2005.09.23 21:11 "[Tiff] Additional Lossless Compression Schemes", by Frank Warmerdam

2005.09.25 02:54 "Re: [Tiff] Additional Lossless Compression Schemes", by Frank Warmerdam

On 9/24/05, Joris <joris.at.lebbeke@skynet.be> wrote:

It's hard to define 'wide support' in an objective manner. From where I'm standing, it sure does *seem* (=subjective) to be widely supported, though. I now a few attempts at TIFF codec that only support very limited subsets (only uncompressed, or only G3 or G4 compressed, for example), there's also Photoshop using Adobe's code base, and there's a vast amount of apps using LibTiff. The first cannot be expected to support flate compression, but the second and third do.


It is true that I don't have any objective information on breadth of support for deflate. Perhaps I am still think deflate isn't widely supported in TIFF because it wasn't 10 years ago.

Are there any opinions on possibly incorporating LZMA as an additional compression type?

What is the yield? It'll take some time before the new compression mode 'penetrates' the software pool 'out there', so is it worth it? If the yield is just 5% or even up to 15% better compression, I have doubts about this.

I don't really know the yield. Though if it was getting towards 15% that would be quite significant.

Also, note Chris' comments on prediction. Chances are you're using flate compression without prediction, and making this small adjustment could yield considerably already.

To be honest I don't know much about the predictor stuff.

  1. Whether or not this applies to your quest... What is your quest? How did you come to seek better lossless compression, for what application?

I wouldn't really say I'm on a quest. More of an idle query.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent