You are not logged in. Please login or register.
SmoothVideo Project → Using SVP → 4K on a 1080p Screen
So, I have a theoretical question. In theory at least, 4K video on a 1080p screen should be better than 1080p video, because of double chroma resolution etc. Now, since I use Kodi Dsplayer, Madvr and ffdshow with 8 bit 4:2:0 conversion would I gain any benefit?
For example Netflix shows have both 1080p and 4K versions, would any of the benefit carry through the down conversion?
4k/UHD also has the benefit of generally having much higher bit rates than the 1080p version.
I guess that's true, but I wonder if there is generally more "bitrate per pixel" if you know what I mean.
It is very difficult to see the difference between 4K and 1080p on 1080p screen.
But for SVP 4K resolution on input in 4 times hadrer to process than 1080p resolution video.
To decode 4K and to convert it to 1080p you need some more extra performance too.
So, You need to compare both cases and decide if your hardware powerfull enough and do you really see the difference?
It is my answer from practical side 
With 6700k and 1070 and test videos, performance seems to be enough. But you are right, I guess I need to test if I see any meaningfull difference.
It depends on how big your screen is... For example on a 32 inch TV or even bigger, a 43 inch TV, you'll definitely notice the difference between a 4K video being downscaled to 1080p and just a normal 1080p video. On a 27" monitor, I wouldn't say there's no point. But it's much less noticeable.
I guess that's true, but I wonder if there is generally more "bitrate per pixel" if you know what I mean.
If you wanted to look at it that way, 4k video should look better regardless due to the way chroma sub-sampling works when down-scaling video as you mentioned.
Most videos are 4:2:0 so when using 4k video there is 4 pixels per 1pixel of 1080p. So when it down-scales it results is a much better picture due to having color information for each of your 1080p pixels. (IE ends up closer to having 4:4:4 vs 4:2:0 of native 1080p video)
Edit: This video explains it quite well, and why 4k video looks better than 1080p video on a 1080p screen.
https://www.youtube.com/watch?v=kIf9h2Gkm_U
Yeah, I have to do some tesing with the same source, both 1080p and 4K. I use projector and 106' screen, so chances are there is some benefit.
I use projector and 106' screen, so chances are there is some benefit.
In that case, that last sentence is an understatement. There is definitely a BIG benefit with a 106" projector. I believe it will be a bigger difference than going from 720p to 1080p.
You need to download something from the same source to test the difference. For example; The Grand Tour episodes can be found in both 1080p (5GB+) and 2160p (22GB+).
Anim8
Thank you for good explanation about chroma subsampling.
In video I see defferent level of ringing (it is another kind of artifact not connected to resolution 4K or 1080p). And yes. If ringing is present on video then 4K-to-1080p conversion will reduce ringing artifacts.
But when I did tests with real colorspace 4:4:4 and 4:2:0 on HQ pictures I saw the difference only at specifical places of images. Usual on diagonal lines with different color. Especially red-on-blue or something.
It is because of color space 4:2:0 uses human eyes feature to see brightness and colors with different resolution.
After some testing, I guess there is a smallish benefit. On the other hand, 4K videos seem to be crashing Kodi Dsplayer for me, so not really worth it.
Wait - doesn't SVP process and output at 4:4:4?
Therefore, shouldn't you get the same 4:4:4 chroma sub-sampling regardless of whether it's SVP or the video player that's downscaling>
> doesn't SVP process and output at 4:4:4?
nope
you can get 4:4:4 from 4K YV12 only if you'll scale down to 1080p after SVP and the scaler is smart enough to not scale chroma planes (i.e. - madVR, not sure about EVR)
nope
You're right, I just did a test that confirmed it.
...that's annoying to say the least.
SmoothVideo Project → Using SVP → 4K on a 1080p Screen
Powered by PunBB, supported by Informer Technologies, Inc.