[OSGeo-Discuss] Open File FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]

[Michael P. Gerlek]

Yes, JP2 supports signed and unsigned types of up to ~24 bits.  And lots of channels (bands).  And alpha masking.  And arbitrary metadata blobs (geospatial and otherwise).

-mpg


-----Original Message-----
From: discuss-bounces at lists.osgeo.org [mailto:discuss-bounces at lists.osgeo.org] On Behalf Of Lucena, Ivan
Sent: Friday, August 21, 2009 12:22 PM
To: OSGeo Discussions; OSGeo Discussions
Subject: RE: [OSGeo-Discuss] Open File FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]

But you can't compress data types other than byte in JPG. Can you do that in JP2K?


>  -------Original Message-------
>  From: Landon Blake <lblake at ksninc.com>
>  Subject: RE: [OSGeo-Discuss] Open File	FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]
>  Sent: Aug 21 '09 12:42
>  
>  Paul,
>  
>  I was wondering the same thing.
>  
>  It seems a little like choosing to drive a Honda Accord, or a Ferrari.
>  The Ferrari is a lot faster and comes with a better looking trophy wife
>  (or husband), but the Honda is a lot easier to fix. (Try finding an
>  affordable Ferrari mechanic in Stockton, California.)
>  
>  To tie this back into our original discussion, it seems like the
>  government should be choosing to drive a Honda Accord when it can,
>  instead of the Ferrari.
>  
>  I guess you'd really have to crunch the numbers and see if the savings
>  in bandwidth/disk space costs were really worth the compression savings
>  that result from a proprietary compression scheme ("wavelet black
>  magic").
>  
>  The problem with this is a lot of the benefits that come from the Honda
>  Accord (open image format + open compression algorithm) aren't easily
>  calculated in dollars and cents.
>  
>  Still, this speaks to an important truth I have discovered in open
>  source development: Simple is better, even when it isn't necessarily
>  faster and smaller.
>  
>  I'd rather have code that I can understand, or a file format that a
>  programmer in 20 years will understand, than a Ferrari you can't drive
>  unless you have a PHD and did a thesis on wavelet compression. :]
>  
>  Landon
>  Office Phone Number: (209) 946-0268
>  Cell Phone Number: (209) 992-0658
>  
>  
>  
>  -----Original Message-----
>  From: discuss-bounces at lists.osgeo.org
>  [mailto:discuss-bounces at lists.osgeo.org] On Behalf Of Paul Ramsey
>  Sent: Friday, August 21, 2009 10:36 AM
>  To: OSGeo Discussions
>  Subject: Re: [OSGeo-Discuss] Open File
>  FormatsandProprietaryAlgorithms[SEC=UNCLASSIFIED]
>  
>  So hung up on wavelets, we are.
>  
>  Internally tiled TIFF with JPEG compression and similarly formatted
>  internal overviews can achieve 10:1 compression rates without
>  noticeable image quality reductions, and as an added bonus can be
>  decompressed a heck of a lot faster than wavelet-based formats. The
>  wavelet stuff is k00l, in that there is no need for an overview
>  pyramid (it's implicit in the compression math) and much higher
>  compression rates can be achieved. But operationally, you can go a
>  long way with the more primitive (open image format + open compression
>  algorithm) approach.
>  
>  P.
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