HD vs 4K for YouTube Uploading

[dellsam34]

We all know that uploading SD video files to YT has been a joke for quite some time now, This is why I started resizing to HD before uploading, However we are at it again with another similar scenario where even HD is not important for YT algorithms anymore, 4K files will get special treatment of VP9, but I think there is more to it than just VP9, It looks like even AVC1 HD files are more compressed than it use to be, But let's assume this is not true and just focus on 4K VP9 vs HD AVC1.

I keep saying 4K and I know it's the wrong name as 4K has a slightly different resolution, It should be called UHD, but just calling it 4K for the sake of public understanding.

I've uploaded two identical captures, One was de-interlaced and resized to 1440x1080 and uploaded as such (lossless HuffYUV), The second link is the one that was also de-interlaced and resized to 2440x2160 and uploaded as such as well, Please feel free to discuss and analyse, any opinion is greatly appreciated.:

HD upload:
https://youtu.be/8f57a_ouoYo

4K upload:
https://youtu.be/SIwhelThKoE

I want to point out that I'm aware that all this resizing means nothing to the original SD master files (even if they are broadcast quality) when played back locally or shared in other ways besides the streaming platforms, I'm just focusing on the mainstream sharing platforms, specifically YouTube and discuss ways to improve the visual quality of a shared video file from when it leaves the hard drive to when it reaches the other end of the screen. I don't want people to think I'm trying to make VHS look like IMAX, I'm not. So please avoid this discussion.

Now uploading resized 4k files in long lengths is challenging in terms of file size, So an encode is a must, I would also like to discuss ways of how to encode these 4k files before uploading, Script, NLE, Hybrid ...etc, Anything in your mind.

[lollo]

For what is worth and with a quick check, I see that the HD and 4K video looks very similar in term of image quality (fixed frame). Maybe the 4K frame is a little bit sharper. I had to resize the HD frame to 4K with nnedi3_rpow2(rfactor=2, nns=4, qual=2): https://imgsli.com/MzA5MTk0

You could also try the opposite, downscaling the 4K to HD and compare.

In term of motion quality, I do not see any major difference.

For uploading, if you remember our old discussions, we found that, although HuffYUV is referable, if you compress with h264 (HD) or h265 (4K) using a low CRF there is not much penalty in quality (YT further compresses anyhow).
Be careful with ColorMatrix parameter specific for HD and 4K (Rec.709 and Rec.2020)

[Alwyn]

This rule has applied for at least two years: Any video 1440 or higher gets VP9. Below 1440 gets H264.