Do 4K and 5K iMacs uncover the existing flaws in 1080p video? Or is it a sampling issue due to fractional/uneven scaling?

[staypuftforums]

On day 2 with the 2019 4K iMac and still on the fence on whether I'm going to keep it or not. A few notes:

1) The 5400 spinner is a non-issue. Yes, starting up the computer is incredibly slow (several minutes) and it takes 5 seconds instead of 1 second (SSD) to open an app for the first time, but other than that I don't notice much difference at all.

2) The screen is quite a bit less bright than I was expecting. It's currently on 13/16 (81%) and this is in a fairly dark room.

3) Text and 4k video are beautiful, (night and day difference compared to low resolution monitors) but 1080p video is actually a step down compared to my 1080p monitor. Is this because of uneven scaling due to the 4K iMac's weird resolution (3840x2160 could be scaled at 2x) or is the iMac just exposing the inherent "low res" of 1080p video?

 

[ignatius345]

What video source are you watching?

 

[staypuftforums]

What video source are you watching?

Most noticeable difference is on YouTube. 4K videos (very sharp) look similar to what 1080p videos look like on my 1080p monitor.

In addition to subpar quality, I’d swear it was a 30 Hz display. Motion just looks off. Again, most noticeable on YouTube.

With text there is no comparison. The 4K display is excellent there.

 

[06tb06]

My last Mac was the 2017 iMac 4K BTO and, I could be wrong, but didn't Apple limit the 5400-rpm drives to the base model 1080p iMac?

 

[staypuftforums]

My last Mac was the 2017 iMac 4K BTO and, I could be wrong, but didn't Apple limit the 5400-rpm drives to the base model 1080p iMac?

2019 4K iMac has a 1TB 5400 spinner.

 

[ignatius345]

Most noticeable difference is on YouTube. 4K videos (very sharp) look similar to what 1080p videos look like on my 1080p monitor.

In addition to subpar quality, I’d swear it was a 30 Hz display. Motion just looks off. Again, most noticeable on YouTube.

With text there is no comparison. The 4K display is excellent there.

I wonder if it's just showing off funky upscaling? I would imagine that if you could scale a 1080p video to exactly double the width, it would be cleaner (1 pixel becoming exactly 4 pixels) versus some arbitrary scaling that might show off artifacts more.

 

[staypuftforums]

I wonder if it's just showing off funky upscaling? I would imagine that if you could scale a 1080p video to exactly double the width, it would be cleaner (1 pixel becoming exactly 4 pixels) versus some arbitrary scaling that might show off artifacts more.

It has a really weird look to it. Best description would be "washed out and soft". Like someone smeared vaseline on the camera lens before filming. YouTube thumbnails look incredible though.

 

[Fishrrman]

I have a 2018 Mini and a 1080p 27" display.

I've noticed something that doesn't seem logical on its face. That is:
If I go to YouTube and start watching a video in "HD" (1080p)
and
If the video is actually offered in higher resolutions (say, 1440p and 4k)
that
If I switch the resolution to 1440p, the video actually looks much better, even though my display is only 1080p.

My understanding is that YouTube's presentation of "1080p" is of a quality somewhat "less than" true 1080p. I could be wrong.

 

[ThunderSkunk]

Youtube. Highly compressed lo-fi content. You get what you pay for.