I found some information after a lot of googling! I now have some sample data that makes sense.
Quick summary: Using data from the definition to the A302 TIFF Tag: The value consists of: - Two short, being the grid width and height of the repeated pattern. - Next, for every pixel in that pattern, an identification code. This identification code can be: 0 = Red 1 = Green 2 = Blue 3 = Cyan 4 = Magenta 5 = Yellow 6 = White and now looking at some data extracted from some TIFF files: TIFF Tag(33421) 0x828d Type(3) ushort(2) ISO CFARepeatPattern: 2 2 TIFF Tag(33422) 0x828e Type(1) ubyte(4) ISO CFAPattern: 0x00010102 EXIF Tag(41730) 0xa302 Type(7) undef(8) CFAPattern: 0x0002000200010102 It all begins to make sense. Thanks David From: Sulau <su...@freenet.de> Sent: 06 April 2023 22:24 To: 'David C. Partridge' <david.partri...@perdrix.co.uk> Cc: tiff@lists.osgeo.org Subject: RE: [Tiff] TIFF/EP I see. I can try to compile some easy understandable sample code for you to explain how to write and read those tags using LibTiff. But I have to take a closer look at the tags myself first. Maybe after Easter. I cannot say anything about their "interpretation" (i.e. meaning). Von: David C. Partridge [mailto:david.partri...@perdrix.co.uk] Gesendet: Donnerstag, 6. April 2023 21:36 An: tiff@lists.osgeo.org <mailto:tiff@lists.osgeo.org> Cc: 'Sulau' <su...@freenet.de <mailto:su...@freenet.de> > Betreff: RE: [Tiff] TIFF/EP A302 is an EXIF tag with the same name as 828E (CFAPattern). I know all three are defined in the source code (grep for CFA). My concern is sample code to guide me to interpret them correctly. Thanks David From: Sulau <su...@freenet.de <mailto:su...@freenet.de> > Sent: 06 April 2023 19:58 To: 'David C. Partridge' <david.partri...@perdrix.co.uk <mailto:david.partri...@perdrix.co.uk> > Cc: tiff@lists.osgeo.org <mailto:tiff@lists.osgeo.org> Subject: RE: [Tiff] TIFF/EP Dear David, there is an initial merge request (see https://gitlab.com/libtiff/libtiff/-/merge_requests/337). However, there are some issues at this stage. I was preparing an improvement at the time. I could update it and then upload it to my repository. From there you could get it and try it. Would that help? CFARepeatPatternDim (828D) and CFAPattern (828E) are define, but what is the tag-definition of A302? Regards, Su Von: Tiff [mailto:tiff-boun...@lists.osgeo.org] Im Auftrag von David C. Partridge Gesendet: Donnerstag, 6. April 2023 14:39 An: tiff@lists.osgeo.org <mailto:tiff@lists.osgeo.org> Betreff: [Tiff] TIFF/EP Is there any support in 4.5.0 for TIFF/EP? Does anyone know of any sample code that reads/processes/writes (e.g.) CFARepeatPatternDim (828E) and CFAPattern (828E or possible A302). Thanks David
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