Page flip direction gone when converting PRC to AZW3

[esagi]

Hello,
I'm trying to convert a PRC file to AZW3.
When viewed on the kindle app for android, the original PRC page flip direction is right to left (the book is in Hebrew).
When converting to AZW3, the page flip is reset to the default latin languages behavior.
The only other change to the file that I did is embeddeing Tahoma font.

Please advice, thank you very much.

[kovidgoyal]

That's not a PRC book, it is already an AZW3 book, Just rename it.

[kovidgoyal]

And converting the attached file gives me an azw3 with the page-progression-direction correctly set in the spine of the OPF.

[esagi]

Thank you for the reply - I did as you suggested and simply renamed the prc file to azw3.

However, any change to the file "breaks" the right to left page progression.
The page-progression-direction still correctly set on the OPF, but the kindle app ignores it and flips the pages left to right.
(changing the metadata from Calibre main menu is alright)

Attached are 3 files:
"Metadata title change only.azw3" - the original prc file renamed, works OK
"Metadata title change and single word change.azw3 " - edited a single work in the text, doesn't work
"With font embbeded.azw3" - embedded fonts, doesn't work

I tried comparing all of these file and didn't see any difference that should matter, without any success. Any idea what should I do?

Thank you very much

[kovidgoyal]

In that case it is likely there is some other proprietary bit in the azw3 file that needs to be set -- unfortunately the only way to figure that out is via reverse engineering and I dont have the time for it right now.

If you are technically inclined you can dump the contents of the azw3 file using

calibre-debug file.azw3

do it for the before and after files and see if you can spot any significant differences

[kovidgoyal]

I took a aquick look and there is one obvious EXTH header field being removed, this should fix it: https://github.com/kovidgoyal/calibr...2e2724ae041b0d

but as I said I dont have the time to test it properly just now.

[esagi]

Just to be clear - you mean running a conversion and adding the debug option, and then looking at the files generated at the "input" folder?

[kovidgoyal]

No, just running

calibre-debug file.azw3


It will inspect the azw3 and output detailed info about its internal structures.

[esagi]

Update: no info gained from the output files.
The work around was converting the prc\azw3 to epub and embedding the desired fonts, and then using kindlegen convert the epub to mobi(kf8).
Right to left works now, and the embedded font (would have tried it earlier, but I thought mobi didn't support embedded fonts).

Thanks anyway for the reply

[pdurrant]

It will be worth trying again in a week or two with the latest version of calibre to see if the fix Kovid's just added to the calibre code does the trick.