[mythtv-users] My experience setting up a NUC 11

[Justin Moore]

I just went through the process of setting up MythTV on a NUC 11 PAHi5
running Ubuntu 20.04 LTS, and wanted to share some of the pain points I ran
into in case anyone else is trying to do the same.

https://ark.intel.com/content/www/us/en/ark/products/205040/intel-nuc-11-performance-kit-nuc11pahi5.html

1. Getting IR to work
There's a BIOS setting to enable/disable the IR receiver. If this is
unchecked -- mine was my default -- you won't see your receiver, and
ir-keytable will tell you there's no IR receiver available. Make sure to
enable it in the BIOS.

If you're using inputlirc make sure to use a udev rule to create a uniquely
named symlink. E.g., in /etc/udev/rules.d/10-persistent-ir.rules have:
KERNEL=="event*",ATTRS{name}=="ITE8708 CIR
transceiver",SYMLINK="input/irremote"
And retrigger the udev processing. Otherwise if you have a keyboard
attached and you try and use it, you'll get double key presses.

2. Getting sound to work
I couldn't get it working out of the gate. Apparently it is (was) a common
issue:
https://community.intel.com/t5/Intel-NUCs/NUC-11-Performance-No-audio-on-any-Ubuntu-based-OS/m-p/1277346
I installed the linux-image-oem-20.04d package (kernel 5.14.0-1018-oem) and
booted into it. That fixed the sound issue.

3. Getting video to work on a 4k display
https://askubuntu.com/questions/1364236/4k-graphics-problems-with-intel-nuc11-with-ubuntu-20-04-lts
My NUC runs through a Denon receiver and into a 4k TV. All the hardware and
cables should support 4k at 60fps, but my screen was going blank every time I
tried to go above 1920x1080 at 60fps. It turns out that by default Ubuntu will
use the maximum possible color depth, which in my case was 12. 4k at 60fps @
12 bits is above the maximum data rate for HDMI 2.0:
https://wiki.ubuntu.com/DeepColourDepthSupportPlan
https://en.wikipedia.org/wiki/HDMI#Refresh_frequency_limits_for_standard_video
(uses 8 bits, so multiply by 1.5 to get 12 bit data rate)
Once I set the bit depth to 8, it started working again:
https://www.soi.pw/posts/10-bit-color-on-ubuntu-20.04-with-amdgpu-driver/

4. [unsolved] Getting 1920x1080 at 24 fps video to not tear
I have a bunch of movies in my video directory, and for the life of me I
couldn't get them to play without tearing when I was driving my video
display at 4k. I tried the "TearFree" option but it looked like this, and
playback kept blacking out:
https://i.stack.imgur.com/gDOkX.jpg
I also tried various combinations of DRI3, triple buffering, and Wayland,
but none of those seemed to work.

Ultimately I set my desktop and display to 1920x1080 at 120Hz@8bits and that
seems to have solved the tearing problem. I don't have a bunch of 4k
content but I was hoping to have this NUC be my future-proofed 4k at 60fps and
full surround sound system. It's ... mostly there, but not fully.

Hopefully this email is useful to anyone looking to get a NUC 11 system as
a frontend, and if anyone figures out how to get 24fps video to not tear
I'd be thrilled. :)

Thanks to all the MythTV devs who have made this an awesome system over the
years!
-justin
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