Vero 4K+ lightly stuttering without refresh rate adjustement

I just bought a Vero 4K+ to replace my old raspberry pi 2 and i’m figuring a little issue. First of all i really enjoy OSMC, that’s why i’m getting this new vero for my futur OLED 4K TV.

But i noticed a strange behaviour that i didn’t have with the raspberry. My videos (720p/1080P@23,976 fps) seems to stutter a little on the Vero 4K+. I made some test and trigger the refresh rate adjustement (that was off) on “start/stop” ant it seems to solve the probleme. My tv correctly switch on 1080p/24fps and the video is smoother.

What i don’t understand is that i didn’t have this behviour with the raspberry. I never use the refresh rate adjustement and the videos never seems to stutter with 1080p/60fps refresh rate. It’s not really annoying, i juste have a little black screen delay each time tv is switching to new refresh rate but i’d like to understand :face_with_monocle: :grin:

Should i let the refresh rate adjustement on “start/stop” or is there something i missed ?


It should be set to “On start/stop”, yes.

We recommend people with 4K TV’s set their user interface (UI) to 1080p. Kodi’s UI is not optimized for 4K yet and this can put unnecessary demands on your device and can lead to a suboptimal picture quality, as well as potentially cause other issues.

The settings we recommend are as follows…

Settings>System>Display>Resolution> 1920x1080p
Settings>System>Display>Whitelist> (empty) *
Settings>Player>Videos>Adjust display refresh rate> On start/stop

Some televisions may also need, or benefit from, the following being set…

System>Display>Force 4:2:2 colour subsampling> (enable)

With the above settings your UI will be output in Full HD and your 4K content will be output in 4K. *Information regarding the whitelist can be found here. If you have any doubt, feel free to upload some logs so we can verify that your settings are indeed correct.

Ok thanks for the recommended setting i will stick with display refresh rate on start/stop

And i set the resolution of the user interface to 50hz (instead 60Hz). By doing this, the tv is not switching resolution when i play a 25fps video, so there is no black screen delay. It switch resolution only when i play 23,976 fps video.

Does this setting seem right ?

There is nothing wrong with that. You can also just set the refresh rate switching to “on start” instead so it only switches when you play a video of a different refresh rate from the last video played. The reason for the recommend of “on start/stop” is that it makes for smoother looking (and consistent) transitions in the skin/UI.

I tried the only “on start” option and the transition in the UI was indeed not as smooth. That’s why i prefer this solution :wink:

I’ve got a another question about the “limit GUI updates during playback” option (which doesn’t exist on the VERO 4K+). On the raspberry it is set to 10fps by default. So when i enable the debug logging i can see the fps actually display ant it sticks around 10fps even when i play a movie. Does it means that the movie is actually playing at this frame rate ? It would be weird but i try to understand why the playback of 23,976 fps video seems smooth on my raspberry even with refresh rate disable. Maybe because of this 10fps limit option ??

the fps displayed on the debug overlay is not a correct indicator of the playing video although I forget the details. You can find the framerate that is being output by digging through a debug log as it shows every time it switches or on many displays and AVR’s by bringing up one of their info screens. Limiting the redraw rate of the GUI is a way to reduce CPU load at the expense of smoothness but it has no relation to the screens refresh rate or a video that is playing.

Why you couldn’t see the judder with your old setup is hard to say. I can see it on my RPi’s if I turn off refresh rate switching. The only relevant difference between a RPi and a Vero in this regard is that you can have sync playback to display enabled and passthrough audio at the same time. Without knowing exactly what you settings were on the old unit it is just playing a guessing game though.