[SOLVED] Poor image quality of IPS LCD when playing youtube video under Windows

[modeonoff]

Hello, I bought an external 4K IPS LCD display for my Windows PC. When I played the following video along side with a M1 MacBook Pro 16", I noticed that during 1:18-1:19, when the background was dark, black blocks showed up on the new display and the image quality looked very bad. To test if it is Windows or the display's problem, I connected the new display to the MacBook Pro and replayed the same video under mirror mode. such ugly poor image quality disappeared.

View: https://www.youtube.com/watch?v=w4SlU_nmfUA


What is the reason for the poor image quality when playing the same movie on a Windows PC? Can it be fixed?

Also, when playing the same video when connected to the Mac in mirror mode, the M1 MacBook Pro showed completely black background while the new LCD showed background that just looked dimmed (kind of like a semi-transparent dark cloth with light shining from behind). Is this normal? Is it caused by shortcoming of IPS panel vs. mini LED technology?

 

[lvt]

What is your Internet speed?

Did you select the higher video resolution in Youtube (for example 1080p) ?

 

[modeonoff]

My internet speed is 5mbps. I don't think it is an issue because the image quality issue disappeared when I connected the new display to a MacBook Pro. Also, no such issue when playing the same video on the Mac and iPad Pro.

Yes, I chose the highest video resolution which is 4K.

 

[lvt]

My internet speed is 5mbps. I don't think it is an issue because the image quality issue disappeared when I connected the new display to a MacBook Pro. Also, no such issue when playing the same video on the Mac and iPad Pro.

Yes, I chose the highest video resolution which is 4K.

So the image quality issue only happens with the Windows PC.

What is the name of your display? Does your display have an auto adjusting function, or you can select different modes like scenery, game or movie...?

 

[USAFRet]

My internet speed is 5mbps. I don't think it is an issue because the image quality issue disappeared when I connected the new display to a MacBook Pro. Also, no such issue when playing the same video on the Mac and iPad Pro.

Yes, I chose the highest video resolution which is 4K.

youtube adjust the resolution depending on your download speed.

A slow connection gets a lower resolution. Their thought is....a smooth lowres video, rather than a choppy hires video.

What do you mean by "external monitor" ? How is this connected?

 

[modeonoff]

So the image quality issue only happens with the Windows PC.

What is the name of your display? Does your display have an auto adjusting function, or you can select different modes like scenery, game or movie...?

youtube adjust the resolution depending on your download speed.

A slow connection gets a lower resolution. Their thought is....a smooth lowres video, rather than a choppy hires video.

What do you mean by "external monitor" ? How is this connected?

Youtube shows "Auto 2160p 4K". Tried USB-C and HDMI connections.

 

[modeonoff]

So the image quality issue only happens with the Windows PC.

What is the name of your display? Does your display have an auto adjusting function, or you can select different modes like scenery, game or movie...?

Actually there are two types of image issues here. The first one is what I described in the original post. When connected to a Windows PC, I can see blocks of pixels in dark background. When connected to a Mac, no such block of black pixels.
Tried two displays already. Same thing. One is LG27UP650W 27" 4K and the other is Cocopar 17" 4K.

Another image issue I have is that dark black is dark black on Apple devices but on those two displays mentioned above, they are not dark black. Is it because they are IPS panel while the Mac uses other technology?

 

[Glenwing]

The blocks are compression artifacts. They are part of the video. Whether they are visible or not is just down to the calibration of the panel and how the manufacturer has chosen to distribute those shades. In some monitors the dark shades are spread further apart because it gives a "competitive advantage" in gaming by allowing slight differences in dark areas to be visually distinguished. But it is not ideal for image quality. Usually this is adjustable in a monitor setting like "black boost" or "shadow boost" or something similar. It may also just be a result of poor color performance, not necessarily intentional, in which case there may be no menu options for adjustment. You can try different picture modes on the monitor and see if they are different. You can also test how far apart/visible each shade of black is here: http://www.lagom.nl/lcd-test/black.php

Why it shows up on Windows but not on mac is hard to say. If you're connecting to a different port on the monitor, different ports may have different default picture settings in the monitor menu. It's also possible Windows is messing with the image, if HDR is enabled, or other things, depending on what options are enabled.

