PDF to PDF corruption

PoP · 09-10-2011, 10:22 AM

After Calibre added a particular PDF to the library (no conversion asked, just adding) the added PDF can't be opened in Acrobat Reader which complains the file is corrupt.

Acrobat Reader can open the original source PDF with no problem.

I conclude that Calibre does not simply copy the source PDF to its library (along with creating additional metadata) but rather does some kind of conversion (PDF to PDF).

This has happened to just a few of my PDFs. I can't figure out any special oddness in this specific PDF, other than it is rather large (45MB).

I am respectfully wondering... shouldn't Calibre just copy exactly from the source when adding to the library?

kovidgoyal · 09-10-2011, 10:29 AM

It does just copy files. Compare file sizes of the two files, or run a md5 hash on them to verify this.

PoP · 09-10-2011, 10:48 AM

The file sizes are different.

Source PDF = 44.8 Mb (46,980,499 bytes)
Added PDF = 45.0 Mb (47,259,648 bytes)

PeterT · 09-10-2011, 11:01 AM

By any chance do you have any of the DRM removal plugins installed? If so, that might be the problem.

PoP · 09-10-2011, 11:07 AM

Of course, I should have thought about that. Let me try without these plugin. I'm quite sure this will correct the problem.

PoP · 09-10-2011, 11:12 AM

Yep, problem was caused by the plugin and Calibre is clean. Sorry for bothering you Kovid. You can erase my PM too.

09-10-2011, 10:22 AM	#1
PoP curly᷂͓̫̙᷊̥̮̾ͯͤͭͬͦͨ ʎʌɹnɔ Posts: 3,002 Karma: 50506927 Join Date: Dec 2010 Location: ♁ ᴺ₄₅°₃₀' ᵂ₇₃°₃₇' ±₆₀" Device: K3₃.₄.₃ PW3&4₅.₁₃.₃	PDF to PDF corruption After Calibre added a particular PDF to the library (no conversion asked, just adding) the added PDF can't be opened in Acrobat Reader which complains the file is corrupt. Acrobat Reader can open the original source PDF with no problem. I conclude that Calibre does not simply copy the source PDF to its library (along with creating additional metadata) but rather does some kind of conversion (PDF to PDF). This has happened to just a few of my PDFs. I can't figure out any special oddness in this specific PDF, other than it is rather large (45MB). I am respectfully wondering... shouldn't Calibre just copy exactly from the source when adding to the library?

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09-10-2011, 10:29 AM	#2
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	It does just copy files. Compare file sizes of the two files, or run a md5 hash on them to verify this.

09-10-2011, 10:48 AM	#3
PoP curly᷂͓̫̙᷊̥̮̾ͯͤͭͬͦͨ ʎʌɹnɔ Posts: 3,002 Karma: 50506927 Join Date: Dec 2010 Location: ♁ ᴺ₄₅°₃₀' ᵂ₇₃°₃₇' ±₆₀" Device: K3₃.₄.₃ PW3&4₅.₁₃.₃	The file sizes are different. Source PDF = 44.8 Mb (46,980,499 bytes) Added PDF = 45.0 Mb (47,259,648 bytes)

09-10-2011, 11:01 AM	#4
PeterT Grand Sorcerer Posts: 12,167 Karma: 73448616 Join Date: Nov 2007 Location: Toronto Device: Nexus 7, Clara, Touch, Tolino EPOS	By any chance do you have any of the DRM removal plugins installed? If so, that might be the problem.

09-10-2011, 11:07 AM	#5
PoP curly᷂͓̫̙᷊̥̮̾ͯͤͭͬͦͨ ʎʌɹnɔ Posts: 3,002 Karma: 50506927 Join Date: Dec 2010 Location: ♁ ᴺ₄₅°₃₀' ᵂ₇₃°₃₇' ±₆₀" Device: K3₃.₄.₃ PW3&4₅.₁₃.₃	Of course, I should have thought about that. Let me try without these plugin. I'm quite sure this will correct the problem.

09-10-2011, 11:12 AM	#6
PoP curly᷂͓̫̙᷊̥̮̾ͯͤͭͬͦͨ ʎʌɹnɔ Posts: 3,002 Karma: 50506927 Join Date: Dec 2010 Location: ♁ ᴺ₄₅°₃₀' ᵂ₇₃°₃₇' ±₆₀" Device: K3₃.₄.₃ PW3&4₅.₁₃.₃	Yep, problem was caused by the plugin and Calibre is clean. Sorry for bothering you Kovid. You can erase my PM too.