Seeking DNG SDK Assistance

[deejjjaaaa]

and your note about color (=.dcp camera profile) profiles basically means that any "color" transforms  (from camera's RGB numbers to ACR's internal working space) are happening after demosaicking as well, hence no matter what do you do and how do you create a profile (with or without Adobe's DNG PE - even if you type it yourself manually and compile using Sandy's DCP compiler/decompiler) it will not affect the demosaick itself (in camera's own RGB numbers, that what "the fundamental demosaic results" actually means)...

PS: about BayerGreenSplit tag - why this is not user accessible parameter ? I saw a numbers of cases when people long after ACR version release send you a sample raw file for you to correct maze artefacts... isn't it more simple to put it somewhere in UI in a camera calibration tab for example ?

[Nigel Johnson]

...not by crippled /as Eric said/ DNG converter code...

Eric did NOT say that the DNG Converter used a bilinear interpolation demosaic routine, rather he stated that the DNG SDK used the simpler routine. Hence he did NOT say that the DNG Converter code was crippled.

Regards,
Nigel

[deejjjaaaa]

Eric did NOT say that the DNG Converter used a bilinear interpolation demosaic routine, rather he stated that the DNG SDK used the simpler routine. Hence he did NOT say that the DNG Converter code was crippled.

Regards,
Nigel

let us just hope that Eric will clarify that, because I am pretty sure that in another topic it was said by him that DNG converter (not public DNG SDK) was using not the same demosaick as ACR/LR... 

[sandymc]

Short summary:

ACR/LR > DNG converter > DNG SDK

 

Sandy

[deejjjaaaa]

Short summary:

ACR/LR > DNG converter > DNG SDK

 

Sandy

exactly... I am at work now and I can't find a reference to the Eric's post, but hopefully I will...

[Nigel Johnson]

Short summary:

ACR/LR > DNG converter > DNG SDK

Sandy,

This is not what Eric says, see the following quote (note that the bold text is my highlighting and not in the original message):

Yes, DNG is a documented image file format (basically an extension of TIFF) that can be used by anybody, but there have been revisions to it since its introduction. Just like there are multiple versions of JPEG, TIFF, MPEG, etc.

Yes, the DNG Converter will allow you to process a new raw image in an older version of ACR.

It is true that the public DNG SDK only contains a simple bilinear demosaic implementation, but the DNG Converter does not use this.

For operations that require a demosaic step (e.g., conversion to 3-channel RGB), DNG Converter uses the same demosaic algorithm as Camera Raw, assuming the same version. For example, DNG Converter 6.2 and Camera Raw 6.2 use the same demosaic algorithm. Similarly, DNG Converter 4.4 and Camera Raw 4.4 use the same (older) demosaic algorithm. Newer versions of DNG Converter offer more camera support, have bug fixes, and improved features over earlier versions. For this reason, I generally recommend using the latest available version of DNG Converter (currently 6.2, soon to be 6.3), regardless of which version of Camera Raw you are using.

Regards,
Nigel

[deejjjaaaa]

Sandy,

This is not what Eric says, see the following quote

and I was not referring to that quote, which deals w/ SDK - but to another topic completely ( probably @ http://forums.adobe.com/community/cameraraw )

[Nigel Johnson]

and I was not referring to that quote, which deals w/ SDK - but to another topic completely ( probably @ http://forums.adobe.com/community/cameraraw )

The quote deals with both the SDK and with the DNG Converter and Camera Raw (the second bold highlight). I accept that you may have another quote from elsewhere.

Nigel

[deejjjaaaa]

The quote deals with both the SDK and with the DNG Converter and Camera Raw (the second bold highlight). I accept that you may have another quote from elsewhere.

Nigel

Again I might be wrong - the subject that was discussed (I am pretty sure that was later then the quote from this topic) is if Adobe DNG converter use the exact ACR/LR code when creating a preview in DNG file and the only difference between DNG converter and ACR/LR is that DNG Converter will create a JPG file (so you can't controll compression options, color space, etc) but everything else - demosaick, NR, local edits, etc - everything is the same - so you can remove preview from DNG file, take DNG converter and if you have xmp or the same embedded in DNG file then you can recreate that preview exactly as ACR/LR 'd do... and I was guessing that yes, indeed and I am pretty sure that Eric Chan said - no, demosaick (at least) is not the same... again I can't find a quote at the moment - but I am just trying to explain the context of discussion back then.

[deejjjaaaa]

I am happy to report that I was wrong and my memory failed me  !

http://forums.adobe.com/message/4725070#4725070

I believe that's a miscommunication.  The DNG Converter does use the same demosaic processing as ACR/LR (assuming matching version).  It's the public DNG SDK that uses a different (simpler) demosaic processing.

Yes, producing a linear DNG, then re-loading that DNG into ACR and processing it, will produce the same results, assuming all the relevant metadata is intact.