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NiLuJe · 07-31-2012, 07:29 PM

@mo79: Ah, it's indeed in Calibre's FAQ

.

Technically, the key here is not so much the personal document stuff, but the fact that there's an ASIN specified in the exth headers (there isn't one when kindlegen builds a mobi, but Calibre adds a 'fake' one to support Syncing, among other things). If there is, Amazon assumes the file comes from them, and will try to use it to get the corresponding thumbnail from their servers. If it's bogus, it fails horribly

.

The fact that K4PC/Mac/Android think files without an ASIN are PDOCs is another thing entirely. If you just happened to mark a calibre file with an ASIN as pdoc (through the cdetype exth header), it would still fail to show a thumbnail, although it technically is marked as a PDOC (not sure how K4PC would sort such files, but the e-Ink devices correctly mark them as pdocs).

07-31-2012, 07:29 PM	#4
NiLuJe BLAM! Posts: 13,506 Karma: 26047202 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	@mo79: Ah, it's indeed in Calibre's FAQ . Technically, the key here is not so much the personal document stuff, but the fact that there's an ASIN specified in the exth headers (there isn't one when kindlegen builds a mobi, but Calibre adds a 'fake' one to support Syncing, among other things). If there is, Amazon assumes the file comes from them, and will try to use it to get the corresponding thumbnail from their servers. If it's bogus, it fails horribly . The fact that K4PC/Mac/Android think files without an ASIN are PDOCs is another thing entirely. If you just happened to mark a calibre file with an ASIN as pdoc (through the cdetype exth header), it would still fail to show a thumbnail, although it technically is marked as a PDOC (not sure how K4PC would sort such files, but the e-Ink devices correctly mark them as pdocs).