Forum Discussion

garthcas's avatar
garthcas
Binge Watcher
3 years ago
Solved

Why no 4k with Roku Ultra?

I recently purchased:   - a LG Class C2 AUA series OLED evo 4K UHD TV, with HDMI at @ 120 Hz, HDCP 2.2, and HDR (Dolby Vision, HDR10, HLG);   - a Roku Ultra 4802R with HD/4K/HDR;   - a Pion...
TV & Player Setup
  • atc98092's avatar
    atc98092
    3 years ago

    Well, I'm crossing my fingers for you that the Pioneer experts can tell you a setting to change to make it work correctly. I had a hunch it was the AVR, but troubelshooting from a distance is not an easy task. Glad you've confirmed the Roku is working as expected. 🙂

garthcas's avatar
garthcas
Binge Watcher
3 years ago

Thanks for the suggestions!  I confirmed that the LG TV is set Deep Color / 4K.  I can find nothing in the Pioneer AVR setup or in the on-screen or written documentation about any kind of "passthrough" setting.  I just submitted a technical support request form to Pioneer asking about that and about how to enable 60 fps.  We'll see what happens!

atc98092's avatar
atc98092
Community Streaming Expert
3 years ago

I looked up the specs for your Pioneer. As you probably know, it's at the low end of their model series, and this might be the issue here. This is what they list for the HDMI ports:

Color space (Color Depth):
720×480i 60 Hz,
720×576i 50 Hz,
720×480p 60 Hz,
720×576p 50 Hz,
1920×1080i 50/60 Hz,
1280×720p 24/25/30/50/60 Hz,
1680×720p 24/25/30/50/60 Hz,
1920×1080p 24/25/30/50/60 Hz,
2560×1080p 24/25/30/50/60 Hz,
4K (3840×2160p) 24/25/30 Hz,
4K SMPTE (4096×2160p) 24/25/30 Hz : RGB/YCbCr4:4:4 (8/10/12 bit), YCbCr4:2:2 (12 bit)
–4K (3840×2160p) 50/60 Hz,
4K SMPTE (4096×2160p) 50/60 Hz :
RGB/YCbCr4:4:4 (8 bit), YCbCr4:2:2 (12 bit), YCbCr4:2:0 (8/10/12 bit)
 
This isn't the clearest information, but notice the line I highlighted. Under some signal configurations, your AVR will only passthrough 4K at 30Hz. I can't say if that's the exact situation the Roku is putting out, but it does seem suspicious. They do list 60Hz available with some other 4K resolutions, so perhaps this isn't the issue.  Hopefully your contact at Pioneer will have a better answer. 
  • garthcas's avatar
    garthcas
    Binge Watcher
    3 years ago

    Thanks atc98092.  If that's the case, I guess it's ultimately my fault for not understanding the implications of that limitation in the fine print.  But this is all very confusing to a layperson like me.  I'm not an expert in these matters, but I found this in a product sheet for this AVR, which misled me:

    Ultra HD pass-through with HDcp 2.2 (4K/60p/4:4:4/24-bit, 4K/24p/4:4:4/36-bit, 4K/60p/4:2:0/36-bit)

    It seems like Pioneer and Roku could have made it clearer that these products are incompatible for achieving 4K.

    Can you explain, is 60 fps (which Roku refers to) the same as 60 Hz (which Pioneer refers to in their specs) the same as 60 p (which Pioneer refers to in the product sheet)?

     

    • atc98092's avatar
      atc98092
      Community Streaming Expert
      3 years ago

      Yes, 60fps and 60Hz is basically the same thing. 60p also refers to the refresh rate, but the p identifies the image as progressive scanning, while an i (such as 1080i) refers to interlaced scanning. Both harken back to the old cathode ray display days where an electron gun was "painting" the screen. Progressive scans an image one line at a time, while interlaced would scan every other line, then go back and fill in the missing lines. With digital displays it's really no longer necessary to label them like that, but old habits die hard. 

      You can't really fault Roku in this instance. There's no way they could identify every possible equipment combination that might be encountered in the real world. 4K Roku players can output 4K/60 at 4:2:2 and 4:2:0. There's a setting under System/Advanced Display Settings to switch between the two. You might try changing that and see if your TV will accept the Roku at 4K/60.

