RPi4 testbuild with HDR support

  • Hi there,

    just tested it. All set back to 'auto' ...... BT.2020 colorspace switching is now working, even when I jump directly into the movie.

    Great Job ...... only bug was ..... while testing I had no coffee ....

    Have a nice weekend ......

    If it's idiot-proof, someone will build a better idiot.

  • Hi,

    Thank you for the release,

    It doesn't seems to work for me, I still see RGB 24 bits on my AV.

    I have the following message :

  • Just tested - 2160p25 10-bit HEVC Rec 2020 HLG content is output 2160p25 RGB 8-bit Rec2020 flagged and with an HLG ARIB B67 EOTF. Progress!

    Not sure I get the 'whitepoint' stuff - the whitepoint metadata (which is I think the CIE x and y co-ordinates of the mastering whitepoint used in the grading process) carried in HDMI InfoFrames (and in the HEVC video) is separate to the RGB<->YCbCr matrix stuff ? (This is the HDMI Infoframe stuff that is carried along with stuff like MaxCLL and MaxFALL mastering data in HDR10/PQ stuff)

    However in the Rec 2020 YCbCr<->RGB matrix there is more Red and less Green and less Blue contribution to the Y signal - so if you use a Rec 709 matrix instead I think you'll get a picture skewed less red and more green/blue than it should be?

  • As HiassofT said - the output is still 8-bit (so will be RGB 24 bit if your AVR reports that) not 10- or 12-bit.

    However it is now correctly flagged with Rec 2020 colour gamut, rather than Rec 709 :

    "DEBUG <general>: CVideoLayerBridgeDRMPRIME::Configure - setting connector colorspace to BT2020_RGB"

    So the colour primaries flagged to your display are now correct, as well as an HDR EOTF also being flagged (so the for HDR10 content the connected display will now go into Rec 2020 AND HDR mode, using a PQ/ST.2084 EOTF - i.e. the right wide colour gamut and the right dynamic range)

    What isn't yet happening is 10-bit or 12-bit output (so the 10-bit HDR HEVC video is truncated to 8-bits, losing the two least-significant bits - potentially causing banding) and also the RGB<->YCbCr matrix being used is likely to be that for Rec 709 rather than Rec 2020 (the two standards use different matrixes to convert between the RGB that Kodi uses - and currently outputs - and the YCbCr video carried in the HEVC codec)

  • The build also contains current WIP HEVC optimizations and latest kodi Matrix changes. High-bitrate and 50/60fps HEVC videos should perform better now but beware, there might still be bugs :)


    Is 2160p50/59.94/60 output now supported in these builds? Or is this note about high bitrate & 50/60fps content just for output at 1080p50/59.94/60 and below?

    Edited once, last by noggin ().

  • Not sure I get the 'whitepoint' stuff

    Sorry, I should have better avoided the term "whitepoint" in this context. What I meant was what you mentioned later, due to the wrong matrix the RGB values won't be quite correct, colors skewed, and white won't be white.

    4kp50/60 output isn't implemented in this build, this is still in the queue (we tested an early patch a few weeks ago but it's not 100% there yet).

    4kp50/60 HEVC decoding is more performant now, so 1080p50/60 output of such files will be a lot better (previously the decoder couldn't keep up resulting in a/v sync drifting away). These optimizations are still WIP but testing showed it's already mostly working fine.

    so long,


  • Haven't tested 2160p50 HEVC yet - but ~45Mbs 1080p50 HEVC SDR 10-bit files are decoding and playing back very nicely (albeit in 8-bit)

  • Hello, i'm New to the libreelec forum.

    Running libreelec on my rpi4 for long time, works perfect.

    But would like hdr to work.

    Is it possible to update to the nightly build with hdr support and keep all my other addons and settings in kodi?

    And if possible how do I instal this nightly build ?

    And can I downgrade back to 9.2.6 if needed?

    Or is it better to take a New sd card and fresh install with latest nightly build and reinstall my addons?

    Can you make a New sd card with nightly builds with the usb-SB creator?

  • It's best to do a fresh install of the official LE 10 beta 1 release (or the latest nightly build) on a separate card and then update it with the test build (copy the tar file to the Update share via SMB or to the /storage/.update/ folder via scp and then reboot).

    Upgrading from LE 9.2 is not supported (it might work, but depending on installed addons you can end up with a real mess) and downgrading isn't supported at all (you'll definitely end up with an unusable system).

    The test builds I post here in this thread only contain a few additions that aren't in current nightly builds and if testing goes fine we'll include the changes in LE 10 / nightlies - switching from the test builds to LE10 nightlies or the next official release will work without issues.

    so long,


  • Hello, thanks for your continued work on this. This build works well so far; colours appear more accurate to my untrained eye. My TV doesn't show colorspace info, so I can't comment on that unfortunately.

  • Here's a new testbuild, now with - hopefully - correct BT.2020 YCC->RGB conversion matrix:


    noggin do you have a possibility to verify with your HD-fury if the conversion matrix is OK now? popcornmix's HDMI analyzer doesn't seem to have picture/color analysis features and visual testing is quite a PITA as I don't have an easy-to-use known-good reference to compare against (my TV's built-in player sucks, it completely exits after switching to HDMI input so I can't easily switch back-and-forth).

    Of course feedback from others is highly welcome, too!

    so long,


  • Hi Hias,

    Is this the latest build to test? And this one should be also the best to test. Am I right?

    When I download the file and unzip I see different files and maps inside. How could I write that build to sd card? Do you have some steps how it should be?

    So long

  • Is this the latest build to test? And this one should be also the best to test. Am I right?

    When I download the file and unzip I see different files and maps inside. How could I write that build to sd card? Do you have some steps how it should be?

    You need to be running a Matrix beta build.

    Copy the tar file linked to /storage/.update and reboot.

  • My HD Fury Vertex won't do that (as the RGB/YCbCr conversion matrix isn't an HDMI-signalled thing, as downstream devices don't need to know it) - but I MAY be able to grab the same Rec 2020 content via two player routes (Pi 4B vs Sony UHD BD player or AMLogic CoreElec box etc.) using a Black Magic 4K HDMI capture card if I get a chance, and then compare the results in Davinci Resolve Studio (Vector Scope images and pixel values should both be testable there).

    I'll see if I've got Rec 2020 colour bars as a file on one of my test file archives.

    ** EDIT - The EBU have their nice new colour bars in 4:2:2 v210 10-bit HLG Rec 2020 format here : EBU Technology & Innovation - Colour Bars for use in the Production of Hybrid-Log Gamma (HDR) UHDTV

    And they document the YCbCr snd RGB pixel values they should hit in the various areas in the PDF - in 10-bit (so divide by 4 for 8 bit)

    These bars are also good for checking Rec 709 SDR tone-maps using both Scene Light and Display Light conversions **

    (However BlackMagic HDMI captures from an RGB source may differ from those in YCbCr - they don't have the best reputation in this regard - and my other player may well be YCbCr native output - which is more usual for video players)

    Edited 6 times, last by noggin ().

  • Hmm - may need to check out my capture solution. I can capture 2160p25 Rec 709 Kodi menus, but the minute the Pi 4B goes into Rec 2020 HLG mode I can see an output, but Media Express (Black Magic recording application) doesn't work properly and just records audio. (The TV I'm feeding via an HDMI splitter still goes into HDR Rec 2020 mode). Will check my software version. I've captured 2160p50 Rec 2020 HLG using this set-up before - so I know it will capture and record Rec 2020 HLG stuff.