Question: 1080p/4K upscaling

BallerShotCaller · November 14, 2022 at 1:00 PM

I just found this Wiki entry which explains a lot of 4K related stuff in Kodi. Very nice!

But what I'm curious about is what is mentioned here:

Why is it recommended to let Kodi do the upscaling to 1080p when the TV can do it too?

I mean, I see the point of setting the desktop to 1080p, but for movie/TV stuff, as also mentioned in the Wiki, most 4K capable TVs should do the upscaling much better than Kodi.

So why even let Kodi do the upscale to 1080p and not passing through everything to the TV, including SD sources?

Can someone please explain a little deeper?

Thanks!

**HiassofT** · November 14, 2022 at 1:32 PM

It depends.

I usually whitelist 720p, too, so my TV (LG 55C8) does the upscaling.

But whitelisting SD has several drawbacks:

First of all GUI overlays, subtitles etc will then be rendered at a low resolution and look very ugly.

For SD material there's also the anamorphic problem, where pixels aren't square and kodi doesn't handle that too well and kodi doesn't signal 4:3/anamorphic 16:9 to the TV.

Lastly my TV has the annoying behavior of always cutting off overscan in SD resolution so parts of the GUI are missing.

If you can live with the limitations you are free to enable SD output but it's a lot more hassle free to just let kodi upscale SD to HD.

so long,

Hias

frakkin64 · November 14, 2022 at 4:31 PM

My personal reason for why I don't whitelist < 1080p is: refresh rate switching is slow, usually a ~2 second delay where the TV is black during the start of the video. And Kodi upscaling seems to take literally no effort on the CPU/GPU.

**jernej** · November 14, 2022 at 6:33 PM

Quote from frakkin64

And Kodi upscaling seems to take literally no effort on the CPU/GPU.i

That's true when using DRMPRIME rendering, which is default for all boards except Generic (I think). DRMPRIME renderer uses DRM planes for video rendering, which are implemented via dedicated HW blocks inside display pipeline. So this is basically the third option, which is actually more common than GPU scaling on ARM boards and most efficient too. Usually there is little to no scaling options in HW, so quality is what it is.