Is there a way to Convert Jpgs to Webp

[kevn57]

Can Calibre or a Calibre plugin convert jpgs to webp instead of compressing jpgs. I know I can polish losslessly or edit the book to choose compression level but I have software to compress cbz jpg, png files to webp and it really saves lots of space.

I have a 30mb epub, 28mb are the jpg image files, I converted them losslessly to webp format and they're around 3mb.

If Calibre can't do it does anyone know of other software I might d/l to do it?

[DNSB]

One issue is if the software you are using to read your ebooks is able to display WebP images. Most ereaders and quite a few applications I've tried are not happy with WebP images.

For ePub2/3, png, jpg/jpeg, gif and svg are the only supported image formats.

As for that space saving on conversion, my testing has never managed close to the ~90% reduction in file size you show when converting jpb to WebP. The average saved was closer to 25% when I choose to maintain image quality. Oddly, using lossless recompression on the .jpg can give close to the same reduction in size depending on the original image.

[kevn57]

Thanks for the reply

Originally Posted by DNSB

One issue is if the software you are using to read your ebooks is able to display WebP images. Most ereaders and quite a few applications.

I tried Calibre Viewer which is the main software that I use to read epubs with and also SumatraPDF my quick view epub reader and both work with webp images.

As far as image reduction size, I was surprised as well that it was 90% reduction, as I had the compression set to 100%, usually converting CBZ files it'll reduce to about 66% loselessly, but my monitor is 1080p so anything more that that is really a waste.

[BetterRed]

Originally Posted by kevn57

If Calibre can't do it does anyone know of other software I might d/l to do it?

On Windows IrfanView, viz:



BR

[kevn57]

Thanks BetterRed, I know how to convert the images, but then the HTML needs to be edited, I can do it by hand but I have a lot Light Novels that take up a lot of space I was looking for something then can convert images and also update the appropriate files to change the links from ex. pic1.jpg to pic1.webp

I guess not many people care about this because most fiction ebooks don't have a lot of images, maybe that's why no one has automated a solution.

[Quoth]

Originally Posted by kevn57

I tried Calibre Viewer which is the main software that I use to read epubs with and also SumatraPDF my quick view epub reader and both work with webp images.

Desktop viewing is unrelated to eink based ereaders and most apps on iOS and Android. I only use the desktop to check TOC and all links work.

WebP mostly will only work on desktop.

[kovidgoyal]

Just rename all the files in the calibre editor to webp. It will change the links for you. Then use the unpack book tool to replace the renamed files with actual webp images using whatever tool you like.

[kevn57]

Originally Posted by kovidgoyal

Just rename all the files in the calibre editor to webp. It will change the links for you. Then use the unpack book tool to replace the renamed files with actual webp images using whatever tool you like.

Thanks that's just exactly what I wanted.

[kevn57]

Originally Posted by Quoth

Desktop viewing is unrelated to eink based ereaders and most apps on iOS and Android. I only use the desktop to check TOC and all links work.

WebP mostly will only work on desktop.

Thanks, yeah I mostly read on my 1080p TV, through my minipc.

[JSWolf]

How is converting to webp going to make any real difference?

[kevn57]

Originally Posted by JSWolf

How is converting to webp going to make any real difference?

The webp files are much smaller then jpg while same quality.

[Quoth]

Originally Posted by kevn57

Thanks, yeah I mostly read on my 1080p TV, through my minipc.

Why does the file size matter then?
7 year old laptop has 512G
Old Optiplex 7050 mini has 512G SSD and 4T HDD
The 21 year old laptop has 120G + additional 80G added in the spare media bay
New laptop has 256 G SSD and 1T HDD.
My getting old Lenovo Tablet has 256G microSD card.

It's not like putting your entire DVD collection on a mini-PC.

I saw a 6T drive for €155 today.

I'd worry a little about file sizes if it was a PW3 or similar era of 4G only storage ereader. My current eink ereaders are 32G and at about 5,000 ebooks there is still 18.3G byte free.

[JSWolf]

Originally Posted by kevn57

Thanks, yeah I mostly read on my 1080p TV, through my minipc.

webp images are going to make no difference on your TV screen then JPG images. Your webp won't be of any better quality.

Are you that strapped for space that you need every byte you can get?

[theducks]

NAS grade 12T under $200

I upgraded my laptop to 512G SSD for $60

[Quoth]

Originally Posted by theducks

NAS grade 12T under $200

I upgraded my laptop to 512G SSD for $60

Probably nearly €200 + VAT here, but still cheap. A 1/3rd tank of petrol was €20 today and I spent €106 on 11 off 1m x 8mm alloy tubes.

Storage is very cheap now. I remember paying £££ for a 5 MByte HDD for the Apple II