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gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
I got 3 different Macs,
1 pro 5.1 with 6 core 3.06, 40GB ram, 980ti 6gb gpu
1 imac 2011 4 core i5 3.1, 32gb ram and 6970 1gb gpu,

None of those are able to play back 4k files in h264 format without continuous stuttering, showing one frame each second, or iow, impossible to watch, BUT, when i try it on my Macbook pro 12.1 2 core 2.7, 8gb ram and 6100 1,5gb gpu, it plays flawlessly, even straight from a external drive?

Whats the explanation for this?
 

bbrks

macrumors 65816
Dec 17, 2013
1,495
894
Woooowwww, from description of your hardware, you must be a professional in some kind of media science......and you can't answer yourself.....now that's a mystery :)
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
Woooowwww, from description of your hardware, you must be a professional in some kind of media science......and you can't answer yourself.....now that's a mystery :)

Yup, thats correct, and im asking cause it doesnt make any sense to me ;)
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
Tried Preview, QT and VLC, its all the same, or wont make any difference.
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
Its not the software, but the hardware and how it copes with 4k.
 

bbrks

macrumors 65816
Dec 17, 2013
1,495
894
I find it hard to believe, that those two (hardware) can't cope with 4K o_O
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
I find it hard to believe, that those two (hardware) can't cope with 4K o_O
That makes two of us.
I already tried the two top players on that list.
Would be interesting to get to the bottom of this.
 

bbrks

macrumors 65816
Dec 17, 2013
1,495
894
Can't be a hardware problem. My SONY TV has some funny kind of android box inside and plays 4k absolutely beautiful.
Maybe OSX, something inside that could cause poor performance?

Have to apologize for my "stupid" questions, but it's very intriguing :)
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
i think the answer is more complex than just the performance specs, but i was hoping some computer geek could come up with an explanation, or even better, a solution.
 

DeltaMac

macrumors G5
Jul 30, 2003
13,532
4,434
Delaware
Simple answer - Your MBPro is the only one that supports 4K viewing.
The iMac certainly does not.
The MacPro might be good, but your performance sounds like you are limited to single threading from the CPU.
Or, maybe the graphics output is CPU-limited for some reason.

Might be interesting to try viewing 4k video on each Mac, while watching your Activity Monitor/CPU tab. That should quickly tell you how many cores are in use.
 

gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
Simple answer - Your MBPro is the only one that supports 4K viewing.
The iMac certainly does not.
The MacPro might be good, but your performance sounds like you are limited to single threading from the CPU.
Or, maybe the graphics output is CPU-limited for some reason.

Might be interesting to try viewing 4k video on each Mac, while watching your Activity Monitor/CPU tab. That should quickly tell you how many cores are in use.

Not quite correct, it appears to be certain H264 codecs, like from DJI, i have 4k raw files from Sony A7II, with 4 times higher bitrate that plays nice on all units, so its not about 4k.
 

Toutou

macrumors 65816
Jan 6, 2015
1,082
1,575
Prague, Czech Republic
Decoding a heavily compressed 4k video stream takes a LOT of power and is usually done by hardware (i.e. there is dedicated circuitry for decoding video), which is why even powerful older CPUs ( from before-4k-was-a-thing) seem to struggle badly playing a video that a recent netbook wouldn't even worry about.
So that's a thing to consider.
 
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gr8pics

macrumors regular
Original poster
Jan 20, 2008
173
4
Decoding a heavily compressed 4k video stream takes a LOT of power and is usually done by hardware (i.e. there is dedicated circuitry for decoding video), which is why even powerful older CPUs ( from before-4k-was-a-thing) seem to struggle badly playing a video that a recent netbook wouldn't even worry about.
So that's a thing to consider.

How about the gpu, doesnt it matter?
 

orbitalpunk

macrumors 6502a
Aug 14, 2006
564
349
I am running into the same issue with my 2013 Mac Pro trying to play 4k MKV files encoded with h265. Ive tried VLC, MplayerX and IINA with no luck and followed all the VLC tweaks I could find. The best performance I was able to find was to change the container to MP4 and play it in IINA but it eventually stutter later on.
 
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