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gen2brain / cbconvert

CBconvert is a Comic Book converter
GNU General Public License v3.0
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What does quality option do? #20

Open rohitghali opened 9 months ago

rohitghali commented 9 months ago

I'm trying to convert stuff into avif. Tried with quality value 10, 90 and 100. It's the same file size and no difference in visual quality. Am I missing something? What does it even do?

gen2brain commented 9 months ago

It affects JPEG, WEBP, AVIF, and JXL. You have a comparison table in the README, a quality of 70 is like 56 for AVIF. As ImageMagick is used for AVIF and JXL, their conventions must be accepted, i.e. with a quality of 100 lossless option is enabled. For small images, you should not see immediate results in the preview, but 0 or 10 should show something, i.e. for JPEG at least. I used a quality of 50 to convert some comics to AVIF and I am very satisfied with the size/results.

rohitghali commented 9 months ago

I think I found the issue. It doesn't work on the latest version. It does on the older ones.

gen2brain commented 9 months ago

The older version used libheif directly, now it is used via ImageMagick which is built with libheif, and the quality settings is applied in MagickWand the same as is for other formats.

rohitghali commented 9 months ago

Yep. Works in 0.9.1. Doesn't work in 1.0.0. Literally no change in quality and size. I'm using command line BTW.