OPDS - iPad. Files downloaded to Stanza or Mega Reader do not keep metadata

COLEY54321 · 04-14-2012, 06:47 PM

Hi all Calibre fans,

Having just bought an iPad, I read up on the best way to organise my pdfs and occasional epubs, and I was advised to use Calibre and the OPDS content sever so I could access my library when not at home.

I have spent a long time correctly renaming and tagging all my books within Calibre. When I search the OPDS through an app such as Stanza or Megareader, the titles and authors are all listed correctly. However, when I download a pdf I want to read, it downloads with the original Title / author, not the corrected one I have written in Calibre. In a hypothetical example, the book might originally be called "12345.pdf". This was drag and dropped into Calibre and the title correctly changed to "Jane Eyre". When downloaded to Stanza it shows as "12345.pdf" in the library books.

From doing a bit of research my understanding is that because of design limitations of Calibre, it does not / cannot write the corrected metadata to the file (unless you save to disk or send to device).

Are there any plans to correct what seems like a design limitation? Is there a way I can get this to work in Stanza or any other OPDS capable app, otherwise this whole process has been a big waste of time for me; as I now have this lovely Calibre database, but incorrect Titles when using OPDS (which was the main reason I was attracted me to using Calibre in the first place).

A work around might be to 'Save to disk' and create a new database? But not sure how to do this or how successful it would be, and seems a rather convoluted way of achieving a rather basic aim; i.e. data I write to the database should also be written to the files in all instances where possible?? Any help on this would be appreciated.

I do appreciate there must be a designed reason for not allowing this and if it were 'that simple' you would have already done it, but it does seem like a rather big negative / let down to an otherwise amazing program.

kovidgoyal · 04-14-2012, 11:17 PM

It's not going to happen. PDF is a really awful format.

1) It support a very limited subset of metadata
2) To update metadata the entire PDF has to be read into memory and re-written, which is very slow
3) There exists no library that does not either a) crash b) freeze when updating metadata in some PDFs.

COLEY54321 · 04-15-2012, 04:29 AM

Thank you for your reply.

To confirm, does that mean it should be working for epubs? i.e. epubs get their metadata updated and written to file, and will be corredt when downloaded to Stanza?

Is there any kind of work around? i.e. can I not select formats:"=PDF" and then save to single directory on disk. Then from that directory drag back into Calibre (and via some setting merge duplicates and keep newer file?).

Thanks for your help.

p.s. I only just realised you're the guy that makes Calibre - great program!

kovidgoyal · 04-15-2012, 04:53 AM

EPUB and MOBI both have their metadata updated when transmitted via the content server. Whether Stanza picks up the metadata, I have no idea.

COLEY54321 · 04-15-2012, 05:03 AM

Ok. So, do you think that work around could work?

kovidgoyal · 04-15-2012, 05:14 AM

Try it and see.

COLEY54321 · 04-15-2012, 03:21 PM

Hi. Yes it worked!

ALL EPUB formats worked perfectly (and so I don’t understand why data isn’t written to file instantaneously for this format).

PDF – I agree seems dodgy. Metadata didn't get written to some files (e.g. title, author, and tags didn't get updated in file metadata). But that was only for 5 books out of 620 I did.

The ones that didn't work I did a binary duplicate search on > Deleted the duplicates > opened containing folder of the original > opened with Adobe Acrobat (or you could use any other PDF writer such as Coral PDF Fusion) adjusted one of the property fields and saved the file > Went back into calibre and repeated the process of saving to disk and dragging back in for that file, and it worked.

It's almost as if some PDFs are locked up and need freeing up by forcing update of the fields within the file.

But all in all, job well done.

Braveheart · 04-18-2012, 09:49 AM

Quote:

Originally Posted by COLEY54321

Hi. Yes it worked!

ALL EPUB formats worked perfectly (and so I don’t understand why data isn’t written to file instantaneously for this format).

PDF – I agree seems dodgy. Metadata didn't get written to some files (e.g. title, author, and tags didn't get updated in file metadata). But that was only for 5 books out of 620 I did.

The ones that didn't work I did a binary duplicate search on > Deleted the duplicates > opened containing folder of the original > opened with Adobe Acrobat (or you could use any other PDF writer such as Coral PDF Fusion) adjusted one of the property fields and saved the file > Went back into calibre and repeated the process of saving to disk and dragging back in for that file, and it worked.

