[TESTING][S905(X)] 10bit/HDR/Dithering Test Builds & Discussion

Quote from wrxtasy

I've been running a AML S912 / Kodi v18 Leia Alpha experimental - johngalt Kernel build over the weekend and getting nice results from a MINIX U9.

I have not noticed any video banding, and watched 2 movies over the weekend and did not detect any frame skips at all, I can normally spot frame skips easily.

I will have to do more testing with HDR10 output to my 10bit (non HDR) 4K TV before commenting further.

Thank you. I just watched a full (high bitrate) h264 movie and checked the overlay toward the end and saw no skips . At this point, I think I can safely recommend the "nougat-exp" kernel branch for improved HDR -> SDR conversion. On S912, it should also now have full dolby vision decoding support (need to enable new config option). Can't recommend the branches due to playback issues on h264.

You can also try setting /sys/module/am_vecm/parameters/panel_max_lumin to your display's luminescence in nits (e.g. echo 400 > /sys/module/am_vecm/parameters/panel_max_lumin). Just because you're watching HDR material in SDR, doesn't mean it should be graded for 100 nits on a 300 or 400 nit display. I think the only issue with this is that most have the brightness set lower to accomodate 100 nit graded sources, so without a "HDR mode", you'd be modifying brightness on the fly to accomodate both. But it's something to play with if you're feeling like it

Quote

Unfortunately the "testing1" build still has some lower grayscale flicker.

I've yet to test, but native (4:2:2) or 4:2:0 output might be better. I need to test and fix setting 4:2:0 completely.

Quote from 2re

So far, So good! Only problem is major frame skips on some media. Can't pinpoint the exact type but it looks like it's only on some 720p types. I'll do some more testing and see if i can isolate the specific type.

ps. If I disable "Adjust display refresh rate" and playback at 60hz, then the problem is gone.

On which build? "experimental," "testing," or both? Could you provide a test file? Perfect timing, just saw you uploaded a test file

Quote from Jaaxx

Any chance Kszaq's OpenSSL will port over to these builds?

It definitely will, but I haven't debugged why I can't build with those changes (even clean). I'm sure I'll be able to figure it out without a chroot since I can build master without issues. However, these changes shouldn't stay in their own builds very long.

Update: I just deleted the "exp2" build from the release page. At this point, it seems the only issue with it are very bad frame skips on some h264 files.

I'm now starting the work to merge the stable changes into upstream ( kszaq repos) and hopefully get more testing from users who had nougat output issues. The "exp" work can continue in parallel until ready for merge.

Quote from 2re

Anyone else get Major frame skips playing this file with the latest build(exp2):

open?id=0B3aL3ABBc7dMNWVxSVFHTUd5VjA

I can confirm these frame skips and am working on it. They're also gone in "testing1" due to the amports reverts.

Quote from jd17

johngalt you said that exp builds would not have the "vertical lines" artifacts?
Unfortunately I missed downloading the build while it was still up...
Is this version on the server right for testing?:
8.0.2-exp2.tar.gz

That was a mistake re: exp1. In that build I messed up 8bit output + dithering. There will be no change between exp2 and testing1 in terms of 10bit output quality. I don't recommend the "exp" builds until the h264 issues are fixed.

The "testing1" build is in the same state as the PRs I just submitted to kszaq for merging . To clarify, the main real world impact of the "exp" branches right now (aside from h264 bugs) are either HDR->SDR related or S912 specific.

Quote from jd17

OK.

Just a quick update:
Cables are here - critical files play perfectly.
No signal losses anymore.

I can still retest the old cable if you wish, probably tomorrow.

BTW, would "echo '420,10bit' > /sys/class/amhdmitx/amhdmitx0/attr" or "echo '420,8bit' > /sys/class/amhdmitx/amhdmitx0/attr" work on the testing1 build?
I want to see if I can fool my AVR and passthrough at least a 2160p / 8bit / BT.709 / 23.976fps file...

I know "420,10bit" won't work, but I'm not sure about "420,8bit". I think manually setting 4:2:0 at any depth will fail. However, you can run 422 instead of 444 if you wish. I think the artifacts I got from it on initial testing may have been from when dithering was globally enabled.