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serious bug: iView not supporting .jpg spec

 
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Dimitri



Joined: 25 Jul 2007
Posts: 3

PostPosted: Sat Jul 28, 2007 9:03 pm    Post subject: serious bug: iView not supporting .jpg spec Reply with quote

iView has an issue which needs to be addressed. It doesn't support all the jpeg photo formats, as a result, it totally screws colors.

Take an example of this photo:
http://s135598769.onlinehome.us/cycling.jpg

Feed it into iView 3.1.3 and see if it can render it properly. Every conceivable software running under Windows XP can render this image, browsers, Explorer, Photoshop, etc, BUT NOT iView!

The results of this image would be like this screenshot:
http://s135598769.onlinehome.us/screen.jpg

OK, now, what's the bug/problem one may ask?
The problem is that iView ALWAYS assumes - by totally ignoring the jpeg headers - the jpeg format. It always assumes that the jpeg image is in the YCbCr colour-space with sub-sampling.

The image above, is NOT YCbCr with color sub-sampling: It's an RGB JPEG without color sub-sampling!

I understand that iView is geared towards professionals. And many times, Professionals desire Hi-Fi color - and would rather avoid color sub-sampling. Anyhow, if amateur or my grandpa's software can render this image properly, by properly reading the jpeg headers as of what the jpeg is all about, I don't' see a reason or understand why iView Media ignores all the crucial information in the JPG header where the type and order of image components are defined. In the header, nine bytes give component ID, horizontal and vertical sampling frequency and quantization table number for all three components.

I only tested this with jpegs. I don't know if iView also ignores headers for other filetypes such as TIFs or CMYK files. If it's the case, then the issue becomes even more serious. Color management, essentially, goes up in smoke.

FYI: There are 3 types of Jpegs:
1. YCbCr color-space, CbCr color sub-sampling (what iView always assumes);
2. YCbCr color-space, no color sub-sampling; and
3. RGB color space (the above image).

Google for more info or go here:
http://stereo.jpn.org/eng/stphmkr/anaglyph/anaglyph.htm

This is an issue that needs to be adressed.

Dimitri Papadopoulos
Montreal, Canada
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roberte



Joined: 18 Jun 2004
Posts: 2147
Location: Sydney, Australia

PostPosted: Sat Jul 28, 2007 10:58 pm    Post subject: Reply with quote

Hi Dimitri,

iView and the current version of xMedia rely on QuickTime to render most file formats. Most serious DAM apps do (Portfolio, Cumulus, Fotoware) and you have identified a limitation of that.

As I suggested in your post on Canon TIF RAW files, lodge a user suggestion. The Expression Media team are as receptive to user suggestions as the iView team were, probably more so.
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-- Robert
Expression Media 2 / Windows 8 / Mac OS X 10.10
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Dimitri



Joined: 25 Jul 2007
Posts: 3

PostPosted: Sun Jul 29, 2007 2:00 am    Post subject: Reply with quote

Robert,

Thanks for your quick reply. I just posted an updated version of the RGB JPEG file, this time also with full IPTC/XMP metadata headers, thus mimicking a real-world professional workflow:

http://s135598769.onlinehome.us/cycling.jpg

In case the Microsoft/iView/Exression team doesn't has quick access to an 11 Megapixel Canon 1Ds Camera RAW TIF to fiddle with, here it is:

http://s135598769.onlinehome.us/1ds.tif

(don't worry about the white border, the CCD is giving signs that it wants to retire after working hard for many many years, and traveling the world 5 times with a press/sports photographer...)

PS. I fed the "problematic" RGB JPEG file into Fotoware Photostation 5.2 and it rendered it ok. I also fed it with the 1Ds raw tif, and it gave me a full-screen preview. I'm not arguing the fact that iView might be sharing the same Quicktime decoder as Photostation, but from what I see, the 2 major issues raised here, (RGB-JPEG & 1Ds previews) don't appear in Photostation.

I'm confident that the Expression team would want to take a closer look at this before releasing the final version. Other than that, iView is able to handle 95% of my files, which, on a positive note: it's good.

Best,

Dimitri Papadopoulos
Montreal, Canada
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moonmoon



Joined: 14 Feb 2008
Posts: 7

PostPosted: Mon Mar 10, 2008 12:45 pm    Post subject: Reply with quote

i gain.it's good.
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