I would appreciate it if somebody, perhaps @hannoschwalm, can clarify what is now really the situation with demosaicking in DT.
In the FAQ on darktable.org one can find:
"What happened to the demosaic module in darkroom? How can I select more demosaicing algorithms?¶
We moved the demosaicing into our internal pixel pipeline. The benefit is that it is faster and more accurate. The downside is that we have to implement the demosaicing algorithms ourselves. Since the differences are really small with real world photos we didn’t bother to port more than PPG and AMaZE. If anyone feels the need for more choice we will gladly accept patches."
I interpret this as there should still be a choice between alternative algos somewhere, but I cannot find it. In the demosaic module PPC or AMaZE is not included in the methods drop-down menu – but I can find VNG that in the 4.6 manual is listed together with PPC or AMaZE and others as available demosaicking algos. Neither can I find any relevant settings in Preferences. I cannot find anything in the release notes since v. 4.6 (latest updated manual info on demosaic module) that sheds any light on this.
Does “moved the demosaicing into our internal pixel pipeline” mean that demosaicking does not take place within the execution of the demosaic module? – is it in the initializations that take place prior to the pixelpipe is set to run?- 'If so what does that mean for e.g. the raw denoise module that according to the v. 4.6 manual performs denoising on raw image data before it is demosaicked?
even from my user perspective, lots of things have changed between DT 4.6 and the current 5.2.
“Internal pixel pipeline” means a module you cannot switch on or off, as you need them anyway. That’s why they have their own icon. Other examples include e. g. input and output color spaces.
In addition, this 2 year old thread you cited sees performance just as execution speed. I do care more about noise, sharpness and colors. Anyway, DT 5.2 demosaicing algos are as below:
That FAQ entry should probably be removed entirely. I don’t know the story, but it seems the demosaic module was removed at some point, only to be reinstated later.
That said, I did put it in the “Very Old Versions” section for a reason, when I redid the FAQ recently.
Aaaah, now that I see the methods menu you post, which is quite different from that I saw, a penny drops and I realize what it was that made me so confused.
I looked at the options in demosaic module after just opening up a random image I had downloaded from PlayRaw.
That happened to be captured with a Fuji camera, so I would guess that DT in that case just displays what I’ll believe is algo alternatives for X-Trans sensors only …
Then things fall into place and I can die in piece.
Wasn’t demosaic always there - was it ever an option to deactivate it?
Anyhow, I have never registered the term "internal " used to describe the part of the pixel pipe where module activation is outside user control, so that clarification was a bonus.
Yes, I think it is a good idea to remove it - this thread is a proof that it is just confusing. What you tell about the removal of demosaic, makes it somehow understandable, though.
And with my own realization of what the situation really is, the info in the 4.6 manual gives meaning to me again.
