rpi4b and LG OLED C1 - cannot output 4K correctly

    I am experiencing a strange "bug" with Kodi 4K rendering on RPi4b. It did not work in LE v11, and still does not work in LE v12.

    I have LG OLED C1 and Kodi user interface set to be rendered in 1920x1080@100Hz. I have however whitelisted all 4K modes (as per wiki https://wiki.libreelec.tv/configuration/4k-hdr#id-4k-60hz) and all Full HD modes.

    Now, when playing 4K content (SDR, HEVC) the TV switches into 4K mode, but the movie is rendered in what seems to be a Full HD res (1920x1080) into the first quadrant. If I un-whitelist the 4K modes, the TV does not switch into 4K mode and the movie is again rendered in Full HD res correctly (and upsampled to 4K by TV). So it looks, like for some reason Kodi downsamples the content regardless the mode the TV is in.

    This is how it looks:

    I could have missed something fundamental in Kodi settings, but after several reviews I am still clueless. Anyone has any insight?

    Wiki says:

    Quote

    The second impact of the Kodi desktop resolution is how media is scaled. If "Adjust Refresh" is not enabled, Kodi will scale all media played up or down to the desktop resolution and refresh rate, which by default is 1080p @ 60 fps.

    So enable "Adjust Refresh".

    Under the years i have used Pi4 with LE and LG Oled something similar happened only once and it went away when i replaced the HDMIcable.

    Quote from Da Flex

    So enable "Adjust Refresh".

    "Adjust Refresh" is, following the advice in the same wiki, set to "On Start/Stop".

    Quote from chewitt

    Please share a debug log that demonstrates the problem. Thanks.

    I am currently only able to access the box remotely, so will have to see, if I could enable and replicate this somehow.

    Quote from MatteN

    Under the years i have used Pi4 with LE and LG Oled something similar happened only once and it went away when i replaced the HDMIcable.

    There is one tricky thing I did not fully realize - I am using Argon case with SSD port. I had to originally replace the board with HDMI convertors because one did not work. Then I read here that Argon cases are not very reliable with respect to HDMI. So I wonder if this might be a culprit.

    So far my reasoning about this not being the cable (or the HDMI output itself) is that apparently the TV switches into right res (4K), but for some reason Kodi turns on the downsampling anyway. I would expect if the hw negotiation of 4K mode fails, it would not switch into it in the first place.

    • New
    Quote from chewitt

    Please share a debug log that demonstrates the problem. Thanks.

    Not sure what to log I chose "video" and "video and audio timing" in "components" list. I just tried to start playing the file (which was 4K HEVC mov created by me) and when the playback started and it was obvious it was wrong I stopped it. Then I stopped the logging.

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