EDIT1: I've narrowed down the problem somewhat but still not sure why the problem is occurring. The video in question is 29.97Hz, and my display is set to 59.94Hz. Simple playback outcome, right? Refresh is an even multiple of framerate so the shield just needs just show every frame twice and there's no need to timestretch/resample audio to match. For some reason, that's not what's happening; it's as if it is sometimes showing frames 3 times and sometimes 1 time, like a weird unnecessary judder. If I force the ShieldTV to output 29.97Hz, the problem goes away. But I shouldn't need to for the reasons I just pointed out. It's also worth noting that 60fps 4K videos on YouTube don't have the issue, only 30fps when output at 60Hz.

EDIT2: It appears that the issue is connected to, or caused by, the YouTube v2.01.04 update. Reverting the the stock v1.x version causes the stuttering issue to go away.

ORIGINAL POST

I'm in the early stages of setting up an nVidia Shield TV 2017 with a 55" LG OLED (OLED55B7P) and my initial results are not great.

After the first setup, the system updated itself to 6.1 firmware and updated the firmware for the remote and controller. Wanting to start off with a system as "fresh" as possible, I opted to do a factory reset after all firmware upgrades.

After the factory reset, I rebooted the unit, added my Google account and did the other initial setup stuff. First thing I noticed was that I couldn't get the voice search to work with the remote or the controller, I just kept getting an error that it "couldn't connect.. try again later". The internet connection seemed fine, I was able to browse videos in YouTube, and they played. Reboots didn't fix the problem, so I decided to do another factory reset since I wasn't too far along anyway. After the factory reset, the voice search was working again. No idea why it didn't work the first time around.

Ready to finally do some testing, I checked the display settings on the Shield and confirmed it was running at 3840x2160 @ 59.94 - YUV 4:2:0 10-bit Rec. 2020.

For the first test, I first wanted to compare YouTube playback - The LG TV's native WebOS app vs the nVidia Shield TV.
Video tested: "SONY 4K hdr demo video for 4k tv-2160p" - https://www.youtube.com/watch?v=Bey4XXJAqS8be
(I don't think the video is HDR despite the title, but is 4K. Youtube-dl reports the video is 30fps, and the downloaded version shows 29.97)

Here's my results:

(1) Using WebOS YouTube app, TruMotion off.
Video appears to play at a consistent 30fps. Less fluid than 60fps material, but no pausing or stutters noticed.

(2) Using WebOS YouTube app, TruMotion set to 'Clear'.
As expected, video plays fluidly and looks like 60fps+. Some Motion Estimation artefacts but plays well overall.

(3) Using YouTube for Android TV app on nVidia Shield TV 2017, TruMotion off.
Video is much choppier compared to the native YouTube app on the TV. Noticeable stuttering and pauses.

(4) Using YouTube for Android TV app on nVidia Shield TV 2017, TruMotion set to 'Clear'.
Smoother than with TruMotion off, but still very noticeable pauses and stutters.

Are these results typical? Unless I'm doing something wrong, it appears that YouTube videos are much choppier on the nVidia Shield compared to the "native" WebOS YouTube app on the TV. I bought the Shield to get away from essentially the same playback issues on the Xiaomi Mi Box, but it's just as bad.

I'm just beginning to scratch the surface and already finding problems significant enough for me to ditch the Shield and stick with the native WebOS apps. I really wanted to do as much as possible through a single interface (and have KODI), but if I lose playback quality to get that then it isn't worth it to me.

I'm open to all suggestions and ideas. I'm new to the ShieldTV, so if there's a better place to get support please let me know.