Screen Blinking/Flicker Issue On Focus Loss

Aminy · 03-24-2025, 05:59 AM

Hi, when using the full screen viewer and alt tabbing to my second monitor the calibre program flickers black for less than half a second before going back to normal. This issue happens whether I click onto calibre or click out of calibre/alt tab into or out of calibre while in full screen. While not in full screen the program doesn't have this screen blinking issue.

Steps I've taken to solve this problem:

Look in settings to see if this is an optional setting.

Updating Calibre, I went from version 7 something to current version 8.0.1

Updating Nvidia drivers, from version 572.70 to latest.

Tried to reproduce the issue in other applications, but this problem seems to be only in calibre. Other programs do not cause this issue when alt tabbing.

More info:

I have an extremely old version of Calibre 3.16 that doesn't have this same problem.

I tried to screen capture this issue, but this blinking doesn't show up on the screen recording through OBS.

kovidgoyal · 03-24-2025, 06:45 AM

That's an interaction between your GPU drivers an Qt webengine which is what the viewer uses. You can try disabling hardware rendering it might help, as described here:

https://doc.qt.io/qt-6/qtwebengine-debugging.html

Aminy · 03-24-2025, 08:19 AM

Thank you for the quick reply. I spent a long time trying to learn how to disable hardware rendering, I found this old thread https://www.mobileread.com/forums/sh...d.php?t=327243 that gave some more direction.

I'm not very tech savvy, so I don't know how to use cmd or add in element variables. I followed the "how to setup environment variables" through one of the links, is this what the environment variable suppose to look like?

edit: image doesn't load for me so here is the link https://i.imgur.com/QhoLLIx.png

Aminy · 03-24-2025, 08:35 AM

I think my reply message got deleted somehow, but I'll post again just in case. Sorry, if it's spam.

I tried applying the environment variable to disable gpu hardware acceleration and the problem is still persisting. ( I did restart my computer after applying environment varible)

More info: g-sync is turned off on nvidia options, Hardware-accelerated GPU scheduling in windows display settings is turned off.

Thank you again for the quick reply.

kovidgoyal · 03-24-2025, 09:24 AM

Then I'm out ideas, sorry.

JSWolf · 03-24-2025, 04:02 PM

Quote:

Originally Posted by Aminy

Thank you for the quick reply. I spent a long time trying to learn how to disable hardware rendering, I found this old thread https://www.mobileread.com/forums/sh...d.php?t=327243 that gave some more direction.

I'm not very tech savvy, so I don't know how to use cmd or add in element variables. I followed the "how to setup environment variables" through one of the links, is this what the environment variable suppose to look like?

edit: image doesn't load for me so here is the link https://i.imgur.com/QhoLLIx.png

Get rid of the path for your Qt environment variable and add in the quotes.

Code:

QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"

jmurphy · 03-25-2025, 12:37 PM

[QUOTE=JSWolf;4500144]Get rid of the path for your QT environment variable and add in the quotes.

We covered this: QT is QuickTime.
What you are trying to say is: Qt

Stop poisoning the search engines.

JSWolf · 03-26-2025, 06:49 AM

Quote:

Originally Posted by jmurphy

We covered this: QT is QuickTime.
What you are trying to say is: Qt

Stop poisoning the search engines.

Can you please find all the threads that use caliber and ask the mistake makers to fix it?

03-24-2025, 05:59 AM	#1
Aminy Junior Member Posts: 4 Karma: 10 Join Date: Mar 2025 Device: calibre	Screen Blinking/Flicker Issue On Focus Loss Hi, when using the full screen viewer and alt tabbing to my second monitor the calibre program flickers black for less than half a second before going back to normal. This issue happens whether I click onto calibre or click out of calibre/alt tab into or out of calibre while in full screen. While not in full screen the program doesn't have this screen blinking issue. Steps I've taken to solve this problem: Look in settings to see if this is an optional setting. Updating Calibre, I went from version 7 something to current version 8.0.1 Updating Nvidia drivers, from version 572.70 to latest. Tried to reproduce the issue in other applications, but this problem seems to be only in calibre. Other programs do not cause this issue when alt tabbing. More info: I have an extremely old version of Calibre 3.16 that doesn't have this same problem. I tried to screen capture this issue, but this blinking doesn't show up on the screen recording through OBS.

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03-24-2025, 06:45 AM	#2
kovidgoyal creator of calibre Posts: 45,360 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	That's an interaction between your GPU drivers an Qt webengine which is what the viewer uses. You can try disabling hardware rendering it might help, as described here: https://doc.qt.io/qt-6/qtwebengine-debugging.html

03-24-2025, 08:19 AM	#3
Aminy Junior Member Posts: 4 Karma: 10 Join Date: Mar 2025 Device: calibre	Thank you for the quick reply. I spent a long time trying to learn how to disable hardware rendering, I found this old thread https://www.mobileread.com/forums/sh...d.php?t=327243 that gave some more direction. I'm not very tech savvy, so I don't know how to use cmd or add in element variables. I followed the "how to setup environment variables" through one of the links, is this what the environment variable suppose to look like? edit: image doesn't load for me so here is the link https://i.imgur.com/QhoLLIx.png

03-24-2025, 08:35 AM	#4
Aminy Junior Member Posts: 4 Karma: 10 Join Date: Mar 2025 Device: calibre	I think my reply message got deleted somehow, but I'll post again just in case. Sorry, if it's spam. I tried applying the environment variable to disable gpu hardware acceleration and the problem is still persisting. ( I did restart my computer after applying environment varible) More info: g-sync is turned off on nvidia options, Hardware-accelerated GPU scheduling in windows display settings is turned off. Thank you again for the quick reply.

03-24-2025, 09:24 AM	#5
kovidgoyal creator of calibre Posts: 45,360 Karma: 27182818 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Then I'm out ideas, sorry.

03-25-2025, 12:37 PM	#7
jmurphy Zealot Posts: 110 Karma: 1133068 Join Date: Sep 2007 Device: ipaq	[QUOTE=JSWolf;4500144]Get rid of the path for your QT environment variable and add in the quotes. We covered this: QT is QuickTime. What you are trying to say is: Qt Stop poisoning the search engines.

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