k2pdfopt: optimizes PDFs for viewing on e-readers

[sunny_hill]

Sure, I'd be happy to send over what I'm trying to convert. Is it possible for me to PM the document to you? I didn't see an option to PM you on your profile page (perhaps my account is too new).

[sunny_hill]

Originally Posted by sunny_hill

Sure, I'd be happy to send over what I'm trying to convert. Is it possible for me to PM the document to you? I didn't see an option to PM you on your profile page (perhaps my account is too new).

Can't edit my post, so replying here. I found a picture that is exactly what I'm seeing. Ignore the red text, the "border" is what I'm seeing on the output PDF.

[Gaaks]

Originally Posted by willus

@Gaaks--it would be most helpful if you could post some examples from the source PDFs that you discussed so that I could try some different options on them.
(Another way would be to send me samples via private message.)

I'm sorry, I ended up completely forgetting about my question here, I actually managed to figure the problem out myself, I'll copy and paste my earlier reply here around spoiler tags to not take so much space.

Spoiler:

Hello Willus, first I'd like to thank you for making this software, it's simply amazing, pretty much all material are in pdf format and k2pdfopt has made some unreadable think on kindle amazing to read.

But I am having problems with photo-copied/scanned material, the kind where there are two pages side by side, I tried using the 2 column feature to split the pages, but I guess that because the scans are low quality the detection isn't working well, some pages get split in the wrong areas and others just don't get split at all.

What I've been doing is, using the crop areas feature and selecting each page, and it works well, the output is in the correct sequence and it treats each crop as it's page, instead of processing the entire image, the problem here is simply that, I can't set a crop for each file, so because of their lack of centering and different sizes, the crop never lines up properly, so I have to do them one by one.

I've also been running into the issue of text getting split in badly centered pdfs, I've been putting -f2p -1 into the additional options like you recommend in the FAQ, but I couldn't the "bp" options in the gui.

And another less common problem is that, there are some high quality color scans, that have the beige color of the page, and the output ends up being grayscale with a gray background which is annoying to read, and I wanted to know if there's a way to make the output monochrome, -bpc 1 sometimes works but the text quality is really, and sometimes the output just comes out completely mangled, I've tried -wt[+] <threshold>, but I think I don't understand how to use that command, because even -wt[+] 0 doesn't output pure white, I was hoping to do something something like -wt[+] 60 since it's a rather dark grey.

I wanted to ask if you have some advice to get better results there, I'm using the GUI version provided on the website.

Turns out that for the -wt option, I was simply using it incorrectly, I was typing "-wt[+]" into the additional options field, instead of "-wt+", so of course the result wasn't what I wanted, after using "-wt+ <threshold>" I could get a good, readable output for my book.

As for my other problems, they aren't related to any specific source pdf files, just questions about the program's usage, for the split text problem -f2p -1 works perfectly, I simply didn't know what the faq meant by "select "bp" from the interactive menu", but as I believe this "bp" option would simply do the same as -f2p -1 I continued using the latter.

And for the crop area feature, the problem is that, although the program can convert multiple pdf files in sequence, you can't have a different crop area setting for each file, so you can't do multiple conversions on pdfs that need cropping in the same instance, and I suppose you wouldn't be able to set additional options for each file either, this isn't a major problem however, as you can simply open multiple instances of the program to convert the files in parallel, I simply wanted to know whether or not there was a way to have a crop setting for each individual file or not, but I don't think I expressed that well in my first reply. But I think that even if you added a feature like that I would end up not using it, as I've read about your program, I came to understand that it is faster to have multiple instances open for multiple file, than it is to convert multiple files on a single instance.

Again, thanks for making this amazing program.

[willus]

Originally Posted by sunny_hill

Sure, I'd be happy to send over what I'm trying to convert. Is it possible for me to PM the document to you? I didn't see an option to PM you on your profile page (perhaps my account is too new).

Yes--that's weird. I haven't noticed that before (that some accounts cannot do PMs). You can go to this page and send me an e-mail. I'll reply back and you can send an attachment. Or you can just send a link.

[willus]

Originally Posted by sunny_hill

Can't edit my post, so replying here. I found a picture that is exactly what I'm seeing. Ignore the red text, the "border" is what I'm seeing on the output PDF.

Does your source file have that same black border, then? If so, you can probably do something like -m 0.25 to get rid of it. That will ignore any marks that are within 0.25 inches of the edge of your document.

[willus]

Originally Posted by Gaaks

Turns out that for the -wt option, I was simply using it incorrectly, I was typing "-wt[+]" into the additional options field, instead of "-wt+", so of course the result wasn't what I wanted, after using "-wt+ <threshold>" I could get a good, readable output for my book.

Ah yes--standard nomenclature for command-line options is to put optional parameters in brackets [ ]. So -wt[+] means that you can use -wt as a command-line parameter and optionally add a + at the end of it, -wt+.

Originally Posted by Gaaks

... I suppose you wouldn't be able to set additional options for each file either, this isn't a major problem however, as you can simply open multiple instances of the program to convert the files in parallel...

Looks like you figured out an efficient way to run k2pdfopt. The best way to do what you want (remember different options for different input files), if you know how to use scripts or batch files, is to create a script / batch file that contains the different k2pdfopt commands for each different file you want to convert. Then they are all saved in the script file and you can run it again if you need to. That is often how I run k2pdfopt, particularly when I want to try various command options but remember what I've tried before.

[Gaaks]

Originally Posted by willus

... The best way to do what you want (remember different options for different input files), if you know how to use scripts or batch files, is to create a script / batch file that contains the different k2pdfopt commands for each different file you want to convert. Then they are all saved in the script file and you can run it again if you need to. That is often how I run k2pdfopt, particularly when I want to try various command options but remember what I've tried before.

Thank you for the advice.

[Tex2002ans]

Originally Posted by willus

Yes--that's weird. I haven't noticed that before (that some account cannot do PMs).

I believe it's only on new users with <5 posts.

Once they pass 5, then they're able to send PMs + edit posts.

It's mostly for spam prevention.

[Dhruva Sambrani]

Output with -n -vb -2 and just -n has weird selection, where there are a lot of "hidden" lines and the whole page gets selected. This isn't that big an issue, but I want to convert it .mobi using calibre's ebook-convert which messes up the output on the converted pdf.

If I use the bitmap output, while the k2pdfopt output is absolutely fine, the mobi version of it is an image of each page, which loses the text selection and resizing and all the flexibility of -n

[willus]

I haven't tried using calibre's mobi conversion utility much, so I'm not familiar with what k2pdfopt settings work best with it. Try adding -ppgs to the k2pdfopt command and see if that doesn't improve the situation. Even turning -n off should still result in a PDF with a selectable text layer, though.

Have you tried loading the PDF into MS Word directly? If you have access to MS Word, that may be a better way to go to convert PDF to mobi. See my web page on the topic.