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TOPIC: WebP format

Re: WebP format 4 years 3 months ago #36150

  • statikcat
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I created a copy of the same book using webp and original jpeg. I put them side by side in comicrack and quickly compare by using the next/previous book command. This way you can instantly flip between the two versions. I compared several pages. On my Dell 24" 1080p monitor I can see no difference in quality. The Comicrack webp conversion does add so very slightly to the darks but not in a bad way. The image lines and quality look identical. I did this test at work but I want to also check on my 47" TV at home to get a closer look. I am interested in converting my entire library. This particular comic reduced over 50% in size!

Should it be expected to receive no quality loss in this conversion? I am not a digital artist with a "professional" eye but I have always had a knack for quality but I don't want to totally trust my judgement before converting my lib. I don't plan on doing it right away but it is tempting. I could fit my stuff on a ssd with reduced size.

Also, I read lossless is coming in the next version. If there is no quality loss.. does this even matter? Wouldn't it just add more size for no gain? Would it mostly help in converting again in the future? Thanks!
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Re: WebP format 4 years 3 months ago #36151

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On second look there appears to maybe be a slight blur effect on webp compared to the source. Mostly noticeable on a panel with say a wall texture it appears slightly blurred. Anyone else do comparisons .. what results did you find?
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Re: WebP format 4 years 3 months ago #36153

  • jkthemac
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my experience on the iPad:

if the comic is painted or has a grain to the image I am getting really quite bad compression artefacts with the new version. It was bad enough for me to return to non-compressed images for all of my synced lists for now, which proves to be a battery drain. I also found that text is far less sharp.

I have always been very sensitive to such things so YMMV.

Is there a way to adjust the compression rate for syncing in the ini file? Perhaps the compression is too aggressive?
Last Edit: 4 years 3 months ago by jkthemac.
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Re: WebP format 4 years 3 months ago #36157

  • cYo
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See ComicRack.ini
You can set compression and size and also switch back to jpg if you do not like webp.
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Re: WebP format 4 years 3 months ago #36161

  • wolmerian
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Hey guys, I was wondering if anyone has had success viewing webp comics in Android. I have a Nexus 7 running Android 4.3 and the ComicRack app will not show webp images (I am using v1.77). I am able to view the files perfectly on my windows laptop but when I sync them to my tablet the comics can't be viewed.
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Re: WebP format 4 years 3 months ago #36168

  • jkthemac
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cYo wrote:
See ComicRack.ini
You can set compression and size and also switch back to jpg if you do not like webp.

Cool, I assumed it would be there but haven't had time to check it out. At some point I'll play with the compression and feedback if there is a happy compromise for more texture laden images.

---Edit
To clarify, having quickly checked the ini, I presume you are referring to the standard SyncOptimizeQuality setting. Is this applied regardless of jpg or webp?

Also, I notice that in the Export Books Script the Quality can't be changed for Webp, is this something that might change in later versions?
Last Edit: 4 years 3 months ago by jkthemac.
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Re: WebP format 4 years 3 months ago #36169

  • jkthemac
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I have been having a play with the Telegraphis webP plugin for photoshop to see what my ideal webp settings would be and it looks like the key setting is the filtering profile.

When set to Strong the textures get smoothed out, and the artefacts around high contrast areas such as text become pronounced.
When set to none the textures remain and the artefacts are comparable to jpg.

The standard settings for CR seem to be using the Strong Profile.

There is also no difference in file size for these options, so it would seem that control over this setting would be ideal, or at least a default to Filtering Profile None.
Last Edit: 4 years 3 months ago by jkthemac.
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Re: WebP format 4 years 3 months ago #36204

  • vc4u
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First of all a BIG THANKS to support WebP, it has drastically reduced my library collection size.

But I found an issue with WebP conversion and re-conversion back to JPEG from a WebP Comics CBZ file.

Now I was successfully able to convert my original comics to WebP, but when I try to convert this WebP comics to usual CBZ with JPEG images (I've created settings with JPEG format files):



The resulted CBZ file does not have image files changed to JPEG but it still have WebP files. As if an export to desired format has not at all carried out. Though the export process took normal time to convert the file and no errors at all in the process.
Last Edit: 4 years 3 months ago by vc4u.
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Re: WebP format 4 years 3 months ago #36207

  • cYo
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Thank you for this find.
Yes, there's a bug converting WebP back to jpeg. I'll put the fix in the next release (which I hope will be released today).
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Re: WebP format 4 years 3 months ago #36208

  • vc4u
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cYo wrote:
Thank you for this find.
Yes, there's a bug converting WebP back to jpeg. I'll put the fix in the next release (which I hope will be released today).

Thank you cYo :cheer:
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