converting to "same" format - any side effects?

[cybmole]

as I currently understand things there are a couple of reasons for needing to convert to same format e.g. to run mobi to mobi or epub to epub.

one is to force the inclusion of metadata which was edited or downloaded after book was added to library.

the other is to force the application of header/footer rules or any other custom rules

so to check my understand lets say I've added a book in both formats and now want to force both of the above events -

1. is convert to same format the "proper" way to do it, or is one format intrinsically "better" and thus should be used as source both times ? does converting to "same" format apply the header / footer rules ?

2. will anything be downgraded - as I understand things the conversion will go e.g. out of mobi to an intermediate format, than back into mobi -so is anything lost in that process ? ( my mental analogy is with video formats - where this would be a bad thing )

[FizzyWater]

I like to add the metadata as a cover page, and set a fixed font size for my epubs. I haven't noticed any degradation in my epub-to-epub conversions. However, I make sure to keep a copy of my original epubs, just in case.

[DoctorOhh]

Originally Posted by cybmole

as I currently understand things there are a couple of reasons for needing to convert to same format e.g. to run mobi to mobi or epub to epub.

one is to force the inclusion of metadata which was edited or downloaded after book was added to library.

Using the features of Send to Device, Save to Disk, or Connect to folder will insert metadata. No need for a conversion for inserting metadata.

Originally Posted by cybmole

the other is to force the application of header/footer rules or any other custom rules

Most folks that use these rules apply them during the initial conversion from Mobi to ePub or vice-a-versa. But yes converting epub to epub you can use this rule.

Myself, if I already have the books as a epub with acceptable formatting, then I will open it in Sigil to handle headers/footers.

Originally Posted by cybmole

2. will anything be downgraded - as I understand things the conversion will go e.g. out of mobi to an intermediate format, than back into mobi -so is anything lost in that process ? ( my mental analogy is with video formats - where this would be a bad thing )

There are certain options that can drastically alter your book during conversion. If you want to minimize any changes then on the Preferences - Common Options - Look & Feel page check Disable font size rescaling and leave everything else unchecked. On the Structure detection page leave Preprocess input file to possibly improve structure detection unchecked.

As FizzyWater stated if it matters that much keep a backup because a epub - epub conversion will overwrite the existing epub book in the library.

That said, I always do font size rescaling and both remove spaces between paragraphs/add indent and insert spaces between paragraphs. Experiment to see what you're comfortable with.

[cybmole]

well, learning this stuff 1st hand could be a very slow experience, I'd really have to read each book twice - before & after forced conversion - to see what differences if any were occuring. I was hoping that someone who understood the conversion code could enlighten me as to what it actually does. I'm mostly interested in what goes on within just 4 permutations: from epub/mobi to epub/mobi- so e to e, e to m, m to e, m to m

e.g.for all I know tha preprocess & header/footer options may not even be applicable to certain types of conversions, and it may be that , for example , going epub to rtf to epub causes no degredation but how would I know, except for having a photographic memory & reading the book twice ???

I do understand the concept of font rescaling, but "preprocess" is a vague option which is OFF by default.
I am keeping backups of all sources, until I understand calibre options better.

[ldolse]

None of the conversion or conversion options would require you to read the book twice. All the data would be there, but there may be some minor formatting changes, primarily around spacing and margins.

What the preprocess option does depends on the book, for a well formatted book it basically doesn't do anything. For a poorly formatted book it will do a variety of things, but none of those things should actually delete any text data. That option doesn't apply to any conversions using epub as a source btw.

[cybmole]

Originally Posted by ldolse

...preprocess option ....That option doesn't apply to any conversions using epub as a source btw.

that's the sort of info I was hoping for, thanks - I thought it likely that not all options apply to all formats but there noes not seem to be any detailed documentation.

I still find it strange that there is no "update metadata" option & that a full conversion ( i.e. all content going into & out of an intermediate HTML ? ) is needed just to update metadata within a format.
To make an analogy with music formats that I work with a lot; I can change any MP3 metatdata via a tag editor, I don't have to unencode & reencode the MP3 audio data in order to add cover art, lyrics etc to the mp3 container.

PS do the concepts of "header" & "footer" even apply for e-readers which use mobi & epub ?

you would not normally want headers & footers on an e-reader screen , & if they were to appear, the device firmware would surely have to manage their placement . I can change font size within KIndle after sending the mobi files to it, thus Kindle itself is handling pagination on-the-fly ?

[cybmole]

Originally Posted by dwanthny

Using the features of Send to Device, Save to Disk, or Connect to folder will insert metadata. No need for a conversion for inserting metadata.

.

well ok - but "send to disc" can't be used on the library folder - it's only for sending the book somewhere else. why can't there be an option to apply current metadata to current library copies ( preferably in batch mode) ?

then I can inspect how the book will apear on my device ( via internal reader) before sending it

with current release of Calibre I'd have to

select all books,
send them to disc ( somewhere) in all formats,
then delete library,
create new library,
add them all back to library

in order to achieve what I want - seems very roundabout / non-intuitive ?

[ldolse]

As Dwanthy noted, the save to disk and a few other options update the metadata without a full conversion. Use one of those options and then import the updated file back to Calibre. I haven't tried this, so YMMV. You could use the batch mode to send a bunch of files somewhere else, then re-import them.

