2004.12.13 13:54 "Re: [Tiff] TIFF Pyramid", by Eric Vergnaud

In the first image IFD, the SubIFDs tag is set with value 3, and that yields a file with one main (biggest) image and 3 downsample SubIFDs. If I change the value 3 of the SubIFDs tag to e.g. 2, it works as expected, one main image is written, 2 SubIFDs are linked to that main image, and the last is again written as a top-level IFD.

I just noticed, it doesn't actually produce a SubIFD chain, but a SubIFD array. Meaning, the first SubIFD doesn't point to the second etc, but all SubIFDs are directly pointed to from the SubIFD tag.

I do think that's uncommon, but it's valid, I think, according to the specification supplement that described SubIFDs tag.

Ok, I'll have a look at this in the next few days and let you know.

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