 

[modeonoff]

The blocks are compression artifacts. They are part of the video. Whether they are visible or not is just down to the calibration of the panel and how the manufacturer has chosen to distribute those shades. In some monitors the dark shades are spread further apart because it gives a "competitive advantage" in gaming by allowing slight differences in dark areas to be visually distinguished. But it is not ideal for image quality. Usually this is adjustable in a monitor setting like "black boost" or "shadow boost" or something similar. It may also just be a result of poor color performance, not necessarily intentional, in which case there may be no menu options for adjustment. You can try different picture modes on the monitor and see if they are different. You can also test how far apart/visible each shade of black is here: http://www.lagom.nl/lcd-test/black.php

Why it shows up on Windows but not on mac is hard to say. If you're connecting to a different port on the monitor, different ports may have different default picture settings in the monitor menu. It's also possible Windows is messing with the image, if HDR is enabled, or other things, depending on what options are enabled.

Are you talking about HDMI ULTRA HD Deep Color mode? So I should try different types of ports and also test when HDR is on or off? In general, given a choice of DisplayPort, USB-C and HDMI, which is the best port to use?

How come the MacBook Pro and iPad can display solid black but when playing the same images, other IPS LCDs show some kind of light at the back. Kind of like back light behind a semi-transparent screen curtain. Is it because of the way Apple calibrates their displays or is it because of difference in panel type? Is mini LED better than IPS in this regard?

 

[modeonoff]

The blocks are compression artifacts. They are part of the video. Whether they are visible or not is just down to the calibration of the panel and how the manufacturer has chosen to distribute those shades. In some monitors the dark shades are spread further apart because it gives a "competitive advantage" in gaming by allowing slight differences in dark areas to be visually distinguished. But it is not ideal for image quality. Usually this is adjustable in a monitor setting like "black boost" or "shadow boost" or something similar. It may also just be a result of poor color performance, not necessarily intentional, in which case there may be no menu options for adjustment. You can try different picture modes on the monitor and see if they are different. You can also test how far apart/visible each shade of black is here: http://www.lagom.nl/lcd-test/black.php

Why it shows up on Windows but not on mac is hard to say. If you're connecting to a different port on the monitor, different ports may have different default picture settings in the monitor menu. It's also possible Windows is messing with the image, if HDR is enabled, or other things, depending on what options are enabled.

I know that some monitors have more color modes. Under some of those modes, there is no ugly pixelated blocks. Could this be that those monitors have wider color gamut and/or color temperature ranges?

 

[modeonoff]

The blocks are compression artifacts. They are part of the video. Whether they are visible or not is just down to the calibration of the panel and how the manufacturer has chosen to distribute those shades. In some monitors the dark shades are spread further apart because it gives a "competitive advantage" in gaming by allowing slight differences in dark areas to be visually distinguished. But it is not ideal for image quality. Usually this is adjustable in a monitor setting like "black boost" or "shadow boost" or something similar. It may also just be a result of poor color performance, not necessarily intentional, in which case there may be no menu options for adjustment. You can try different picture modes on the monitor and see if they are different. You can also test how far apart/visible each shade of black is here: http://www.lagom.nl/lcd-test/black.php

Why it shows up on Windows but not on mac is hard to say. If you're connecting to a different port on the monitor, different ports may have different default picture settings in the monitor menu. It's also possible Windows is messing with the image, if HDR is enabled, or other things, depending on what options are enabled.

You are right. Tried several displays. Apple devices have no such issue. For some monitors from other brands, such problem sometimes disappeared after I changed the color mode.

By calibration of the panel and how the manufacturer has chosen to distribute those shades, does that has anything to do with color gamut?

 

[Glenwing]

You are right. Tried several displays. Apple devices have no such issue. For some monitors from other brands, such problem sometimes disappeared after I changed the color mode.

By calibration of the panel and how the manufacturer has chosen to distribute those shades, does that has anything to do with color gamut?

Not really, it is related to contrast and color accuracy (∆E), but mainly it is just a matter of how the manufacturer has configured the monitor, not something you can determine directly from the physical specifications.

 

[modeonoff]

Not really, it is related to contrast and color accuracy (∆E), but mainly it is just a matter of how the manufacturer has configured the monitor, not something you can determine directly from the physical specifications.

Thank you