[BUG] S905X - BT.2020 video issue

    The bug has been mentioned before but it was lacking an official bug report (and since it seems that the bug not only applys to the alpha version, I decided to make an extra bug report).

    I'm using the latest [WIP] LibreElec alpha version 7.90 (2016-12-04).
    My device is a Sunvell T95X device with a S905X chipset and 1 GB ram
    which is connected to a Samsung 4K HDR capable TV.

    When playing a HDR video, all the black parts of the video turn into grey.

    To reproduce the issue, I just have to play an HDR video file.

    Here is an example video file that creates the issue: uhd-hdr-test-v11.zip
    (There are HDR and SDR video files included for comparison, only the HDR files produce the issue though.)

    I took photos of a HDR and a SDR video playing for comparison (same camera settings):
    HDR:

    SDR:

    (Look at the contrast difference of the writing for example)

    Here's the log: log-2016-12-23-09.31.55.zip

    Here's the mediainfo output of the HDR file: Mediainfo HDR file.txt

    Thanks in advance and merry christmas,
    Hummel95

    Edited once, last by kszaq (December 24, 2016 at 10:51 AM).

    Beside the HDR problem, there is the non-HDR related BT.2020 problem: the chipset doesn't pass regular BT.2020 color to the UHD TV so colors are wrong - desaturated and sickly... Of course, also there is no conversion from bt.2020 to rec. 709 going on inside the box...Don't know what data I should enclose as guideline for BT.2020 implementation... The feature works in android with Deep Color set to "on"

    Sent from my GM 5 Plus d using Tapatalk

    Edited once, last by mytbyte (December 23, 2016 at 12:21 PM).

    It's not a Kodi thing, but in Android system, amlogic library calls probably, it's system-wide, works with any player, and Kodi for Android respects that deep color setting via mediacodec subsystem, as I understand it... Probably could be made as libreelec setting option, not Kodi settings... It's just a HDMI output flag switch/metadata, probably...

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    Edited once, last by mytbyte (December 23, 2016 at 7:23 PM).

    mytbyte There are 2 things that have to be set: "HDR Mode" which is currently an equivalent to "Auto" in my builds and display mode which is handled by Kodi in LE. What needs to be added is Deep Colour mode support detection, Deep Colour switch and proper display mode handling.

    At some point I might look into this, at the moment there are more important bugs that we have to solve.

    Everybody is always welcome to patch Kodi and submit a Pull Request. ;)

    Stige: can you absolutely confirm that you get proper-looking HDR input from the box on your HDR TV and that the TV reports it's receiving HDR signal? That would confirm that the box is not doing HDR-SDR conversion but is configured for native HDR output... That would explain light blacks on SDR TV's, but why then it even attempts to alter the look when all it needs is send picture as is, with added HDR metadata...

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    Edited once, last by mytbyte (February 2, 2017 at 8:19 AM).

    I can at least confirm for my Mini M8S II, that HDR10 is properly output.
    The TV goes into HDR mode and colors + black level appear correct.
    HDR and BT.2020 are shown when checking with TV info button.

    I do however not know, if 10 Bit color depth are output from the box, since the TV does not show that information.

    I hope that helps. :)

    Quote from mytbyte


    Stige: can you absolutely confirm that you get proper-looking HDR input from the box on your HDR TV and that the TV reports it's receiving HDR signal? That would confirm that the box is not doing HDR-SDR conversion but is configured for native HDR output... That would explain light blacks on SDR TV's, but why then it even attempts to alter the look when all it needs is send picture as is, with added HDR metadata...

    Sent from my GM 5 Plus d using Tapatalk

    Yes it's 100% correct HDR. TV recognizes it the moment the movie starts and shows the "HDR video playing" popup in top left corner as usual.
    And black are as good as they are when I play the same file directly on the TV.

    Cool. Thanks to all three...On SDR TVs it looks wrong, washed-out black and compressed gamma...I'd hoped the s905x boxes would do HDR->SDR and BT2020->BT709 conversion but they don't, they just pass them out to HDMI with descriptors for the TV to take care of it...so, if you happen to aquire or start accumulating some HDR and UHD material for, say, future switch to UHD HDR display, there is no way to watch them on legacy displays now...

    Edited once, last by mytbyte (February 2, 2017 at 10:52 PM).

    Quote from Stige


    Here is a quick photo I took:


    Are you playing from USB hard disk or streaming from addons ? I can't get HDR to work on either options.
    Please share the video setting information.

    Using LE 5b on s905x, 2gb ram
    Samsung 60" 4K tv


    Sent from my iPhone using Tapatalk

    Quote from ssarava9

    Are you playing from USB hard disk or streaming from addons ? I can't get HDR to work on either options.
    Please share the video setting information.

    Using LE 5b on s905x, 2gb ram
    Samsung 60" 4K tv


    Sent from my iPhone using Tapatalk

    I was playing the file from my PC over DLNA (Universal Media Server), works fine. Your TV needs to be in Movie mode I think to automatically recognize HDR.
    Havent tested anything on USB yet.

    Edited once, last by Stige (February 7, 2017 at 8:25 PM).