Nightly builds (NEW)

Maybe, maybe not. Better start with a fresh flashed spare boot media.

No idea, you will ask in Kodi forum what this can cause and if it works still like this!?
And to be honest: you add such “undocumented” modifications and want us to support it when something is (maybe) wrong?

Well unfortunately, a new clean install of CE from Oowow gives me exactly the same results. I remind you that some of these bugs appeared following an CE update which took place around November.

Reminder of all bugs to date :

  • Player OSD pop-up artifacts during playback of some 1080p @30hz movies (When GUI Scaling is disabled)

  • Crash when advancing to the first chapter, on some isolated films

  • Loss of network when exiting standby

  • Display settings 1080@120hz → black screen / crash

@Portisch
I may have an idea why you couldn’t reproduce the artifact problem. I just noticed that this bug appears only when disabling “scaling” in the display settings. (the scaling of the interface generates so much aliasing on the covers that I always had the reflex to deactivate it)

Sorry, we are not working exclusively for you. We are very busy at the moment…

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I never doubted it. I will wait for you to come back to me. Good luck with all your hard work.

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So maybe a big issue with dmabuf & ion_buffer handling is solved in next NE nightly. At least it’s now possible again to restart Kodi more than 1 time :grin:

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Luckylukz confirmed to me in PM that the artifact bug was reproducible by disabling the interface scaler.

You need to be a bit more in detail! Disable GUI scaling enabled or disabled?

If the option is enabled it limit fb to 1080p, if disabled it uses Kodi 4k inbuilt scaling.

Disable GUI scaling = “check” the “Disable GUI scaling” option. When this is the case, artifacts appear, but particularly when the OSD appears when playing 1080p@30hz videos.

Unrelated question : Did the CE devs create this scaling ?

It’s history and was since day one there. It’s somehow the 4k Kodi GUI have issues and with this option enabled the GUI is 1080p and scaled by kernel to 4k.
Maybe @Ray or @TheCoolest knows more about it.

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Thank you for this info. The problem with this scaling method is that it generates a lot of aliasing on some covers. On 65" and larger TVs, it’s very visible. The rendering is much better without it. Finally, that’s not counting the artifacts. The ideal would be to review the scaling method, perhaps drawing inspiration -be newer methods employed (DLSS2). Or just debug mode without Scaling. I did not have these artifacts on my previous boxes. Quite frankly, without this problem, for me this VIM 4 would be the current best box for CE From afar! The other “small” bugs I’ve reported are much more occasional. We can live with them. It’s the best, for its ergonomics (Oowow), for its performance (flop)/consumption/size ratio. You can create high definition environments without affecting the fluidity of the interface. This is unprecedented for a low-power box. Good if anyway. This story of HD sound is still surprising. Surprised it took so long.

I’m putting a video sample that favors the presence of these artifacts and an extract of what it looks like : 652.33 MB folder on MEGA

Last time on NG the audio part took 1-2 years.
And for your scaling issue solve is may best you join Amlogic and help them about how to adjust the hardware registers. We have no such special developer for this and even no complete register description.

So I would see to talk about a scaling that would make the best use of the chipset with Amlogic.

But in the meantime, isn’t it possible to debug the display without scaling ? This problem does not appear on other OS (Linux, Android). So I guess it comes exclusively from CE. I think it’s an image sync issue.

By the way, a remark :
This is uniquely noticeable on the OSD when playing 1080@30hz and 4k@60 and 4k@59.940 video. But it is also present outside reading when the interface is set to 60hz, 30hz and 59.940hz. (present when entering a file and coming out of it, for example). On the other hand, if the interface is at 50hz, or at 24hz, there is no artifact. Ditto in 4k@24, or 4k@50 video playback, no artifacts. So, i assume that the problem is related to the refresh (30hz, 59hz and 60hz).

The question is who will invest hours/days for debugging, research and trial and error for Hobby?

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I think that the last time we looked into this was like 2 or 3 years ago.
Eventually, I think that we reached the conclusion that this was a hardware limitation. Possibly memory bandwidth limit, or something like that.
Normally, at 4K resolution, the GUI is downscaled to 1080P. With the scaling disabled, the GUI is rendered at 4K, which doesn’t work well on some devices. On some it’s “usable”, where the artifacts are rare. On others it’s unusable at all because it messes up everything on screen.

Edit :

Thank you for these clarifications TheCoolest.

A hardware limit ? But then why do we not encounter these artifacts on other OSes in 4k@60hz ? Even Kodi on Android does not have this problem. And I don’t believe in a memory limit, because these artifacts are not present in 4k@50hz, 30hz, 24hz (Artifacts disappear with a frequency other than 60hz.).

I don’t have a technical explanation. It’s what I remember we were able figure out when we spent time on looking into it. It’s also possible that the techniques used by the different OSes to render the GUI are different, which may result in the difference in behavior you see.

EDIT :

But Kodi on Android doesn’t have this problem either. For me the problem comes from CE. But it is indeed complicated to flush out.

The fact that the bug is absent on all frequencies between 24hz and 50hz is perhaps a clue. This bug only occurs on the 59 and 60 Hz frequencies. In video playback, the bug appears on 4k@60 and 1080p@30hz sources, but the interface switch back to 4k@60hz on that source 1080p@30hz. Which would confirm that the problem is only related to the frequency close to 60hz.

What about 100hz or 120hz ?
I don’t really believe it, but may be the bug wouldn’t occur with a 100hz or 120hz refresh. Is it possible to integrate a 4k@100hz ans 4k@120hz options ? Even if it doesn’t solve the problem, it won’t be a wasted effort. @120hz GUIs are becoming quite common.