Filter Forge - JPEG quality is mediocre when saving from stand-alone mode

uberzev

not lyftzev

Posts: 1890
Filters: 36

This isn't a huge issue but I hate to have to go into photoshop everytime I wanst to share an image I've made.

FF JPEG at 80 quality (24kb)...

PS JPEG at 80 quality (10kb) ...

Posted: June 18, 2006 9:17 pm

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Kraellin

Kraellin

Posts: 12749
Filters: 99

uberzev, yup. this is one i'd like also. if the 'save image' on the user side calculated the file size in bytes and displayed that when the .jpg compression slider came up, it would help immensely.

craig

If wishes were horses... there'd be a whole lot of horse crap to clean up!

Craig

Posted: June 18, 2006 11:00 pm

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onyXMaster

Filter Forge, Inc.

Posts: 350

uberzev: PS does not have the 0-100 image quality scale, was that "10" on their quality scale you assumed to be 80?

Posted: June 19, 2006 12:22 am

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onyXMaster

Filter Forge, Inc.

Posts: 350

Also please attach original filter for our tests smile:)

Looks like you want chroma downsampling disabled -- it will make better edges, but certainly won't make image smaller. As for comparing with Photoshop -- the image loading/saving is options are merely a convenience and entirely dependent on external libraries. Looks like IJG libjpeg isn't producing files small enough, we'll look into it, but won't promise making files smaller.

Posted: June 19, 2006 12:30 am

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uberzev

not lyftzev

Posts: 1890
Filters: 36

Quote
onyXMaster wrote: uberzev: PS does not have the 0-100 image quality scale, was that "10" on their quality scale you assumed to be 80?

I don't think I did that...

Here's a screenshot of Photoshop's "Save for the web" dialog...

I may be mistaken but it apears to me that FF outputs JPEGS of lower quality and greater file size than Photoshop does. I understand if this isn't a major priority, there are work arounds.

Posted: June 19, 2006 12:35 am

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uberzev

not lyftzev

Posts: 1890
Filters: 36

Test filter...
http://uberzev.googlepages.com/JPEGQualityTest.ffxml

JPEG from FF...

TIFF from FF...
http://uberzev.googlepages.com/BASE.tif

JPEG from PS (with TIFF from FF as source)...

Posted: June 19, 2006 12:53 am

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onyXMaster

Filter Forge, Inc.

Posts: 350

Aahh, Save for Web... smile:)

No, we won't be able to reach the sizes of Photoshop's "Save for Web..." without spending at least a month on JPEG research. I really doubt that we'll work on it in near future.

We may work on quality improvements though, like adding a checkbox "Preserve color contrast" on the JPEG saving dialog in FF, which will reduce the color blurred artifacts on color contrast borders.

Posted: June 19, 2006 2:03 am

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onyXMaster

Filter Forge, Inc.

Posts: 350

Also, in your last example, the Photoshop file is two times larger than Filter Forge one (although I agree that quality of FF image is inferior to PS one -- see my previous message).

Posted: June 19, 2006 2:04 am

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Vladimir Golovin
Administrator

Posts: 3446
Filters: 55

Zev, I suspect that Adobe uses some sort of "pre-conditioning" on Photoshop images before feeding them into JPEG compressor.

Also, Adobe's JPEG quality slider is likely limited so that it doesn't allow to set the actual JPEG quality to zero (Corel's compressors allow that). Probably the lowest we can get in Photoshop is around 20-25%.

Posted: June 19, 2006 7:21 am

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rilos

rilos

Posts: 88
Filters: 9

oh, there's really a big difference ?
Does the same problem occur when you use 100% jpg-Quality in FF ?
Its easy to compress the results a bit in Postwork via an action in PS e.g.
I normally you 90 - 98 % Quality when saving images in FF - didnt try it out yet compared to 100 %.

regards, rilos

Posted: June 19, 2006 7:23 am

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uberzev

not lyftzev

Posts: 1890
Filters: 36

A JPEG saved at maximum quality still shows unsightly artifacts. I'd really like to see this get resolved.

FF max quality 16kb...

PS max quality 17kb...

Posted: June 19, 2006 7:36 am

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onyXMaster

Filter Forge, Inc.

Posts: 350

See the attached image for the newly implemented color contrast preservation flag. The produced images are somewhat larger, but the quality is comparable to Photoshop ones. There will be a checkbox in the JPEG options form to enable this compression mode. Turning off dithering in Tools->Options also helps to reduce the artifacts.