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Old 02-13-2013, 10:22 PM   #12
Grand Sorcerer
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Posts: 12,652
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Join Date: Jul 2011
Location: Sydney, Australia
Device: Kobo: Touch, Glo, Aura H2O, Glo HD, Aura ONE
Originally Posted by kc7zzv View Post
Could you PLEASE stop belaboring this point. I don't CARE. Either it doesn't follow the spec, in which case I don't care, because it's "close enough" for import to treat as an epub or it does follow the spec, in which case it's (by definition) close enough to treat as an epub for import purposes.
My apologies for pointing out an error in your post and explaining it. But, as it was the first time I referred to this in this thread, I think "Belabouring this point", is a bit much.

Now if you had accused me of being pedantic in my explanation, then I will plead guilty. I was trying to make sure you understood what was going on. The only issue with the "close enough" is that Kobo might decide this is a bug (reading a epub 3 attribute in an epub 2 file) and fix it.

But, to belabour a point before I continue. I think that having calibre capable of putting properly formatted kepubs on the Kobo devices is a good idea. But, I am not convinced that having kepub as a format inside calibre is very useful. And I think don't think it is more useful than the driver method.
> I don't know why you are seeing that performance. I recently took a 30 chapter epub that was built with one chapter per file and combined them down to three files. The sizes where about 350KB, 250KB and 700KB each. This worked perfectly on the device with no noticeable performance from the split version.

Well, I don't either. I assume it has something to do with the size, and I expect to find out during my initial exploration.
Huh? "Well, I don't either" what? A big part of your premise is that size matters. If you don't see a difference in performance, than why are you worrying? But below you have done some testing and see a heavy impact.
> But if the sizes are the problem, you have your conversion options set wrong. You should use the "Structure Detection" page of the conversion options to split the files into chapter based files in the epub. This is what you are saying is needed to be done to create a kepubs, so you will be relying on those options anyway.

> to be clear, a kepub does not have to be split up into a file per chapter. They follow the exact same rules for this as an epub. The designer of the book decides how to do it and Kobo just adds the extra spans and ids. I haven't seen many kepubs that don't split the chapters, but I do have some. And an important thing is that every kepub I have looked at, has exactly the same file structure as the epub I also got from the Kobo shop.

As I see it, this is entirely beside the point. Split size (in my very limited testing) can heavily impact performance, in which case, the split size on kepubs should be optimized for the kobo. It is possible that it doesn't have an impact on performance, in which case I expect to find that out too.

Just give up on convincing me that this won't speed things up. I've read enough information supporting this to believe it. Either it will, and I'll find that out in my exploration, before I write much code, or it won't, and I'll find that out during my exploration, before I write much code.
I am not trying to convince you that splitting a epub or kepub into smaller chunks won't be faster when turning the page. I am fairly sure that it will be. But there is a minimum size that makes it slower as going from one file in the epub/kepub to another is slower.

From what I see for performance and usability, the best split is at chapter marks [pedantic me: where it says "Chapter x" or "Part x" or just "x"]. It is rare to find a book that has chapters large enough to want to split them into smaller files. But, it is common to find epubs that have not been split at chapters.

As you think that size of file is so important, do the tests now. Play with the split settings in the calibre conversion to to set-up file size. Then use Joel's driver to put properly formatted kepubs onto the device. But also put the epub version on to see what the difference is with the device treating the same book as an epub an a kepub (yes the kepub has extra spans in it which makes it not the same, but without the spans, it isn't correctly formatted for the kepub reader). And please tell me the results. I am very interested to know what they are. I'll admit that I expect the size range for well performing epubs and kepubs will be very wide. I know that the first thing I will do after seeing the results is examining my library to see how they fit and what changes I need to make.

> What changes are you talking about? I tweak my epubs, but that is because I prefer them to look like paper books. In fact, if I have a paper version, I use that as the guide. But, I would be stunned if I am doing anything that would make it look worse on other readers. About the only thing I do that I think is specific to the Kobo reader is to push chapter headings low enough on the screen that they aren't hidden by the top menu when it is displayed. If you have have some examples, I would love to hear what they are.

a) Chopping the epub into tiny pieces puts in page-breaks in ugly places. It it doesn't help performance, then this isn't something I want on other readers.
Why one earth would you do that? It is not needed on any of the Kobo devices to split the text into "tiny pieces". Or do we disagree on the how big "tiny" is? And if you read my posts, I am a big advocate of splitting at chapter breaks. That will not put page-breaks in ugly places.
b) Adding the kobo ids, spans, and javascript make the file bigger, and so does splitting the file into more pieces.
Huh? Of course all that is the case. Why would you do any of that if the size is a big concern to you. The spans and ids have nothing to do with other readers (that was the point I was asking about) as they are only added to kepubs. Same with the kepub specific javascript. But I don't understand how this affects other readers as kepubs don't go onto them.
Finally, something you didn't mention is that some people don't want their Kobo reading their epubs in the "kepub reader". (Yes, calling it the kepub reader is a slight oversimplification. Please don't waste our time correcting me) By treating both formats as first class formats, users can easily choose which they want in the same way they choose between other formats, like epub vs lit.
Firstly, I won't correct you because I think "kepub reader" is a perfectly good description. I do use "kepub renderer" in some places, but that is because it fits the discussion.

But, I'm not sure if I understand the first sentence. I do know that a lot of people don't want their epubs read in the kepub reader (I'm one of them). And I do know that a lot of people want to read their epubs in the kepub reader. If you go over to the Kobo forum, you will see I have discussed it there plenty of times. In fact, I started a thread to tell people how to do this (and had someone promptly point to a much earlier thread that I had forgotten about).
Yes. I want to try to split on chapters.
This time I am belabouring a point. Calibre conversion does this already and does it very well. You don't need to do anything to get it. And you don't want to not offer it as an option. Some people don't want this and will want the single file. Even if the performance is not as good.
Basically, I want to make Calibre work really well with the Kobo, out of the box, not just for me after configuring settings, templates, the plugboard, etc...
Sorry, but calibre does work very well with the Kobo device out of the box with no configuration changes. Any changes people make are because they want to fine tune it. The issues you are talking about are related to the structure of the books being read or maybe some firmware bugs.

I'll repeat my ending statement from the last post:

I am being discouraging about this because I don't think it is that useful. And I am also playing Devil's Advocate a bit to make sure you understand what you are planning to do. But, if you decide to do this, I will be happy to help.
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