Youtube add their own sharpening?

[Snowbro]

Uploaded a 4k video, it was shot at 0 sharpness, I added just +8 in premiere. h.264 looks amazing, it looked fine last night after it uploaded to private. Now today when I view it in the browser on anything but fullscreen, it looks like over sharpened garbage. Looks fine on my phone at 1440p. Does their compression do something weird, or add sharpening? It could be their media player in a non-fullscreen mode idk. I have only had this happen on their player when you smash a 4k video into a very small size, this is something new. My other 4K videos havent had this issue. 

[newfoundmass]

Are you watching the 4k stream windowed? That might be why, though I haven't had that problem in years. 

[Snowbro]

Full screen looks fine, theatre mode at any size looks like no aliasing is present. I usually don't add any sharpening because its 4k and looks sharp enough; I read something that said youtubes conversion can make jaggies if you added sharpening in post. I don't like unsharp mask, but I used a tiny bit in an older video with no problems, this time I just did +8 sharpening, it honestly didn't look much different even zoomed in. 

[hmcindie]

Yes, youtube does a shitty downscale that gives 10x more aliasing to 4k material when viewed under the 4k size.

That's also a good reason why those 4k vids look so "sharp" when watched on a 1080p screen.

[Mokara]

9 hours ago, hmcindie said:

Yes, youtube does a shitty downscale that gives 10x more aliasing to 4k material when viewed under the 4k size.

That's also a good reason why those 4k vids look so "sharp" when watched on a 1080p screen.

If you watch 4K on a smaller screen, it is your computer/device that is doing the downscaling, not YouTube. No sharpness is being added. It looks high resolution because it is high resolution. 

[webrunner5]

Speaking of downscaling. Interesting way to figure out if it is downscaling if you can find the true specs.

"Figuring out what kind of monitor you’ve got requires a trip to your monitor’s spec sheet. Proper QHD monitors have a larger pixel pitch or pixel width (the distance between the center of two sequential pixels) compared to 4K UHD monitors. If your QHD monitor has a pixel pitch of .233mm or so, then you’re working with the real deal. If it’s got a 0.16mm pixel pitch, the same as a UHD monitor, you’re probably working with a downscaled display. Eagle-eyed owners can likely confirm their suspicions by looking at text or small icons, but you should probably contact your manufacturer to get some clarification".

[hmcindie]

On 11/15/2018 at 10:59 AM, Mokara said:

If you watch 4K on a smaller screen, it is your computer/device that is doing the downscaling, not YouTube. No sharpness is being added. It looks high resolution because it is high resolution. 

Shitty downscaling increases aliasing -> increases hard edges -> looks "sharper". Playing stuff in a browser usually means shitty downscaling. Youtube is played in a browser. 

Those edges of the buildings (and hard lines) will start flickering and aliasing when played in 4k with a 1080p screen.

 

[Mokara]

58 minutes ago, hmcindie said:

Shitty downscaling increases aliasing -> increases hard edges -> looks "sharper". Playing stuff in a browser usually means shitty downscaling. Youtube is played in a browser. 

Those edges of the buildings (and hard lines) will start flickering and aliasing when played in 4k with a 1080p screen.

 

All youtube does in generating the lower res versions is combine the pixels, so 4 pixels becomes one in 4K > FHD. They are not going to spend extra computational resources to do anything else. If you have a deliberately soft image it will lose that when downscaled. More problematic is that it will be re-encoded again after that, which will introduce a whole bunch of artifacts. 

For best results on a 1080p panel you should view the 4K version and let your computer do the down conversion, that way you will get the pixel remapping only, without the re-encoding artifacts, and get a much better image than if you viewed the 1080p version.

[hmcindie]

8 hours ago, Mokara said:

All youtube does in generating the lower res versions is combine the pixels, so 4 pixels becomes one in 4K > FHD.

Nothing you say is relevant to the OP.