Bloated epub file sizes?

[theducks]

Originally Posted by Joques

I'll just put the cursor where I want the split, hit ctrl-return, and the split happens.

I do that one a bunch.

I also use S&R to place the Sigil split marker (made by ctrl-Shift-enter) so I can check it out before pressing F6

Different strokes

[JSWolf]

Seems nobody cares that you can lower the size of the ePub by reducing some of the crud in the graphics without changing the quality of the graphics at all.

[HarryT]

Originally Posted by JSWolf

Seems nobody cares that you can lower the size of the ePub by reducing some of the crud in the graphics without changing the quality of the graphics at all.

If you reduce the size of a JPEG file you are discarding information. The result may look very similar, but it's incorrect to say that you're not "changing the quality of the graphics at all". Having said that, you can discard a LOT of information from a JPEG file without noticeably changing its visual appearance.

[Jellby]

Originally Posted by HarryT

If you reduce the size of a JPEG file you are discarding information. The result may look very similar, but it's incorrect to say that you're not "changing the quality of the graphics at all".

Some changes can be lossless, if done correctly with the correct tool: Discarding metadata, optimizing compression, removing color information in greyscale images (not exactly lossless, but lossless in practice), cropping extra margins...

[JSWolf]

Originally Posted by Jellby

Some changes can be lossless, if done correctly with the correct tool: Discarding metadata, optimizing compression, removing color information in greyscale images (not exactly lossless, but lossless in practice), cropping extra margins...

The method I mentioned edits the jpeg information without changing the pixels. The result is possibly a smaller file with no loss of quality. For example, Photoshop is known to put stuff in the jpeg file that can be stripped out without any loss to the image. An iPhone can put in location information that can also be stripped out. There's a lot of junk in there that's not needed and just makes the file size larger.

[j.p.s]

Originally Posted by Jellby

Some changes can be lossless, if done correctly with the correct tool: Discarding metadata, optimizing compression, removing color information in greyscale images (not exactly lossless, but lossless in practice), cropping extra margins...

jpegtran can also losslessly flip and rotate.

[JSWolf]

Originally Posted by j.p.s

jpegtran can also losslessly flip and rotate.

I do like the idea of reducing the image sizes without changing the image at all. This does work well.

[Joques]

Originally Posted by JSWolf

Seems nobody cares that you can lower the size of the ePub by reducing some of the crud in the graphics without changing the quality of the graphics at all.

I mean, I am sure there's a lot of bloat to cut here, but in practice going through all my books and dicking with the image files is frankly never going to happen :-)

[JSWolf]

Originally Posted by Joques

I mean, I am sure there's a lot of bloat to cut here, but in practice going through all my books and dicking with the image files is frankly never going to happen :-)

Then obviously, the file size of your ePub doesn't matter to you. So why start this thread if that's the case?

[shalym]

Originally Posted by JSWolf

Then obviously, the file size of your ePub doesn't matter to you. So why start this thread if that's the case?

Because he was curious about the why of the different sizes?

Originally Posted by Joques

I am curious, and a quick search on the forum didn't yield an answer:

Why is the so little correlation between the length of a book and its file size? I am not talking about books containing lots of pictures here, just formatted text in a regular novel. One book of average length might weigh in at 400kB, while another, of similar length and also having no images in there, might be 2,5 MB.

What is it that bloats these file sizes so?

Shari

[Joques]

Thank you, Shalym :-)