MobileRead Forums - View Single Post - Abysmal performance with a particular file

eschwartz · 06-29-2016, 10:17 AM

calibre does not actually have a MOBI reading algorithm.
The Viewer only supports EPUB, and all other formats are converted on the fly to EPUB for viewing (well, technically I believe just the first step of a conversion, which is unpacking it and transforming it into an OEB model).

It is for this reason that EPUB is the preferred Viewer format -- no need to pre-convert the book. And books which are very slow are recommended to be converted to EPUB to speed up future viewing.

And dictionaries contain a lot of complex internal markup, which makes the conversion have to work a lot harder.
And dictionaries aren't supported in calibre anyway, so all that markup gets dropped. If you leave it for long enough (and complex conversions, which any dictionary certainly qualifies as, have been known to take up to 48 hours to finish) it will result in an EPUB that reads like an ordinary book, no special dictionary formatting at all so no semantically defined entries.

06-29-2016, 10:17 AM	#2
eschwartz Ex-Helpdesk Junkie Posts: 19,421 Karma: 85400180 Join Date: Nov 2012 Location: The Beaten Path, USA, Roundworld, This Side of Infinity Device: Kindle Touch fw5.3.7 (Wifi only)	calibre does not actually have a MOBI reading algorithm. The Viewer only supports EPUB, and all other formats are converted on the fly to EPUB for viewing (well, technically I believe just the first step of a conversion, which is unpacking it and transforming it into an OEB model). It is for this reason that EPUB is the preferred Viewer format -- no need to pre-convert the book. And books which are very slow are recommended to be converted to EPUB to speed up future viewing. And dictionaries contain a lot of complex internal markup, which makes the conversion have to work a lot harder. And dictionaries aren't supported in calibre anyway, so all that markup gets dropped. If you leave it for long enough (and complex conversions, which any dictionary certainly qualifies as, have been known to take up to 48 hours to finish) it will result in an EPUB that reads like an ordinary book, no special dictionary formatting at all so no semantically defined entries. Last edited by eschwartz; 06-29-2016 at 10:20 AM.