[Digikam-devel] idea: "make digikam trustworthy" metabug

[Sebastian Roeder]

> Subject: [Digikam-devel] [Bug 115168] digikam: camera download: Unlike
> other rotation in the program (thanks to kipi), auto rotate is LOSSY
>
> *** This bug has been marked as a duplicate of 117115 ***

Issues like described in this bug report are from my point of view an SERIOUS
PROBLEM!

I know that Gilles is working towards an PNG workflow for digikam but as
discussed earlier there might be a) people that want to stick to jpg for
various reasons (online printing services, DVD player compatibility and such)
and b) from my point of view digikam users must at least have the chance to
KNOW when actions applied to there photos are lossy. From my point of view
that is at the moment not clear or distigishable in digikam without knowing
the internals of the program.

So my idea is to collect bug reports towards this topic (things in digikam
happen lossy without giving the user enough feetback about this at least) in
a meta bug.

I will do the job when the feetback here is possitive.

Again, for me this is realy important issue cause I don't want to store all my
pictures with a program I can not trust - realizing one day that the picture
qality was seriously descrised without informing me about. I would say
improving digikams trustworthyness is the most important thing after fixing
crashes.

Btw I am in the process of building the tarballs for digikamimageplugins right
now.
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Op zaterdag 4 februari 2006 22:20, schreef Sebastian Röder:
> > Subject: [Digikam-devel] [Bug 115168] digikam: camera download: Unlike
> > other rotation in the program (thanks to kipi), auto rotate is LOSSY
> >
> > *** This bug has been marked as a duplicate of 117115 ***
>
> Issues like described in this bug report are from my point of view an
> SERIOUS PROBLEM!

If the solution is a one liner, we would have done it.

Toma

> I know that Gilles is working towards an PNG workflow for digikam but as
> discussed earlier there might be a) people that want to stick to jpg for
> various reasons (online printing services, DVD player compatibility and
> such) and b) from my point of view digikam users must at least have the
> chance to KNOW when actions applied to there photos are lossy. From my
> point of view that is at the moment not clear or distigishable in digikam
> without knowing the internals of the program.
>
> So my idea is to collect bug reports towards this topic (things in digikam
> happen lossy without giving the user enough feetback about this at least)
> in a meta bug.
>
> I will do the job when the feetback here is possitive.
>
> Again, for me this is realy important issue cause I don't want to store all
> my pictures with a program I can not trust - realizing one day that the
> picture qality was seriously descrised without informing me about. I would
> say improving digikams trustworthyness is the most important thing after
> fixing crashes.
>
> Btw I am in the process of building the tarballs for digikamimageplugins
> right now.
> _______________________________________________
> Digikam-devel mailing list
> [hidden email]
> https://mail.kde.org/mailman/listinfo/digikam-devel

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[Gilles Caulier-2]

Le Samedi 4 Février 2006 22:20, Sebastian Röder a écrit :
> > Subject: [Digikam-devel] [Bug 115168] digikam: camera download: Unlike
> > other rotation in the program (thanks to kipi), auto rotate is LOSSY
> >
> > *** This bug has been marked as a duplicate of 117115 ***
>
> Issues like described in this bug report are from my point of view an
> SERIOUS PROBLEM!

None action from IE are lossy like with JPG !

1 / you load the image to decode JPEG data. In memory we working on RAW image
data. There is _NO_ compression !!!

2/ When you save the image in a JPEG file, you reencode it and you have a risk
to lost any image quality. JPEG is a suck file format to correcting photos !

3/ To limit this problem with JPEG, you need to put JPEG quality setting to
max value.

Gilles
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> Le Samedi 4 Février 2006 22:20, Sebastian Röder a écrit :
> > Issues like described in this bug report are from my point of view an
> > SERIOUS PROBLEM!

I would like to second Gilles.

First a comment to rotation and JPG: Every better photoviewer supports the
EXIF rotation flag. So if you use or can correct the rotation flag there is
no need to have an active rotation or a special jpeg lossless rotation (that
digiKam also supports, when it knows the filetype) at all.

