Why is USB grabber so dark with libreelec Leia (kodi 18) ? Look at the pics

  • Hi there,
    I wonder why I cannot use Hyperion for external HDMI sources with kodi 18 testbuilds on my RPi3.
    I want to use kodi Leia testbuilds, because on the latest stable release of LibreELEC (kodi 17), full 3D frame-packing heavily stutters and with new kodi 18 testbuilds it is very smooth.

    Pic of libreELEC kodi 17:

    Pic of libreELEC kodi 18:

    I would be very happy if someone could tell me, if and how this could be fixed. I cannot use the external grabber this way, because there is so much black.

  • Maybe the defaults have changed in the kernel drivers in 18 ?

    Can you use something like v4l-ctl to adjust brightness and contrast ?

    I don’t know how to do that. I am very new to Hyperion things. In libreELEC builds, apt is not included and I don’t have v4lctl (in web it’s written like this) installed. Since there is no 'dpkg', I don’t know how to show all installed packages, so I just tested with 'which'.

  • Same here. Updated to the last Kodi 18 build and the picture of the grabber is exactly like yours. Seems something changed in Kodi 18.
    I don't know how to fix it yet, but if I know a solution I'll tell you. Please tell me if you found one.

    • Official Post

    You need v4l-utils package installed afaik:


    To install that should be these commands run from the Libreelec SSH shell:

    sudo apt-get update
    sudo apt-get install v4l-utils

    afterwards v4l-ctl will be present as that is part of the utils :)

    As to the cause I'm not entirely sure, best guess:

    - Default brightness / gamma changed in LibreElec test build for grabbing devices which v4l-ctl can correct but not ideal.
    - Kodi 18 defaults to 10bit and doesn't play nice with 8bit readouts (losing brightness as a result)

    • Official Post

    Hmm could have sworn it wasn't that limited under OpenElec where it's based on, then you are probably out of luck testing this via command line sadly.
    Raspbian with Kodi install might work better if you want to test it out on a spare MicroSD card for instance.

    LibreElec does list the utils in their repo so possible to install just not clear how.

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