Opening Epub book takes 30s on external display

Ugur · 03-28-2023, 08:38 AM

I'm currently using Calibre on a MacBook Pro 2018 with an i5 processor, 16GB of RAM, and 1TB of storage. However, every time I open an Epub book, it takes about 20-30 seconds to fully load.

Apparently my external monitor (plugged via USB-C) was responsible for the slow down. Unplugging the external monitor (DELL S2722QC) will decrease startup time to 3 seconds!

Plugging in the external monitor and decreasing the resolution of it will decrease the load time to 7 seconds (down from 30s). Still not as fast as on my Macbook screen (3 seconds).

I am guessing that the viewer reads the resolution of the screen and calculates the page size for every page to be opened?

Anyone can point me to a solution?

Thank you very much!

kovidgoyal · 03-28-2023, 10:52 AM

That will be some issue between chromium (which is what the viewer uses to render HTML) and the GPU drivers on your system. You can try turning off hardware acceleration which might help as described here: https://doc.qt.io/qt-6/qtwebengine-debugging.html

Ugur · 03-28-2023, 12:16 PM

Quote:

Originally Posted by kovidgoyal

You can try turning off hardware acceleration ... as described here: https://doc.qt.io/qt-6/qtwebengine-debugging.html

There it says `--disable-gpu`. Do I pass this to `calibre` from the command line?

theducks · 03-28-2023, 01:18 PM

Quote:

Originally Posted by Ugur

There it says `--disable-gpu`. Do I pass this to `calibre` from the command line?

Yes. Or the Target in the shortcuts that launches Calibre or Viewer (any shortcuts the commanded line is used )

kovidgoyal · 03-28-2023, 09:53 PM

Quote:

Originally Posted by Ugur

There it says `--disable-gpu`. Do I pass this to `calibre` from the command line?

No you set it in the environment variable described on that page.

Ugur · 03-29-2023, 02:21 AM

Thank you very much Kovid,

with the new new environment variables file my problem is fixed!

Here's my new environment variables file:

CALIBRE_TEMP_DIR=~/.calibre/temp
CALIBRE_CACHE_DIRECTORY=~/.calibre/cache
QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"

theducks · 03-29-2023, 02:24 AM

Quote:

Originally Posted by kovidgoyal

No you set it in the environment variable described on that page.

Ugur · 03-30-2023, 05:41 AM

The solution worked only a day or so. The problem is back. Several restarts did not help.

03-28-2023, 08:38 AM	#1
Ugur Member Posts: 13 Karma: 10 Join Date: Apr 2020 Device: Kindle	Opening Epub book takes 30s on external display I'm currently using Calibre on a MacBook Pro 2018 with an i5 processor, 16GB of RAM, and 1TB of storage. However, every time I open an Epub book, it takes about 20-30 seconds to fully load. Apparently my external monitor (plugged via USB-C) was responsible for the slow down. Unplugging the external monitor (DELL S2722QC) will decrease startup time to 3 seconds! Plugging in the external monitor and decreasing the resolution of it will decrease the load time to 7 seconds (down from 30s). Still not as fast as on my Macbook screen (3 seconds). I am guessing that the viewer reads the resolution of the screen and calculates the page size for every page to be opened? Anyone can point me to a solution? Thank you very much!

03-29-2023, 02:21 AM	#6
Ugur Member Posts: 13 Karma: 10 Join Date: Apr 2020 Device: Kindle	Solved! Thank you very much Kovid, with the new new environment variables file my problem is fixed! Here's my new environment variables file: CALIBRE_TEMP_DIR=~/.calibre/temp CALIBRE_CACHE_DIRECTORY=~/.calibre/cache QTWEBENGINE_CHROMIUM_FLAGS="--disable-gpu"

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03-28-2023, 10:52 AM	#2
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	That will be some issue between chromium (which is what the viewer uses to render HTML) and the GPU drivers on your system. You can try turning off hardware acceleration which might help as described here: https://doc.qt.io/qt-6/qtwebengine-debugging.html

03-30-2023, 05:41 AM	#8
Ugur Member Posts: 13 Karma: 10 Join Date: Apr 2020 Device: Kindle	The solution worked only a day or so. The problem is back. Several restarts did not help.

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