Identify converted books (files/formats)?

[StillReading]

I wonder if there is a way to identify which books (files or formats, to be more precise) have been converted by Calibre, and which are the "original" formats.

My thinking: from what I understand, conversion is an inherently "lossy" process, as there is no guarantee the conversion will produce an identical copy of the original book in the new format (identical in this case meaning "looking exactly like the original format in all details"). I'm currently not using "manual conversion", I'm thinking about the auto-convert process when copying books to my eBook reader (Kindle Paperwhite). Any insight is appreciated.

[theducks]

Manually at add time using a custom column (#Master_Format)

EPUB is a good 'Master' to start with (I believe there is a Preferred format list somewhere in the FAQ)

The Quality check PI can do some checks, but so many things can leave a Calibre fingerprint on the book (including the publisher)

Your OS might help YOU see it (but not get the info into Calibre without a bit of programming on your part)

WXP CLI example (help DIR to see other CLI switches)

T:\Users\Shared>dir /s/tc IntakeLib

[StillReading]

Thanks for the info! Didn't think about "creation date", though it's of no use to me right now because I've copied my entire library after Calibre created quite a lot of converted formats (beginner's "mistake"). I can still try to identify those manually, though.

A custom column wouldn't help I think. Metadata is assigned to a book, not a single format, isn't it? If there is a way to assign metadata to a format instead of a book I didn't find it yet, and I've looked everywhere (Google, forum search, Calibre manual, etc.).

[theducks]

Originally Posted by StillReading

Thanks for the info! Didn't think about "creation date", though it's of no use to me right now because I've copied my entire library after Calibre created quite a lot of converted formats (beginner's "mistake"). I can still try to identify those manually, though.

A custom column wouldn't help I think. Metadata is assigned to a book, not a single format, isn't it? If there is a way to assign metadata to a format instead of a book I didn't find it yet, and I've looked everywhere (Google, forum search, Calibre manual, etc.).

My column contains the Imported (original)formats name: EPUB or Mobi or PRC...
for that title

[StillReading]

I see, I think I understand how I could implement this for my collection.

I've just realized though: the information about the "master format" seems to already be in the Calibre database! I've just tried this: a book imported in EPUB format, converted to MOBI by Calibre in order to upload it to my Kindle. When I select "Preview" in Calibre, Calibre opens the EPUB version of the book (visible because Calibre will update its reading position, thus the file date of the EPUB is changed). This is only a simple test of course, and my conclusion could be wrong. To phrase a question: how does Calibre determine which format to open for a "Preview" when a book has multiple formats?

I'm wondering: am I the only one slightly confused by how Calibre handles (auto-) conversions for a single book? I think I have an idea how this important functionality could be made more transparent to the user, though I'd like to have some more feedback from other users. Could be I'm the only one with this "issue", after all (; .

[PeterT]

The calibre viewer is strictly an ePub viewer. ALL other supported formats are sent through a basic conversion to be viewed by it.

[eschwartz]

You can do a search for

identifiers:"=mobi-asin:"

The mobi-asin identifier is created by calibre when it imports an AZW3/MOBI (this only happens during the Add books process, using the first Add option*) with a non-null exth 113 field (the asin identifier). It is not saved as asin because asin creates a link to the product page on amazon.com, but the exth 113 field may be for a book from the UK or other foreign storefronts.

This is important because metadata fetching will download asin metadata but it will never import calibre's custom mobi-asin field.


tl;dr
If a book has a mobi-asin identifier, it is pretty much guaranteed that it came from Amazon, and certainly implies that the original format was either MOBI or AZW3.


* -- The second Add option is traditionally used when adding from another library folder, it imports the metadata from the metadata.opf which overrides fetching metadata from inside the book file itself.