Can Calibre list pdf encoding info?

[MarjaE]

If I check the individual files in the Mac Finder, command-i can list compatibility level, resolution, security, and encoding software. Maybe Linux or Windows equivalents add color rendering or other info.

Any of these can help show which devices can read which pdfs, which is important.

I pre-process my pdfs for my Kindle, while keeping the originals *and* the pre-processed versions. Sorting by resolution and/or color rendering can help sort out which copies I've processed using which tools and settings.

If other users don't pre-process theirs, they may still find it handy.

Is there a way to set up a column for any of these things?

[compurandom]

You can create any custom column you want in calibre.

Populating that data from the pdf would require either manual entry or a plugin.

[theducks]

A custom column (tag type?) is an answer.
You have been around these forums for years. Plugins get done by folk like you with their unique 'NEEDS'. Unless you write it, don't expect it will be done (yours is a unique use case). There are literally 1000's of ways Calibre users have found to WANT Calibre to Auto do their unique thing.

Even one of the most heavily USED PI is having trouble finding a new 'maintainer' (needed for the up coming Python update)

[compurandom]

I've actually been thinking of writing a better pdf metadata import plugin for quite a while. I looked at it last night and the pdfinfo program that comes with calibre is pretty rudimentary. Pretty much the ONLY metadata it recognizes that isn't already imported is the pdf version.

Personally, I'd like a plugin that could import the toc length from the pdf (although 0, 1, many would be enough info for me). But this would require either replacing pdfinfo or pulling in a larger python pdf manipulation library I think.

[theducks]

Originally Posted by compurandom

I've actually been thinking of writing a better pdf metadata import plugin for quite a while. I looked at it last night and the pdfinfo program that comes with calibre is pretty rudimentary. Pretty much the ONLY metadata it recognizes that isn't already imported is the pdf version.

Personally, I'd like a plugin that could import the toc length from the pdf (although 0, 1, many would be enough info for me). But this would require either replacing pdfinfo or pulling in a larger python pdf manipulation library I think.

There is a FAQ on helping develop. Kovid's standard reply is: 'Patches welcome"
You need to do the heavy lifting, then submit the patch for review. Remember; Calibre runs on 3 OS

[compurandom]

Originally Posted by theducks

There is a FAQ on helping develop. Kovid's standard reply is: 'Patches welcome"
You need to do the heavy lifting, then submit the patch for review. Remember; Calibre runs on 3 OS

Yes, I'm aware of that. I'm just not comfortable with how to pull in a huge external library for reading pdfs just to get one more metadata item. If I could do more with it than just count toc entries, it might make it worth it. Unless there's something better than pdfinfo already embedded in calibre that I missed...

I'd consider patching the existing pdf metadata reader to get version number at least, except that would require adding a customization hook to it to pick the custom column, and I'm not sure how to do that with an existing standard module either.

[compurandom]

Originally Posted by MarjaE

If I check the individual files in the Mac Finder, command-i can list compatibility level, resolution, security, and encoding software. Maybe Linux or Windows equivalents add color rendering or other info.

Here's the ones that are available via pdfinfo which is what calibre uses to extract metadata from pdfs: (using a random victim pdf I found)

Of these, calibre grabs creator, creation date, modification date (I think), tags (not pictured here).

From your list, I think the only thing missing is encodeing, although this particular pdf may not be interesting enough to exercise all of the possible features.

So, it would be trivial to add those, except that I'm not sure how to assign a custom column to put them in.

Creator:        Adobe InDesign 15.0 (Macintosh)
Producer:       Adobe PDF Library 15.0
CreationDate:   Wed Dec  4 16:01:52 2019 EST
ModDate:        Wed Dec  4 16:03:46 2019 EST
Tagged:         no
UserProperties: no
Suspects:       no
Form:           none
JavaScript:     no
Pages:          220
Encrypted:      no
Page size:      468 x 648 pts
Page rot:       0
File size:      13738051 bytes
Optimized:      no
PDF version:    1.4

[kovidgoyal]

there already is called podofo, use the get_outline() method from calibre.utils.podofo