[RPi5] 4K/60Hz on LibreELEC 12.0.1

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    I was beating my head against a wall trying to get my system to go to 4k 60hz mode -- but I finally found a solution (I think).

    I'm running a Rpi5 with LibreELEC 12.1. Its HDMI port connects to a Yamaha RX-A740 receiver, which in turn connects to HDMI Port 2 on my Samsung UN75TU7000 TV. That port has "Input Signal Plus" enabled. The TV correctly detects the receiver on that port. However, the Kodi settings did not offer any 4K refresh rate higher than 30hz. Same in the Kodi Whitelist settings -- no 3480x2160 refresh rate above 30hz shown. I have the TV in "Movie" mode (with additional tweaks), which yields the best picture quality.

    Today, I connected the Rpi5 HDMI port directly to the TV's HDMI Port 2. Immediately, the TV detected it as a "PC". When I opened the TV settings, the only modes offered were "Entertainment" and "Graphic" -- but I want "Movie" mode. Going back to Kodi, though, I now saw the 60hz option available -- so I whitelisted it and changed the refresh rate.

    Then, I reconnected the Pi through the receiver, as per normal. The refresh rate stayed at 60hz, even across a boot. It disappeared as an option in the Whitelist settings, but that doesn't seem to have mattered. (Unless Kodi is showing 60hz, but really using 30hz....?)

    Hope this helps someone in the same situation.

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    Quote from rkershenbaum

    Then, I reconnected the Pi through the receiver, as per normal. The refresh rate stayed at 60hz, even across a boot. It disappeared as an option in the Whitelist settings, but that doesn't seem to have mattered. (Unless Kodi is showing 60hz, but really using 30hz....?)

    Theory: Your EDID was updated during your direct RPi - TV connection. Now your current RPi - AVR - TV setup keeps that setting.

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    Quote from Da Flex

    Theory: Your EDID was updated during your direct RPi - TV connection. Now your current RPi - AVR - TV setup keeps that setting.

    Maybe...but when I go to the Whitelist settings, 3480x2160 60hz is no longer available there -- even though the 4k 60hz setting stayed selected in the main display settings menu.

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    Quote from rkershenbaum

    Maybe...but when I go to the Whitelist settings, 3480x2160 60hz is no longer available there -- even though the 4k 60hz setting stayed selected in the main display settings menu.

    I think the whitelist is loading HDMI modes from the current display, but the older EDID is still in use. Probably your AVR is old, and has a problem with 4K modes.

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    Quote from Da Flex

    I think the whitelist is loading HDMI modes from the current display, but the older EDID is still in use. Probably your AVR is old, and has a problem with 4K modes.

    Could be. The receiver is, I think, a 2014 model. However, the specs say:

    This model will support HDMI 2.0 connectivity. It supports 4K Ultra HD 50 Hz/60 Hz signal pass-through to output motion-smooth high definition videos.

    It also supports RGB, YCbCr 4:4:4, YCbCr 4:2:2 as well as YCbCr 4:2:0 video signal for more vibrant and lifelike images.

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    Another issue could be the HDMI cables. If one of them isn't HDMI 2.0 / 2.1, then it might be the bottle neck, and 4K modes aren't offered anymore. So check the HDMI cable standards.

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    Quote from Da Flex

    Another issue could be the HDMI cables. If one of them isn't HDMI 2.0 / 2.1, then it might be the bottle neck, and 4K modes aren't offered anymore. So check the HDMI cable standards.

    I'm ordering some new cables. I'll report back on the results.

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    Quote from MatteN

    Wiki says: "Raspberry Pi 4/5 boards notably do not support 4K60 4:2:0 output."

    I'm not finding anything in the TV's specs about that. But Kodi did show the 4k60 option when the Pi was plugged directly into the TV (although that caused the TV to detect it as a PC, and eliminate the "Movie" mode).

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    MatteN is probably on the right track with his answer. Remove EDID captures and connect the RPi4 board directly to the TV until you get things working. You probably need to experiment with different TV ports and/or port settings to ensure it can accept 12-bit 4:2:2 input, which is what the RPi board uses when 10-bit YUV 4:2:0 (which it cannot output) is needed by media.

    See https://wiki.libreelec.tv/configuration/4k-hdr#id-4k-60hz

    Note that RPi4 (not RPi5) also requires 4K modes to be enabled in config.txt. You do not want to force the Kodi desktop to 4K60 unless you want the UI to be slow and annoying. Mode switching for playback is fine, but the UI is best in 1080p.

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    Only one port on my TV uses ARC, so I'd need to use that port if I connect the Pi directly. Also, the TV detects it as a "PC" and restricts the calibration options I can use. There may be a way to circumvent that, but I haven't found it. (Anyone with a Samsung TV know?)

    I'll try new cables first, when they arrive, and report back.

    In the meantime, I found the recommended settings in the LibreELEC Wiki, and applied them:

    https://wiki.libreelec.tv/configuration/4k-hdr

    Most of my content is 1080p, so that's what the Pi is now sending to the TV, and the TV is doing the 4k upscaling. I don't even know if I have any 4k 60hz content. So all is good for now (but I do want to see what happens with the new 4k-certified cables).

    Thanks to everyone for the comments and suggestions!

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    ARC is only necessary for the connection TV -> AVR/soundbar, to provide the sound from TV back to the sound system via HDMI. So reserve that port for your AVR, if it also supports ARC. Your RPi doesn't use that kind of connection, so you could use another HDMI as well.

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    Quote from HarryH

    ARC is only necessary for the connection TV -> AVR/soundbar, to provide the sound from TV back to the sound system via HDMI. So reserve that port for your AVR, if it also supports ARC. Your RPi doesn't use that kind of connection, so you could use another HDMI as well.

    That makes sense. To switch to a different device (e.g. Bluray player) we'd need to switch both the TV and AVR inputs. We could probably live with that, since we do it only rarely.

    The bigger problem is that the TV detects the Pi as a "PC" when it's directly connected. I've found TV calibration settings that greatly improve the picture quality, but those aren't available in "PC mode". I haven't found a way around that.

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    Quote from HarryH

    Maybe this dirty hack is the only option:

    https://eu.community.samsung.com/t5/tv/turn-off…ut/td-p/7626071

    Do you have already checked, if you maybe can disable the auto detection and preset/force the mode to "Standard" (non PC mode) of the HDMI port before you connect the HDMI cable? Some Samsung TVs are said to have this option.

    Good thought. But the port doesn't even appear in the "Source" menu until a device is plugged into it. So I don't see any way to set the port to "Standard".

    Apparently, they've tried to make these TVs idiot-proof, but that comes with restrictions.

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    Quote from chewitt

    You probably need to experiment with different TV ports...

    I think you should try that. We have reports on the forum that different HDMI ports act differently. Usually the first HDMI port of the TV is the most capable one.