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2011.03.29 20:17 "LibTIFF compression enhancements", by Stephan Busch
Dear Thomas, it has been a while since we last talked. I suggested a new lossless code for usage within your TIFF library. Neither PackPNM nor the popular JPEG2000 has been implemented by now. Today I also want to suggest a new codec. It is fast. It is free. It is open-sourced. BCIF by Stefano Brocchi http://www.dsi.unifi.it/users/brocchi/ The caveat is that it supports 24-bit color images only by now. The author would be interested in adding BCIF to your TIFF library. What do you think? Looking forward to your answer Regards, Stephan ________________________________________________________________________ > Hi, >> So far I haven't heard of any TIFF libraries that use jpeg2000 algorithm= s, >> but its sad that all those maintainers could not agree to use a unified= =20 >> version all libraries could read. > I'm not quite clear what you mean by that. JPEG2000 is standardized, and > if TIFF tags for J2K are specified, you should be able to include it.=20 > However, I probably don't see the point. J2K defines its own file=20 > format, avoiding typical TIFF problems like the 4GB barrier, thus I=20 > wonder why anyone would want to do that. >> LOCO-I is the algorithm behind JPEG-LS. It was designed a decade ago by= =20 >> HP Labs, >> gives better compression than jpeg2000 in most cases and there are many= =20 >> implementations; >> some of them are open-sourced such as: >> www.stat.columbia.edu/~jakulin/jpeg-ls > While I certainly agree for lossless compression, just a note: Please do > not use the above implementation, it has a bug in bit depths > 8 and=20 > creates files that do not conform to the specs - it's an endian issue=20 > that can be easily fixed, but that is nevertheless there. > JPEG-LS is certainly a nice tiny codec that shouldn't take up too much > time to implement (hopefully then correctly) but are there TIFF tags for = it? >> In the case neither jpeg2000 nor jpeg-ls are implementable, I wanted to= =20 >> suggest >> another codec that will be free and open-sourced soon. The algorithm is= =20 >> called PackPNM at present >> and it performs like jpeg-ls. > I have never seen or heard about this one. I would prefer algorithms=20 > that are openly available, actually. >> Also, in my opinion only the codec that you will chose might survive.=20 >> All high performance image codecs >> have been designed but were never implemented for practical use.=20 > What do you mean by that? JPEG-LS and JPEG 2000 have been implemented=20 > for practical use for sure. > So long, > Thomas Stephan Busch