8K video playback/processing question

[arctair]

Just theoretically, should a new 27" 5K Retina iMac with a 3.8GHz 8-core 10th-generation Intel Core i7 processor, 64 GB memory (2 identical Crucial 32 GB cards, one in channel A and one in channel B) and a Radeon Pro 5700 XT with 16GB of GDDR6 memory, connected to the Internet via Ethernet to gigabit Verizon FIOS be able to play this in full 8K resolution (using Chrome):

I mean, even a just a little? Maybe more than three seconds before just going into permanent buffer mode for a full minute before playing another three seconds; repeat? This is just in the standard, small player window that takes up a fifth of my display, I didn't even try full-screen.

Is there something wrong here (it does have Nano Glass lol), or do I have a serious misunderstanding of the video decoding/playback power of this machine?

 

[pldelisle]

Seems like your internet connection is the bottleneck. The machine cannot buffer for seconds, it's likely network related.

The iMac cannot display 8K, so I don't know why you would like to playback an 8K video on a 5K display .....

 

[arctair]

1) When I said "via Ethernet", I thought wired was implied. From 10 GB port to 1 GB switch to FIOS router. The video is loaded and buffered in seconds.

2) It was a test to see what the machine could handle; I'm fully aware it's a 5K and not an 8K screen.

This is my first new machine in ten years. I know exactly what my old Mini can't do; I wanted to see what this one could.

 

[wilberforce]

my experience:

Fan noise on iMac 2020

For me, with an i7 and 5500XT: The link you provided only provides a 4k video on Youtube in Chrome, for me, with no 8k option. The 4k video plays fine, full screen, and fan stays at 1200 rpm. If I download an 8k 24fps video using quicktime such as...

forums.macrumors.com

and

Fan noise on iMac 2020

Its not the network speed. Even if I let it buffer, the CPU cannot decode fast enough. All cores are maxed out on activity monitor, if it is on 8K 60fps: But running the same video in 4k 60fps resolution is fine, fan stays at 1200 rpm. 4k makes more sense than 8k anyway, for a 5k monitor...

forums.macrumors.com

 

[Ynk]

Nothing is wrong, playback of the 4K version in Chrome/Catalina uses up to around 40% of the total CPU capacity of the 2020 iMac if you check. 8K video is 4 times the resolution of 4k and thus is limited by CPU.

Wait until Big Sur is released and hopefully Safari/Chrome will be able to offload the majority of the decoding work to the 5700XT.

 

[wilberforce]

Nothing is wrong, playback of the 4K version in Chrome/Catalina uses up to around 40% of the total CPU capacity of the 2020 iMac if you check. 8K video is 4 times the resolution of 4k and thus is limited by CPU.

Wait until Big Sur is released and hopefully Safari/Chrome will be able to offload the majority of the decoding work to the 5700XT.

I agree, currently 4K/8K videos in Chrome appear to use zero GPU. No wonder it chokes

 

[arctair]

Thanks for the responses y'all. I did download the following: https://images.nasa.gov/details-First-8K-Video-from-Space.html

With the following specs:

And it played smooth as silk w/o a hitch. Also @wilberforce, what are you using to monitor the CPU/GPU code loads?

 

[Nermal]

I tried the untouched Peru video (I have the top-end iMac with i9 and 5700 XT) but I don't have any software that can play AV1 directly. However, I was able to convert it to H.264 and it played fine. I also tried to convert it to HEVC but Compressor wouldn't let me set the res any higher than 4k.

Apparently native AV1 support is coming at some point.

Edit: Just saw your edit. So it seems that 8k HEVC also plays fine... if you have an encoder that works

 

[arctair]

How/where were you able to get the actual video file? Was is a grab from YouTube? Any link to the stand-alone file would be great.

I tried the untouched Peru video (I have the top-end iMac with i9 and 5700 XT) but I don't have any software that can play AV1 directly. However, I was able to convert it to H.264 and it played fine. I also tried to convert it to HEVC but Compressor wouldn't let me set the res any higher than 4k.

Apparently native AV1 support is coming at some point.

 

[Nermal]

I grabbed it from YouTube for testing. I don't have a direct link; I've already deleted it again.

 

[wilberforce]

Also @wilberforce, what are you using to monitor the CPU/GPU code loads?

I just used Activity Monitor
Menu bar: Window
CPU History
GPU History

 

[arctair]

Well, I grabbed a copy of the Peru video (the non-HDR version, despite the video title) as an MP4 file, and both QTP and VLC choked. QT Player said the video "contained some media which wasn't compatible"; VLC played the music but just remained stuck on the first frame. In terms of the same media inspector info from QTP:

It's not HVEC, the resolution and bit rate are actually lower (substantially, in the case of the latter), but FPS is 60. I'll need to try them all again and see what they hit using Activity Monitor (thanks @wilberforce; 20 years on a Mac and I still can't find things in there).