MobileRead Forums - View Single Post - Viewer Occasionally Takes a Long Time to Open EPUB

enuddleyarbl · 08-25-2022, 08:30 PM

Occasionally, upon first opening an epub in Calibre's viewer, it takes a long time to open (several minutes as opposed to a couple of seconds). Usually, this is just after I've used Calibre's editor to strip out all the publishers' CSS and replace it with my standard set. Once the viewer opens, there's no problem and the delay doesn't repeat itself when I view the book again (even if I have the editor strip out the viewer's files). This doesn't happen with the vast majority of my books. There's nothing special about the books where it happens: the number of chapters (files) is normal (say about 25) and the chapter (file) size is nothing special. AFAICS, there's nothing left in the HTML (or in my standard CSS) that could be causing this kind of slowdown.

This is on Windows 11 Pro x64 (fully updated) with the latest Calibre (6.3). Nothing else is running. Here's a screenshot of Windows Task Manager for the Calibre tasks while it's happening (it's at the top of the list so is what's taking the most resources (even though it's practically nothing).

Sorry I can't figure out how to reproduce it reliably. But, I thought I'd report it in case others run across it. Maybe it's a QT thing?

EDIT: I've tried getting this image down to the forum's recommended size, but it becomes unreadable. it's a pretty small image, so maybe it's ok. If not, let me know and I'll put the teeny-tiny one in.

Moderator Notice
Changed to attachment. Paperclip on Advanced Menu

EDIT 2: When I checked the task manager, I didn't even see Windows Defender churning away. So, I don't think the antivirus is the issue (if it were, I'd have thought it would be at the top of the task list). But, next time it happens, I'll take a look for what Defender is doing in particular.

08-25-2022, 08:30 PM	#1
enuddleyarbl Guru Posts: 784 Karma: 1538394 Join Date: Sep 2013 Device: Kobo Sage	Viewer Occasionally Takes a Long Time to Open EPUB Occasionally, upon first opening an epub in Calibre's viewer, it takes a long time to open (several minutes as opposed to a couple of seconds). Usually, this is just after I've used Calibre's editor to strip out all the publishers' CSS and replace it with my standard set. Once the viewer opens, there's no problem and the delay doesn't repeat itself when I view the book again (even if I have the editor strip out the viewer's files). This doesn't happen with the vast majority of my books. There's nothing special about the books where it happens: the number of chapters (files) is normal (say about 25) and the chapter (file) size is nothing special. AFAICS, there's nothing left in the HTML (or in my standard CSS) that could be causing this kind of slowdown. This is on Windows 11 Pro x64 (fully updated) with the latest Calibre (6.3). Nothing else is running. Here's a screenshot of Windows Task Manager for the Calibre tasks while it's happening (it's at the top of the list so is what's taking the most resources (even though it's practically nothing). Sorry I can't figure out how to reproduce it reliably. But, I thought I'd report it in case others run across it. Maybe it's a QT thing? EDIT: I've tried getting this image down to the forum's recommended size, but it becomes unreadable. it's a pretty small image, so maybe it's ok. If not, let me know and I'll put the teeny-tiny one in. Moderator Notice Changed to attachment. Paperclip on Advanced Menu EDIT 2: When I checked the task manager, I didn't even see Windows Defender churning away. So, I don't think the antivirus is the issue (if it were, I'd have thought it would be at the top of the task list). But, next time it happens, I'll take a look for what Defender is doing in particular. Attached Thumbnails Last edited by theducks; 08-25-2022 at 09:46 PM.