Issue viewing/importing a large azw3 file?

[SISTAMINF]

Should I have issues opening a ~300MB .azw on a modern system?


Background

Modern Windows 10 system (Ryzen 9 5900HS, 32GB ram) Calibre 6.9, Dedrm 10.0.3

I bought a new Kindle book from Amazon today, and used the "Download and Transfer Via USB" option for my Kindle, same Kindle used for dozens of titles.

Turns out it's pretty large, 300MB, the largest azw book I have.

I added the file to my Calibre and it added as expected. It correctly displays the title as well as the cover thumbnail in the calibre title screen.

However, the file just hangs with "Preparing book for first read, please wait". Have let it run for ~30 minutes with no change. Process seems to be using roughly a 1 core constantly.

Tried importing more smaller AZW books, just downloaded in the same way and had no issues. Have no problem with 200MB-600MB EPUB. Tried to convert the file to EPUB and I saw it hang as well.

I'm unsure if there's something about a large AZW book, or something about this specific AZW book causing my issues.

Attached a debug log, but I don't see any errors captured.

Please let me know what direction to look in.

[kovidgoyal]

Convert it to EPUB and view that.

[SISTAMINF]

Originally Posted by kovidgoyal

Convert it to EPUB and view that.

I managed to get it to open and display, slowly as an AZW after about an hour. The file displays, but there's a pretty significant lag looking at pages, usable but sticky.

I've now been running a conversion to EPUB for 7 hours and it's been stuck at 47% for most of that time. Seems to be constantly using one core. I've seen RAM usage at around 3GB all the way up to 22GB.

Title is Timelines of History: The Ultimate Visual Guide to the Events That Shaped the World" 2018 edition by DK.

[jhowell]

I took a look at the free sample for that book. It is published in fixed-layout KF8 format, which is not supported by calibre. (Each page has a background image of the complete page along with each word of text individually positioned on it as hidden content. I assume that was done in order to retain the original layout while also allowing dictionary lookup.)

[ownedbycats]

Originally Posted by jhowell

I took a look at the free sample for that book. It is published in fixed-layout KF8 format, which is not supported by calibre. (Each page has a background image of the complete page along with each word of text individually positioned on it as hidden content. I assume that was done in order to retain the original layout while also allowing dictionary lookup.)

It might be worth trying the KindleUnpack plugin. I'm not sure about KF8 in particular, but some fixed-layout files are just a PDF inside Amazon's proprietary wrapper.

[jhowell]

Originally Posted by ownedbycats

It might be worth trying the KindleUnpack plugin. I'm not sure about KF8 in particular, but some fixed-layout files are just a PDF inside Amazon's proprietary wrapper.

This one is definitely not a wrapped PDF as is used for most print replica books. It appears to have been published using a fixed-layout EPUB as the source.

[ownedbycats]

Can Kindle Unpack pull out an EPUB3? Calibre's reader doesn't like fixed-layouts, but theres other viewers (I use AZARDI).

[jhowell]

Originally Posted by ownedbycats

Can Kindle Unpack pull out an EPUB3? Calibre's reader doesn't like fixed-layouts, but theres other viewers (I use AZARDI).

Yes, KindleUnpack should be able to quickly produce an EPUB that can be read using software that supports fixed-layout.