huge oversize zip-fb2??

rbruce1314 · 02-10-2011, 03:46 AM

Elsewhere I posted about losing images in a epub-fb2. Since then I downloaded the zip file (5.7M) and converted it to fb2. The images stayed but the fb2 file is a massive 35.2 MB in size, for a 120 page book with illustrations on most pages. (By comparison the epub file was 6.7M)

This compares with a 300 page book with full photographs on every other of its pages and a file size of just 7.9M.

Has something gone wrong in the conversion (the result looks fine) to make it this big???

DoctorOhh · 02-10-2011, 06:21 AM

Quote:

Originally Posted by rbruce1314

This compares with a 300 page book with full photographs on every other of its pages and a file size of just 7.9M.

Has something gone wrong in the conversion (the result looks fine) to make it this big???

Did the conversion either resize the images larger or increase their dots per inch DPI? Either of these would increase the size of each image file.

rbruce1314 · 02-10-2011, 06:29 AM

Good question! I've since used a mobi file as the base for the fb2 conversion and from a mobi of 8.1M I've ended up with an fb2 of 14.2M with sensible (at 640x360) size images.

I did note the the images in the zip/HTML file were .png rather than .jpeg: does this make a difference??

user_none · 02-10-2011, 09:05 AM

MOBI and EPUB are both compressed fomats. FB2 is not. FB2 also has to have binary data (images) base64 encoded which increases their size by about 33%.

BobC · 02-10-2011, 04:40 PM

Quote:

Originally Posted by user_none

MOBI and EPUB are both compressed fomats. FB2 is not. FB2 also has to have binary data (images) base64 encoded which increases their size by about 33%.

But if you are using a reader such as the Hanlin with Coolreader as its FB2 reader you can Zip up the FB2 then rename the ZIP as <whatever>.fb2.zip and the reader will decompress and open it on-the-fly.

Mind you it might choke on one that large.

BobC

02-10-2011, 03:46 AM	#1
rbruce1314 Groupie Posts: 179 Karma: 1021404 Join Date: Apr 2010 Location: Stroud, UK Device: Xgody tablet, LG G3 (Android), moon+reader	huge oversize zip-fb2?? Elsewhere I posted about losing images in a epub-fb2. Since then I downloaded the zip file (5.7M) and converted it to fb2. The images stayed but the fb2 file is a massive *35.2 MB* in size, for a 120 page book with illustrations on most pages. (By comparison the epub file was 6.7M) This compares with a 300 page book with full photographs on every other of its pages and a file size of just 7.9M. Has something gone wrong in the conversion (the result looks fine) to make it this big???

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02-10-2011, 06:29 AM	#3
rbruce1314 Groupie Posts: 179 Karma: 1021404 Join Date: Apr 2010 Location: Stroud, UK Device: Xgody tablet, LG G3 (Android), moon+reader	Good question! I've since used a mobi file as the base for the fb2 conversion and from a mobi of 8.1M I've ended up with an fb2 of 14.2M with sensible (at 640x360) size images. I did note the the images in the zip/HTML file were .png rather than .jpeg: does this make a difference??

02-10-2011, 09:05 AM	#4
user_none Sigil & calibre developer Posts: 2,487 Karma: 1063785 Join Date: Jan 2009 Location: Florida, USA Device: Nook STR	MOBI and EPUB are both compressed fomats. FB2 is not. FB2 also has to have binary data (images) base64 encoded which increases their size by about 33%.

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