Arstidir Just set this up on my C1 after years of messing around with hardware grabbers that never produced a totally satisfactory solution.
Rooting and installing PicCap couldn't be easier if it tried and you can be safe in the knowledge that anything you do is easily reversible. No coding, no SSHing in, nothing more than opening an app from the LG Home menu and once you have it working you never need to return to it. Only issue I found was finding the right resolution to use but an earlier post here had the right one to use and after that it literally just works.
I'm currently running Hyperion on a PiZero W directly connected to the APA102 strip from my past efforts, I needed to change nothing in the settings as, again, it just works. My next step is to replace the Pi Zero with a Sonoff Basic running WLED, so I can easily power the LEDs power supply on and off and cut out the reliance on SD cards etc, and then temporarily run Hyperion on my server until I'm Happy with running it on my C1. Installing Hyperion itself on the TV does involve a bit of mucking about currently but I'm sure it will be made much simpler soon given what they did with PicCap so don't let that put you off.
These developments have made things so easy it's crazy all the hassle people used to go through with mountains of cables and boxes velcroed to the back of their TVs to end up with a much less than perfect system.
The only provisos in this are...
1. LG could spoil the fun with a firmware upgrade BUT the devs have cracked every change so far, mine is running the latest firmware, and worst come just stick with the current version.
2. It works fine with live broadcast TV but doesn't work with the internal video apps, ie Netflix etc. However, it works perfectly if you use an external device for streaming, ie FireTV Stick, Shield, ATV etc etc.