adobe released an updated version of Premiere Pro that apparently supports hardware-assisted H265 encode/decode on certain nVidia cards only.

Since Skylake CPUs have H265 hardware-assisted encode/decode via enhanced Quick Sync, in theory a software update to FCP X or VLC could enable this -- without having to purchase a new video card.

However since Xeon does not have Quick Sync, even an updated Mac Pro with Skylake Xeons would still require an updated GPU to have hardware-assisted H265 support. That GPU could be either AMD or nVidia since they both have H265 encode/decode.
 
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