AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

1999.10.14 14:55 "TIFF Version validation", by Bill Comstock
1999.10.15 00:33 "Re: TIFF Version validation", by Tom Lane
1999.10.15 17:20 "Re: TIFF Version validation", by Thomas E Deweese
1999.10.16 05:04 "Re: TIFF Version validation", by Jaya krishnan Chathu
1999.10.16 22:00 "Re: TIFF Version validation", by Michael L. Welles

1999.10.15 17:20 "Re: TIFF Version validation", by Thomas E Deweese

>>>>> "TL" == Tom Lane <tgl@sss.pgh.pa.us> writes:

>> I'm interested in putting a large collection of TIFF images through
>> a validation process, one that tests each image against a series of
>> rules and reports whether it conforms to the TIFF standard [...]

A more useful way to look at things is a profile of features required to decode any particular TIFF --- for example, if your program said "tiled TIFF using LZW compression and containing 24-bit RGB data", that would convey helpful information. You can't usefully boil it down to "version 5.0" (or whichever spec release was the first one to mention all of those features), because almost no decoder supports the *whole* spec of any release.

Admittedly talking about 'versions' of Tiff is not real correct (I prefer to talk about 'flavors', but profiles also works). But a good tool to at least validate baseline Tiff files would, I think, be very useful. If the tool could check the validity some of the more common profiles, tiled, alpha channels, extra samples, alternate color spaces - 'inks support', various compression sets, would be really welcome.

I think that many of us have had the experience of reading the TIFF spec. and doing our darn best to implement to what it says, but over looking this or that little detail, and always wondering if we were writing out subtlety 'corrupt' Tiff files.

--
                                                        Thomas DeWeese
deweese@kodak.com
                        "The only difference between theory and practice is
                         that in theory there isn't any." -- unknown