Please excuse me if this was already properly discussed, but I just couldn’t find this kind of topic.
So my question is - should we try to match the color subsampling (4:4:4, 4:2:2 or 4:2:0) and the bit depth (8bit, 10bit, 12bit) of the video signal output, in kodi settings - as close to the source file as possible? Or there is no difference if an 8bit 4:2:0 file is being output over 8bit 4:2:0 signal or 12bit 4:4:4 signal?
I use CoreELEC 21 on a Homatics Box R 4K Plus box, and if I leave the settings for subsampling and bit depth on auto, my tv (LG C1) displays that it is getting a 12bit 4:4:4 signal, so I wonder if I should change anything about that depending on the file - to get the best results, and if the signal needs additional processing in this way, I would like to leave as much of that as possible for the tv
Technically everything should ideally be matched to ensure the best quality output and to avoid needless conversion / increase in signal bandwidth. So, a standard HD file should be output at 8-bit 4:2:0, 4K at 10-bit 4:2:0, Dolby Vision at 12-bit 4:2:2, and I guess the UI at 8-bit 4:4:4.
Team Kodi member fritsch used to be a big proponent of this and, I know, got it working perfectly years ago… but then I noticed at some point that everything just started outputting 12-bit 4:4:4 constantly. Upconversion is generally lossless, but also technically unnecessary. I’m not sure whether any attention is being paid to something that’s probably placed more in “perfectionist” territory, but I was always drawn to Kodi because of the purity of its output.
Thank you for your reply. I would actually prefer to match everything to the source file as much as possible. But I encountered a problem when outputting 4:2:0 signal to my LG C1 tv - the tv does not display this signal… And since forcing 4:2:0 output requires two steps to be applied - changing to 4:2:0 and changing the resolution - I get stuck with no signal, because after the countdown the resolution is reset, but subsampling remains 4:2:0, which the tv doesn’t display. So I have to reinstall CoreELEC, or use a backup of it. Will have to investigate further to hopefully make this work.
Edit: Hm, found this post, so I guess for movies that are mostly 24 fps - setting 4:2:0 is not possible, so only resolution, fps and bit depth can be matched with source.
