4k upscaled judder on 25FPS movies

Hi all
I have an TX8 S912 AMLogic device with last CoreELEC build and new Sony X800H TV.
This TV give a good upscaling to 4K but I would like to use my box instead to discharge the Sony’s X1 processor.
So I use my box to upscale to 4K I get very good display with 24FPS movies but with issues on 25FPS movies. I use the default coreELEC settings… I can say this do not happens with 1080p I get very good display with 1080p out but when I switch to 4k I get some judder on 1080p 25FPS movie’s. No white list, only default settings
When I set the box to 1080p I get “perfect” 50Hz for the 25FPS 1080p movies upscaled by the TV to 4k but with judder if I set the box to diplay 4k.
I saw somewhere Sholander said about the S912 SoC which is not powerfull enought to upscale 25FPS Netflix movies to 4k and something else but I’m looking to know if there is some settings to tweak to fix my issues… ?

Not sure but this may help ? I think you have to set your box to 1080p but I’m not sure … I have same issue but with x950h Sony UHD here

The Netflix issue is usually to do with software decoding, not upscaling, because the way Netflix is decoded means you can’t use hardware acceleration, and some CPUs can only decode 720p not 1080p streams.

If you haven’t whitelisted modes - have you enabled Refresh Rate Switching in Player settings? (eIther on Start/Stop or on Start)

I haven’t used an S912 for a while (I’m S905X3 and S922X based now) but have had no issues with Sony UHD TVs and 2160p50 output (I don’t use 2160p25 output). However I usually use my Sony TV’s built-in upscaling as it’s higher quality than the relatively basic AMLogic upscaling.

Hi thanks for this infos
My box / CoreELEC give a very good upscaling same or better then my UHD Sony tv … The refresh setting is enabled at on start/stop and I don’t have any whitelist selected but you mean I can select some to have a good stream in 4k ? Sorry I’m little confused… I have same issue as linuxo…

Whitelisting is more to do the opposite of what you want. Most of us want 720p and 1080p content output at native resolution, as our TVs do better quality upscales than most of our CoreElec boxes. By enabling whitelisted resolutions and frame rates you can avoid the poorer quality AMLogic scaling.

Do you have MotionFlow enabled on your TV - so that 24 and 25fps stuff is artificially smoothed out to 100/120Hz (or 50/60fps)? I wonder if your 1080p25 files are output at 2160p50 when CoreElec upscales and your TV doesn’t apply motion flow to this format - so you see things at their native frame rate, rather than heavily motion processed?

If you disable Motion Flow is the 2160p output still more juddery than the 1080p output?

Hi thanks for this infos
Motion flow enabled or not give the same judder on 25fps movies streamed at 4k/24Hz from my box (I do not have Netflix) i don’t have choice my box upscale to 4k/24Hz all 25fps movies but at 50hz if upscaled to 1080p this is odd
In white list I can not change this
If I do not upscale with the box I stream to 1080p at 50Hz with no judder

When the box upscale to 4k it stream at 24Hz all 25fps movies this is odd and this is where I get judder. Same box upscale to 4k / 24 or 60 Hz all other movies without issue

I don’t have any judder too when the box upscale to 1080p any movies 25fps or not and then my tv upscale to 4k but …like linuxo I would like to discharge the X1 Sony’s processor this is why I want to use my box to upscale to 4k instead the tv and this work but this not work for 25fps movies only…

Yes thanks to you noggin and Atlas. its exactly the same issue as Atlas describe I get judder on 1080p/ 25fps movies streamed at 4k from the box motion flow enabled or not

Ah - this is new information. I missed the point where you said 1080p25 content was being output at 2160p24. That’s going to judder badly…

So the question is why 25Hz content is being output at 24Hz.

Which HDMI input are you using on your Sony UHD TV, and have you enabled Enhanced HDMI input in the TV Set-up menus? My Sony UHD TVs (XE9005 and now XF9005) will only accept Enhanced HDMI on inputs HDMI 2 and HDMI 3 (HDMI 1 and HDMI 4 are 4:2:0 only for 2160p50/60). If you are routing through an AVR - has Enhanced HDMI been enabled on that too?

I suspect there MAY be an issue related to >30fps 2160p support going on here.

It may be that for 1080p25 to be output cleanly the display path needs to support 2160p50 (to allow for 2:2 output of 25p). Not all combinations of devices support 2160p25 (just 2160p24, 2160p50 and 2160p60, and some combos of devices need Enhanced HDMI support enabled for 2160p50 and 2160p60 support)

Others here may be able to tell you how to SSH in to your CoreElec box and find out what resolutions and frame rates your TV (and AVR if in circuit) support with your CoreElec box via EDID.

Thanks for your time
It’s new UHD Sony’s models so it’s enhanced out for the 4 HDMI plugs and I use the first one for the box with enhanced selected (selected or not give same display)

Woooooo noggin you spoke about 2160p and you flash the light … I checked my CoreELEC output and I saw that I selected bad output 4096x2160p so I switch it to 3840x2160p and that’s work now I get no judder on all movies and 50Hz on 25fps !!!
Thanks for your help
PS linuxo I think you have same issue as me try this fix it’s glitch from CoreELEC ? 4096 has nothing to do here in settings ?


Fixed !
Thank you Atlas and noggin !
Sony UHD TV X800H have 4 enhanced hdmi too and true motion do not work for fixing judder … it was the setting output 4096 my problem like Atlas…


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