Amlogic-ng (amcodec): 4k/60hz content corruption

Sample (bikini):

Screen should go fully screwy (try it with a 4k panel that’s capable of 60hz). s905 does not have this problem and the media is decoded correctly while accelerated. The media is displayed correctly if you blacklist 4k and go back down to 1080p.

I noticed other weird issues with 4k content (like the s905x2 is less performant than the s905). The odd effect is also there with 4k/24hz content but it’s less profound.

If you are talking about display corruption when you pull up the OSD during 4K playback, it’s a known problem.
It appears that a true 4K framebuffer is not really supported by Amlogic, basically due to hardware limitations. We were not aware of this when we enabled this during the N2 development, as we have not seen this problem occur on that device. After some thorough testing, I was able to reproduce it on the N2 as well, but it isn’t a prominent issue.
We are still deciding how to handle this problem.

there’s no OSD up - the display is nearly completely corrupt with the sample. 24hz has slight corruption during playback as well (it looks like a fuzz - but it’s super apparent on 60hz).

Does wayland work? I’ve seen binary bins from amlogic but haven’t tested myself.

Try the following command

mount -o remount,rw /flash
fdtput /flash/dtb.img /meson-fb 4k2k_fb 0

And check if it solves the problem with corruption. There could be other layout/gui issues, but I’m interested specifically in 4k playback.
You can then revert back by running

mount -o remount,rw /flash
fdtput /flash/dtb.img /meson-fb 4k2k_fb 1

No change. Corruption is still present as well as lag in 4k/24hz media.

I suspect all 4k display playback has severe problems unfortunately - I’ve tested DCI 4K as well as UHD 4K and they all (30 samples) do not display properly (some even tear! s905 doesn’t have these problems).

CoreELEC:~ # fdtget /flash/dtb.img /meson-fb 4k2k_fb

EDIT: to clarify: the display is not corrupt when amcodec is disabled. However the media playback is thus not accelerated and the lag is horrific so I can’t test for tearing.

@anon88919003 why is this being hidden from the public? @TheCoolest already indicated this is a bug with the stable CoreELEC 9.2.0 release.

Nobody can reproduce your issues and you are reporting issues without so much as providing simple debug or log information.

Posting samples of your porn collection is not really appropriate now either is it.

Btw, maybe it is just bad cable?

Yeah I wish - it’s the latest spec :-(.

The sample was because it blows up entirely and is just that - a sample. I’m unaware of other vendors on the “cutting edge” of media (4k/60fps wasn’t even spec’d until recently) with wacky containers so it was perfect.

Are you guys saying on your 4k setup this is working no problem?

EDIT: and yes - this is confirmed on S905 to playback no problem and is only an issue on S905x2.

Sample doesn’t even start playing here. Make longer one :slight_smile:


HEVC 10-bit 59.940fps (Korean ATSC 3.0 satellite TV capture sample) very clearly shows glitches on S905X2 that are not present on S905 with the exact same cabling and port (sample from ).

OSD like @TheCoolest said is an absolute disaster on S905X2, but even with no OSD up the glitches still happen but less frequently with this media. The glitches do NOT happen with amcodec disabled (but this is super slow as it’s CPU decoded).

Unfortunately I can’t find other media from another vendor that’s cleaner that causes as severe of a problem as this. Here’s another sample from the same sample source as before (splitting is tough when there’s hardly any clean parts). There’s a crude drawing in the first second and the rest is a bum (something you may see at the beach) - LINK REMOVED TO COPYRIGHTED MATERIAL

Source file is: Tiny4K.19.09.12.Allie.Nicole.Bowling.For.Spinners.XXX.2160p.MP4

Disabling amcodec results in no corruption BUT playback can’t be fully tested as the player bails out as it’s missing substantial frames. There’s very clearly severe problems with 4K playback and coreelec-ng/amlogic-ng whereas classic S905 plays this back no problem.

I’m unclear why this is being so significantly censored by @anon88919003 - it’s incredibly misleading to the general public.

Ok I’m done with this thread.