Can someone explain why i cant play back 4k files?

Discussion in 'Mac Basics and Help' started by gr8pics, Feb 18, 2017.

  1. gr8pics macrumors regular

    gr8pics

    Joined:
    Jan 20, 2008
    #1
    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?
     
  2. bbrks macrumors 65816

    bbrks

    Joined:
    Dec 17, 2013
    #2
    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 :)
     
  3. gr8pics thread starter macrumors regular

    gr8pics

    Joined:
    Jan 20, 2008
    #3
    Yup, thats correct, and im asking cause it doesnt make any sense to me ;)
     
  4. robotica macrumors 6502a

    robotica

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    Location:
    Edinburgh
    #4
    What program you using to watch these 4K files?
     
  5. gr8pics thread starter macrumors regular

    gr8pics

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    Jan 20, 2008
    #5
    Tried Preview, QT and VLC, its all the same, or wont make any difference.
     
  6. bbrks macrumors 65816

    bbrks

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    Dec 17, 2013
    #6
  7. gr8pics thread starter macrumors regular

    gr8pics

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    #7
    Its not the software, but the hardware and how it copes with 4k.
     
  8. bbrks macrumors 65816

    bbrks

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    #8
    I find it hard to believe, that those two (hardware) can't cope with 4K o_O
     
  9. gr8pics thread starter macrumors regular

    gr8pics

    Joined:
    Jan 20, 2008
    #9
    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.
     
  10. bbrks macrumors 65816

    bbrks

    Joined:
    Dec 17, 2013
    #10
    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 :)
     
  11. gr8pics thread starter macrumors regular

    gr8pics

    Joined:
    Jan 20, 2008
    #11
    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.
     
  12. satcomer macrumors 603

    satcomer

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    Feb 19, 2008
    Location:
    The Finger Lakes Region
    #12
    Read AppLe Support document Using 4K displays, 5K displays, and Ultra HD TVs with your Mac and it will answer your question.
     
  13. gr8pics thread starter macrumors regular

    gr8pics

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    Jan 20, 2008
    #13
  14. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #14
    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.
     
  15. gr8pics thread starter macrumors regular

    gr8pics

    Joined:
    Jan 20, 2008
    #15
    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.
     
  16. Toutou macrumors 6502a

    Toutou

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    Location:
    Prague, Czech Republic
    #16
    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.
     
  17. gr8pics thread starter macrumors regular

    gr8pics

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    Jan 20, 2008
    #17
    How about the gpu, doesnt it matter?
     
  18. Toutou macrumors 6502a

    Toutou

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    #18
    Yeah, the GPU does matter, that's why it doesn't make sense to me. The GPUs in both your iMac and the Pro should offer 4k H264 acceleration.
     
  19. DeltaMac macrumors 604

    DeltaMac

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    Location:
    Delaware
    #19
    There would also be some difference between the files that play, and those that struggle.
     
  20. gr8pics thread starter macrumors regular

    gr8pics

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    Jan 20, 2008
    #20
    Thanks, so im not way off then...
     
  21. orbitalpunk macrumors 6502

    orbitalpunk

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    Aug 14, 2006
    #21
    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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