It's almost as if some PDFs are locked up and need freeing up by forcing update of the fields within the file.

But all in all, job well done.

Would you mind explaining in simple terms what the workaround was that you used for pdfs - as I have come across the same problem....(sorry couldn't quite follow in the original thread - my brain is a bit zonked from searching for a solution to this one!).

Many thanks,
John

04-14-2012, 06:47 PM	#1
COLEY54321 Junior Member Posts: 4 Karma: 10 Join Date: Apr 2012 Device: iPad 3	OPDS - iPad. Files downloaded to Stanza or Mega Reader do not keep metadata Hi all Calibre fans, Having just bought an iPad, I read up on the best way to organise my pdfs and occasional epubs, and I was advised to use Calibre and the OPDS content sever so I could access my library when not at home. I have spent a long time correctly renaming and tagging all my books within Calibre. When I search the OPDS through an app such as Stanza or Megareader, the titles and authors are all listed correctly. However, when I download a pdf I want to read, it downloads with the original Title / author, not the corrected one I have written in Calibre. In a hypothetical example, the book might originally be called "12345.pdf". This was drag and dropped into Calibre and the title correctly changed to "Jane Eyre". When downloaded to Stanza it shows as "12345.pdf" in the library books. From doing a bit of research my understanding is that because of design limitations of Calibre, it does not / cannot write the corrected metadata to the file (unless you save to disk or send to device). Are there any plans to correct what seems like a design limitation? Is there a way I can get this to work in Stanza or any other OPDS capable app, otherwise this whole process has been a big waste of time for me; as I now have this lovely Calibre database, but incorrect Titles when using OPDS (which was the main reason I was attracted me to using Calibre in the first place). A work around might be to 'Save to disk' and create a new database? But not sure how to do this or how successful it would be, and seems a rather convoluted way of achieving a rather basic aim; i.e. data I write to the database should also be written to the files in all instances where possible?? Any help on this would be appreciated. I do appreciate there must be a designed reason for not allowing this and if it were 'that simple' you would have already done it, but it does seem like a rather big negative / let down to an otherwise amazing program.

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04-14-2012, 11:17 PM	#2
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	It's not going to happen. PDF is a really awful format. 1) It support a very limited subset of metadata 2) To update metadata the entire PDF has to be read into memory and re-written, which is very slow 3) There exists no library that does not either a) crash b) freeze when updating metadata in some PDFs.

04-15-2012, 04:29 AM	#3
COLEY54321 Junior Member Posts: 4 Karma: 10 Join Date: Apr 2012 Device: iPad 3	Thank you for your reply. To confirm, does that mean it should be working for epubs? i.e. epubs get their metadata updated and written to file, and will be corredt when downloaded to Stanza? Is there any kind of work around? i.e. can I not select formats:"=PDF" and then save to single directory on disk. Then from that directory drag back into Calibre (and via some setting merge duplicates and keep newer file?). Thanks for your help. p.s. I only just realised you're the guy that makes Calibre - great program!

04-15-2012, 04:53 AM	#4
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	EPUB and MOBI both have their metadata updated when transmitted via the content server. Whether Stanza picks up the metadata, I have no idea.

04-15-2012, 05:03 AM	#5
COLEY54321 Junior Member Posts: 4 Karma: 10 Join Date: Apr 2012 Device: iPad 3	Ok. So, do you think that work around could work?

04-15-2012, 05:14 AM	#6
kovidgoyal creator of calibre Posts: 43,860 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Try it and see.

04-15-2012, 03:21 PM	#7
COLEY54321 Junior Member Posts: 4 Karma: 10 Join Date: Apr 2012 Device: iPad 3	Hi. Yes it worked! ALL EPUB formats worked perfectly (and so I don’t understand why data isn’t written to file instantaneously for this format). PDF – I agree seems dodgy. Metadata didn't get written to some files (e.g. title, author, and tags didn't get updated in file metadata). But that was only for 5 books out of 620 I did. The ones that didn't work I did a binary duplicate search on > Deleted the duplicates > opened containing folder of the original > opened with Adobe Acrobat (or you could use any other PDF writer such as Coral PDF Fusion) adjusted one of the property fields and saved the file > Went back into calibre and repeated the process of saving to disk and dragging back in for that file, and it worked. It's almost as if some PDFs are locked up and need freeing up by forcing update of the fields within the file. But all in all, job well done.

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