There isn't really any such thing as 'header' or 'footer' for any formats. Those are simply placeholders for find/replace patterns which are most commonly used to remove headers/footers. Generally either one can be used to remove both the header and the footer. To make any use of them you would need to learn how to use regular expressions though. If enabled they do apply to all formats though.

You're correct that the device would need to manage the placement of headers and footers. The epub specification doesn't fully define header/footer handling, so there are no devices which attempt to do that. The header/footer removal feature is for removing headers/footers from other documents such as pdf.

[ldolse]

I just don't worry about the fact that the files haven't been updated within the library. As soon as I send them to my reader they're correct.

Likewise if I wanted to share with a friend they would also be correct when I use the 'save to disk' option.

If you just work off the assumption you'll never access your files directly without asking Calibre to place a copy somewhere else it all works out ok.

[HarryT]

Originally Posted by cybmole

well ok - but "send to disc" can't be used on the library folder - it's only for sending the book somewhere else. why can't there be an option to apply current metadata to current library copies ( preferably in batch mode) ?

The Calibre library is a "black box" - you should neither know nor care what's in there.

The only relevant point is that if you edit the metadata and then send the book to your device, either directly from Calibre, or via a "Save to Disk", then it will have the metadata that you've set.

[cybmole]

Originally Posted by ldolse

...The header/footer removal feature is for removing headers/footers from other documents such as pdf.

thanks again, so If I abstain from using any PDF sources, can I just forget all about header & footer removal, & preprocessing & not have to learn regex at all ?

I think that would work for me, & I guess I can always use send to device to load up my Kindle.

If I use that route, but then use Kindle to delete finished books, I'm left with empty subfolders on Kindle but I guess it's safe to delete those via windows.

I'm reluctant to move, copy, delete stuff on the Kindle drive as it appears in winodws, as I don't know how Kindle firmware keeps track of stuff. again, the frustration here is lack of doceumentation , I know at lot about PC software & Windows but next to nothing about Kindle firmware.

my son's sony PRS350 has not arrived yet but I think it comes with some annoying sony software that I was hoping to completly bypass. I had planned to just plug it in & copy files to it, as a USB drive, but maybe I should do that thorugh calibre. It's a brand new device though so I don't know if any calibre users have been able to test the calibre interface with prs-350 yet ?

[HarryT]

Originally Posted by cybmole

thanks again, so If I abstain from using any PDF sources, can I just forget all about header & footer removal, & preprocessing & not have to learn regex at all ?

Pretty much, yes.

If I use that route, but then use Kindle to delete finished books, I'm left with empty subfolders on Kindle but I guess it's safe to delete those via windows.

I'm a little surprised that you're seeing subfolders. What circumstances are you seeing them in?

I'm reluctant to move, copy, delete stuff on the Kindle drive as it appears in winodws, as I don't know how Kindle firmware keeps track of stuff.

You can freely copy and delete things from the "documents" folder - that's where all your books go. Don't touch anything else. The key thing to remember is to never, NEVER, unplug the USB cable without doing a "Safely Remove Hardware" in Windows first.

[ldolse]

Originally Posted by HarryT

Pretty much, yes.

Well, pretty much yes as long as your source didn't come from lazy pirates who converted to epub/mobi/lrf from pdf and didn't bother to remove the footers at that stage, which is what you saw with the ABC thing.

[cybmole]

Originally Posted by HarryT

Pretty much, yes.



I'm a little surprised that you're seeing subfolders. What circumstances are you seeing them in?



You can freely copy and delete things from the "documents" folder - that's where all your books go. Don't touch anything else. The key thing to remember is to never, NEVER, unplug the USB cable without doing a "Safely Remove Hardware" in Windows first.

when calibre adds a book to Kindle 3 it does not place it directly into the documents folder on kindle, it places it in an author subfolder ( i think) within Kindle's documents folder.I'm 99% certain of that but if you think different I will connect the Kindle & run more tests.
If I email a book to my kindle, then it's placed directly in the kindle documents folder, but then the the author is replaced with my e-mail address, which is naff.
if I do it manually with calibre not running then I plug in the kindle, open up my calibre library or source folder & just drag n drop to Kindls docs.

so if , lets say, Calibre put a book in a subfolder, then I moved it at a later date, or renamed that subfolder via windows, then that could confuse the Kindle which had already noted the old location ?
I heed what you say about "safely remove hardware" but I wonder how serious that really is - people in my family plug phones, cameras, USB drives etc in & out of PCs all the time & they never bother with that!
windows, by default, does not cache writes to removable media.

[cybmole]

Originally Posted by ldolse

Well, pretty much yes as long as your source didn't come from lazy pirates who converted to epub/mobi/lrf from pdf and didn't bother to remove the footers at that stage, which is what you saw with the ABC thing.

i expect that in time, I will learn how to de-drm my own paid-for sources, like I did with music & DVDs.

but right now that looks horribly geeky, so I await simple-to-use ultilities that don't require python expertise or similar.

I'm not going to to buy family books twice, just because Sony & Amazon use different formats!

plus hopefully the sony "borrow ebooks from your local library" scheme will arrive here. It is already up & running in Croydon where we used to live.