The only thing you have to know when working with digiKam is, that when you
use the IE you work with raw picture data like in every other graphic editor
(e.g. gimp, krita, cinepaint, photoshop) The problem is not a limitation of
the IE - its the other way round. If the IE could only manipulate JPGs I
would not use digiKam any longer.

You use the wrong format - its simple as that. You have to understand that JPG
is an im- & export format. Do not use it in a complex workflow if you have
high quality demands. JPG as a lossy format is designed for transport - that
why you can find it in every camera and every photo web service. Its minimize
the level of storage and bandwidth. These are  expense factors for digicams
and web services. But when it come to quality you will not find jpeg any
longer, then RAW, Tiff and PNG rules.

But you really see a visual difference when watching JPEGs written with 99%
quality settings from the IE?

I also think there is one limitation with JPEG and IE: The quality setting
should be visible and adjustable in the "save as" dialog when using a lossy
file format. The simple save comand is dangerous. I hear too often that
people lose image details cause they used to use a 65%-75% default JPEG
quality setting for web and slideshows.

Bye

  Thorsten

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[Sebastian Roeder]

> I would like to second Gilles.
>
> First a comment to rotation and JPG: Every better photoviewer supports the
> EXIF rotation flag. So if you use or can correct the rotation flag there is
> no need to have an active rotation or a special jpeg lossless rotation
> (that digiKam also supports, when it knows the filetype) at all.
>
> The only thing you have to know when working with digiKam is, that when you
> use the IE you work with raw picture data like in every other graphic
> editor (e.g. gimp, krita, cinepaint, photoshop) The problem is not a
> limitation of the IE - its the other way round. If the IE could only
> manipulate JPGs I would not use digiKam any longer.
>
> You use the wrong format - its simple as that. You have to understand that
> JPG is an im- & export format. Do not use it in a complex workflow if you
> have high quality demands. JPG as a lossy format is designed for transport
> - that why you can find it in every camera and every photo web service. Its
> minimize the level of storage and bandwidth. These are  expense factors for
> digicams and web services. But when it come to quality you will not find
> jpeg any longer, then RAW, Tiff and PNG rules.
>
> But you really see a visual difference when watching JPEGs written with 99%
> quality settings from the IE?
>
> I also think there is one limitation with JPEG and IE: The quality setting
> should be visible and adjustable in the "save as" dialog when using a lossy
> file format. The simple save comand is dangerous. I hear too often that
> people lose image details cause they used to use a 65%-75% default JPEG
> quality setting for web and slideshows.
>
> Bye
>
>   Thorsten

Sorry if my post was unclear - I did NOT want to change how digikam works
internal and it is OK for me to accept that jpg image saving is lossy in IE
due to the jpg file format.

What I want to improve is to give the user more feetback about it - with
tooltips, improved dialogs and so on. The idea of the meta bug was to collect
ideas in which areas this improvements can happen.

When I got the internals right, then in Album mode all manipulations even to
jpg are lossless thanks to file format specific kipi plugins that incorporate
jpeg lossless. So there must be NO exeption of this rule (I started this post
as a reaction of the auto rotate not lossless bug report). I hope this is the
only exeption and that it will be fixed soon. Stiil I see the need to tell
the user in an clever way that Album mode is were he should do things like
rotate images (cause if he does it in IE and saves to jpg it's lossy!).

Second area to improve is as already mention by you the save dialog in IE.
Here one might e.g. preselect PNG as default format to save manupulations and
drop a warning of the lossyness when the user changes it to jpg. This is what
I mean by "trusworthyness" - giving the user more feetback about what digikam
does with the images, thus making the internals more transparent to the user
(or let me say the digikam design approach) without forcing the user to study
the internals in (technical) detail.

I must admit I do not have the time to do this work in the next two weeks or
so, I'd like e.g. to talk to the usability people about it. But I will work
on it as soon as possible. As a preparation from my point of view collecting
ideas on where this omprovements can tale place is  a good thing (TM).  
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