HDMI output signal: RGB and not YCbCr

  • I have a a Pi5 with libreelec.
    The hdmi output varies on rgb 8bit to rgb 12bit depending on the media file (1080p sdr, 4k hdr etc).
    I also have a amlogic box with coreelec, and is always displaying YCbCr 4:4:4, that is better?


    How can i change to YCbCr 4:4:4?
    I tried hdmi_pixel_encoding=4 on config.txt and nothing changes.


    May u guys help me?

  • HDMI settings don't work anymore at config.txt. The new approach is something like that:

    larslunte
    March 18, 2024 at 6:59 PM
  • The hdmi output varies on rgb 8bit to rgb 12bit depending on the media file (1080p sdr, 4k hdr etc).
    I also have a amlogic box with coreelec, and is always displaying YCbCr 4:4:4, that is better?

    No. As composition (e.g. combining subs or OSD items) happens in RGB space, there is no benefit in picture quality converting back to YCbCr before driving over hdmi.

    For 10-bit output at 4Kp60, it is necessary to output YCbCr 4:2:2, so we switch to that automatically.

  • No. As composition (e.g. combining subs or OSD items) happens in RGB space, there is no benefit in picture quality converting back to YCbCr before driving over hdmi.

    For 10-bit output at 4Kp60, it is necessary to output YCbCr 4:2:2, so we switch to that automatically.

    Thanks my friend. But when I play 4k remux, the libreleec outputs rgb. thats normal?

  • Thanks my friend. But when I play 4k remux, the libreleec outputs rgb. thats normal?

    As I said

    Quote

    For 10-bit output at 4Kp60, it is necessary to output YCbCr 4:2:2, so we switch to that automatically.

    At resolutions or refresh rates below that we will output the RGB directly.