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TOPIC: Lossless File Size Reduction

Lossless File Size Reduction 3 years 4 months ago #39999

  • JesseCuster
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  1. Both jpegtran and pngcrush are free or open source. It would be great if there was an option during export to use them as both are able to losslessly optimize images and work from the command line. If using pngcrush, there should be an additional option to use the -brute prameter (it takes a lot of time but in most of the cases is the only way to successfully reduce the size of a PNG).

  2. When renaming of the image files is chosen (which may be argued as being "lossy" anyway) it would be better if the number of digits would match the highest number of images. An archive with 28 images named P00001 to P00028 is actually bigger than an archive with the same images numbered P01 to P28. (Ok, I know I'm fighting for single bits here ;) )

  3. The ComicInfo.xml could spare a few bytes by removing line feeds and empty spaces between tags. If anyone really wants to manually edit this file he or she could use an editor that is capable of tidying up the source.
Last Edit: 3 years 4 months ago by JesseCuster. Reason: typo
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Lossless File Size Reduction 3 years 3 months ago #40264

  • romsnesrom
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JC, I am very curious about the bottomline here. How much are we gaining jpegtranning our comics? Are we talking single digits savings or more?
Last Edit: 3 years 3 months ago by romsnesrom.
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Lossless File Size Reduction 3 years 2 months ago #40275

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That depends.

Some comics seem to have been reduced already, I'd say about the half of them, so there is no gain at all.

The other half is usually 2% to 3% smaller after using jpegtran. But I also found some that could be reduced by 10% to 30%.
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Lossless File Size Reduction 3 years 2 months ago #40277

  • romsnesrom
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I understand that the biggest advantage of JPEG lossless optimization is that it retains compatibility while saving space (and believe me I am in favor of anything that saves space), but I found out that (within my limited sample size) I could gain much more space using ZipX compression instead of ZIP. The main shortcomings of Zipx are that it is not mainstream and it is closed. Maybe it could get the same treatment as RAR has today in CR. I already started converting my comics to Zipx and I use Honeyview (which is not bad by a long shot) to read them, but I wish someday CR can support it.
Have you tried Zipx, JC?
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Lossless File Size Reduction 3 years 2 months ago #40393

  • JesseCuster
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romsnesrom wrote:
Have you tried Zipx, JC?

So far I haven't, as it is a Corel proprietary format, but I will have a look at it.

romsnesrom wrote:
I am in favor of anything that saves space

Same here. Unfortunately I'm stuck with plain old CBZ format because my tablet is my favorite reading device for comics and ComicRack is my favorite reading software (neither CBR nor CB7 are fully supported on Android).

How does Zipx compare to 7zip?
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Lossless File Size Reduction 3 years 2 months ago #40407

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In my testing 7zip is very near vanilla Zip when it comes to compressing JPEGs. ZipX can reduce the filesize losslessly around 20%. I read comics in my computer, so it is easier for me, but my workflow is:

1 - convert CBRs to CBZs
2 - use CR to sort and organize everything into folders (and add some XML tags in case it gets supported by CR in the future)
3 - convert CBZs to ZipXs
4 - Read them in Honeyview

Not very straightforward, but current disk space is very tight for my collection.
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Lossless File Size Reduction 3 years 2 months ago #40408

best option to have lossless comicarchives with comicrack is WEBP in lossless mode
not png and not jpg but i dont know which qualitysetting results in lossless
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Lossless File Size Reduction 3 years 2 months ago #40416

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oX, how much gain can we expect converting our CBZs full of JPEGs to CBZs full of WebPs?
Last Edit: 3 years 2 months ago by romsnesrom.
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Lossless File Size Reduction 3 years 2 months ago #40442

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OK, I tested it myself, and while I do not think it is a fair scenario for WebP, I think it is the scenario we should test.

Converting JPGs to WebPs in lossless mode in maximum compression resulted in an INCREASE in size of around 380%

I realize that the ideal scenario would be saving primary sources in WebP and then comparing, but our archives are already in JPEG and that is what we are trying to optimize losslessly.
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Lossless File Size Reduction 2 years 2 weeks ago #43922

  • -oX-
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it exist only one format its free and is better then webp
to compress lossless - its FLIF

but the problem - comicrack use very old webp-algorythm
and dont know FLIF -

here a realistic test about lossless compressing with different formats
flif.info/
Last Edit: 2 years 2 weeks ago by -oX-.
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