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TIFF and LibTiff Mail List Archive

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2010.06.21 21:49 "Re: LibTIFF compression enhancements", by Stephan Busch
2010.06.22 13:46 "Re: [Tiff] Fwd: Re: LibTIFF compression enhancements", by Thomas Richter

2010.06.22 13:46 "Re: [Tiff] Fwd: Re: LibTIFF compression enhancements", by Thomas Richter

Hi,

So far I haven't heard of any TIFF libraries that use jpeg2000 algorithms, but its sad that all those maintainers could not agree to use a unified 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. However, I probably don't see the point. J2K defines its own file format, avoiding typical TIFF problems like the 4GB barrier, thus I wonder why anyone would want to do that.

LOCO-I is the algorithm behind JPEG-LS. It was designed a decade ago by HP Labs, gives better compression than jpeg2000 in most cases and there are many 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 creates files that do not conform to the specs - it's an endian issue 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 suggest another codec that will be free and open-sourced soon. The algorithm is called PackPNM at present and it performs like jpeg-ls.

I have never seen or heard about this one. I would prefer algorithms that are openly available, actually.

Also, in my opinion only the codec that you will chose might survive. All high performance image codecs have been designed but were never implemented for practical use.

What do you mean by that? JPEG-LS and JPEG 2000 have been implemented for practical use for sure.

So long,

Thomas