4K (UHD) QT video on 5K iMac

Discussion in 'iMac' started by mintakax, Nov 2, 2014.

  1. mintakax, Nov 2, 2014
    Last edited: Nov 2, 2014

    mintakax macrumors regular

    Joined:
    Dec 19, 2013
    #1
    When I play a 4K video ( UHD actually) on the new iMac and tell QuickTime to display actual size, it displays a significantly smaller version. To get full res I have to zoom in. This is true when display is set on either of the two higher scaled resolutions.
    Has anyone else run into this ?

    Edit--
    Actually I really don't understand what the scaled resolutions are
    I'm used to seeing actual numbers under resolution settings, not what I see with the 5K iMac
     
  2. Zwhaler macrumors 603

    Zwhaler

    Joined:
    Jun 10, 2006
    #2
    iMac is 5120x2880.
    UHD is 3840x2160. What is the issue?
     
  3. ErikGrim macrumors 68040

    ErikGrim

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    Jun 20, 2003
    Location:
    Brisbane, Australia
    #3
    I’m guessing the issue stems from the confusion of just how much smaller 4K is than 5K. Four to Five doesn’t SOUND a lot, but there is a profound difference of 67% more pixels than 4K:
     

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  4. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #4
    Yep, thats the issue, just a poor perception on my part. I took a screen shot and looked at it in PS and it is the actual size after all. I should have done that before posting :eek:

    Its my wifes iMac and I wanted to see how my 4K videos would look. 5K is a lot of pixels .... made my UHD video look small !
     
  5. ErikGrim macrumors 68040

    ErikGrim

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    Location:
    Brisbane, Australia
    #5
    That’s one of the key reasons Apple went to 5K over “just” 4K: The ability to edit 4K video in full resolution with a full editing UI around it, including timeline and bins.
     
  6. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #6
    I do quite a bit of video editing and after looking at my wife's 5K iMac I think I would prefer a two monitor setup with one monitor being 4K, not 5K. So a 4K (or UHD) video would fill the entire (or almost ) screen at native resolution.
     
  7. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #7
    Also, I wish I understood this scaling on the 5K iMac.

    If I have the scaling set as "best for monitor" and bring up a UHD video at actual size, it is the same size as it is if I have the scaling set at highest resolution ?
    If I have scaling set for a lower than "best for monitor" and bring up a UHD video it is bigger however QT forces it to "fit screen" and "actual size" is greyed out.

    Are there any articles that describe whats going on with scaling ? To me it seems different than just adjusting monitor resolution ?
     
  8. Zwhaler macrumors 603

    Zwhaler

    Joined:
    Jun 10, 2006
    #8
    I'm pretty sure it's scaling just the UI elements to appear smaller or bigger than native res (in which case they would be really really small, take the rMBPs for example).
     
  9. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #9
    Thanks
    I think them sin source of my confusion is that QuickTime does not operate properly on the 5k monitor. When set at "best for display", a UHD video should more than fill the screen when "actual size" is checked. It does not.
    If you set resolution to highest, display the video at actual size, then switch res back to "best", it will show as it should.
     
  10. Frozone9 macrumors member

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    Oct 21, 2014
    Location:
    Zürich, Switzerland
    #10
    No, You still don't get it.

    Everything is in 5K, so a 4K video does not fill the screen.
    But in MacOS everything like menu is bigger so that its usable. Switch the Display to 5K and then You'll see why thats not working.

    So with best for display everything looks like old iMac but much sharper.
     
  11. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #11
    Nope.
    Everything isn't in 5K if the monitor is set to a resolution less than 5K, for instance " best for display" is 2560 x1440. Try it yourself. Take a large jpg and crop it to UHD size of 3840x2860. Set monitor res to best for display, look at cropped JPEG in Preview at actual size. It more than fills the screen as it should.

    Now view a 4K UHD video in QuickTime with res set at "best for monitor" and QT view set at "actual size". It does not display at actual size. Leave it up in QT and switch the monitor to 5K, again change view to actual size, it is not actual size is it ? QuickTime's "actual size " does not work right with this monitor.

    Try the same example with VLC instead of QT and you will see that QT is flawed with this monitor. Exactly what I said in the previous post.
     
  12. paulrbeers macrumors 68040

    Joined:
    Dec 17, 2009
    #12
    While I can't speak to QT because to be honest I don't use it. And while I don't have a 5K iMac, I do have a rMBP. The key is that what OSX is doing is doubling all of the pixels for everything. It's near impossible to explain unless you have a non-retina display sitting next to a retina. So for example, my 15" rMBP set at the default setting (don't have it in front of me, but I think that is "best for Display") only has the same "desktop space" as a 15" non-retina MBP at 1440x900. Why? Because instead of giving you more "desktop space" and making everything god-awful small, instead it uses a 2x2 pixels to represent what was a 1x1 pixels on a non-retina Macbook Pro. The advantage is that that 2x2 can actually have additional definition that wasn't there before.

    With that all said, on my rMBP, I actually prefer the scaling option one up that actually gives me a "usable" desktop size of 1680x1050. It isn't as crisp as the 1440x900, but it isn't too far off.

    Thus yes the riMac would treat it's "default" setting as 2560x1440, but it would add additional detail to text, icons, etc. to give a beautiful image. This is the same process that Apple uses on it's iOS devices as well. You don't get more "space" on a retina iPad (3,4, Air, Air2) compared to a non-retina iPad (original and 2), instead you get a much more crisp image.

    Now again, I can't comment on QT since I do not use it. Why it doesn't show the 4K image full screen when using a scaled size (such as 2560x1440 instead of native 5K)....
     
  13. mintakax thread starter macrumors regular

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    Dec 19, 2013
    #13
    Actually all just probably a moot point .yes the new retina iMac has 5K pickles on it screen all the time, that is true. it's how the display behaves when the resolution is changed with respect to apps like QuickTime that was confusing me
     
  14. AlterZgo macrumors member

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    Mar 17, 2011
    #14
    In both instances, best for monitor or actual size, the 4k video should show at the exact same 3840x2160 pixels and will be identical in size. The scaling best for display Just makes the 27" monitor show text the same size as a non retina 27" monitor but at twice the DPI so the text appears retina smooth. If you display a 3840x2160 video, it will not double the size of that video. If it did, the video would be way to large for the screen. It shows the video in its native 3840x2160 size, but text and all the other elements are rendered at twice the DPI.

    Same happens when you go to a website. If you set it at native resolution, text, pictures, everything will be super tiny in size b/c it will only be about 1/4 as big as a non-retina screen since the retina 5k display has 4x the resolution. Choosing best for display scales everything back up to normal size except that text and native apple icons are now super crisp and have 4x the resolution whereas the images on a webpage are just interpolated or scaled up in size so it appears normal.
     

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