      • garthcas's avatar
        garthcas
        Binge Watcher
        3 years ago

        OK, fair point, I can't really fault Roku.  But perhaps I can fault Pioneer for only recognizing one 4K protocol when a major manufacturer like Roku adheres to a different one.  Seems like Pioneer cheaped out on this.  How hard/expensive would have been to handle both?

  • Anonymous's avatar
    Anonymous
    3 years ago

    This does NOT indicate the AVR won't pass 4k/60. It only indicates that the colorspace for it will not be RGB or YCbCr 4:4:4.

     

    Color space (Color Depth):

    "4K SMPTE (4096×2160p) 24/25/30 Hz : RGB/YCbCr4:4:4 (8/10/12 bit), YCbCr4:2:2 (12 bit)"

    That, and all the resolution/refresh combinations above it, will allow a colorspace of RGB or a 4:4:4 subsampling, whether at a 24, 30, or 36 bit depth, or 4:2:2 at 36 bits.

    "4K (3840×2160p) 50/60 Hz,
    4K SMPTE (4096×2160p) 50/60 Hz :
    RGB/YCbCr4:4:4 (8 bit), YCbCr4:2:2 (12 bit), YCbCr4:2:0 (8/10/12 bit)"
     
    Those two 4K/60 resolutions will allow a colorspace of RGB or 4:4:4 at 24 bits, 4:2:2 at 36 bits, or 4:2:0 at any bit depth.
     
    Just enable "auto-adjust display refresh rate" and most likely any HDR content will be 24p anyway, and it'll pass 4K/24p at 4:4:4.
     
    If the content is actually 4K/60 the color subsampling can be RGB or 4:4:4 only if HDR is off. You can choose between 4:2:2 and 4:2:0 in the Roku setting for HDR subsampling, and the AVR will pass it through. 
     
    That's the way I read it. In my case, with a low-end Samsung (HDR 10, 10+) and Ultra 4670x (HDR10) I get 4:4:4 on 4K/24p HDR content, and 4:2:0 on any 4K60p content. 
     
    (8 bits per channel=24, 10=30, 12=36 bit depth)
    • garthcas's avatar
      garthcas
      Binge Watcher
      3 years ago

      Thanks for joining in 011.  I must admit I'm not an expert on this and much of it goes over my head.  I do have Auto-Adjust Display Refresh Rate set to ON, and HDR Always On set to OFF.  But I'm still confused why the Display Type still defaults to Automatic (1080p Dolby Vision), and discourages me from manually setting it to either 4K Dolby Vision HDR TV or to 4K HDR TV (saying it's not recommended).  It seems to be okay with manually setting it to 4K TV, however.  Should I ignore the "not recommended" warnings and select one of the 4K settings, or just leave it on Automatic (1080p Dolby Vision)?  Also, with HDR set to Off, I won't be able to get any benefit from this?  My rudimentary knowledge held that HDR was a good thing to have.  Ditto for Dolby Vision.

      • Anonymous's avatar
        Anonymous
        3 years ago

        As far as selecting a resolution manually, definitely try each one. My 4670 Ultra displays a picture and asks if it looks ok; if you don't respond after a few seconds timeout, it will revert to the resolution you started with (so don't touch the remote if you don't see what I described).

        Mine also has an option right below the auto-adjust refresh option, for HDR sub-sampling; try 4:2:0 and 4:2:2 to see if it has any effect on your results. EDIT: This won't appear when the display output is 1080p, at least on my model of Ultra.

        First troubleshooting I'd do is connect Roku direct to TV, try both cables and all HDMI inputs. Try swapping roku to AVR and AVR to TV cables.

        There's nothing in the specs on that AVR to indicate that it wouldn't work. See if you can isolate it to the AVR. And there's an option 1080p -> 4K Upscaling, default Auto, on that AVR. Turn it off. It's unnecessary, the Roku should output everything at 4K anyway, and if some other source is 1080p, the TV probably has a better scaler. Let us know if you have any luck.