[gdal-dev] JasPer vs OpenJPEG performance

[Even Rouault]

Le lundi 10 août 2015 14:58:59, Jukka Rahkonen a écrit :
> Brad Hards <bradh <at> frogmouth.net> writes:
> > On Fri, 7 Aug 2015 11:17:56 AM Jukka Rahkonen wrote:
> > > NITF requires either that the tile size must not be
> > > bigger that 1024x1024, or that the whole file is written as one single
> > > tile. I believe you have such single-tile NITF file.
> > 
> > I don't believe this is true (at least in NITF 2.1 - MIL-STD-2500C) for
> > two reasons:
> > 1. Tiling is mandatory above 8192 x 8192 (See Table A-10 Complexity Level
> 
> 7 or
> 
> > higher)
> > 2. Tiles are allowed to be up to 2048 x 2048 (Complexity level 3) or 8192
> > x 8192 (Complexity level 5 or higher).
> 
> Hi Brad,
> 
> I read the NITF 2.1 - MIL-STD-2500C
> http://www.gwg.nga.mil/ntb/baseline/docs/2500c/2500C.pdf in the same way
> than you do. However, I wrote my comments after reading another (older)
> document:
> "NATIONAL IMAGERY TRANSMISSION FORMAT (NITF) VERSION 2.1 COMMERCIAL DATASET
> REQUIREMENTS DOCUMENT (NCDRD)"
> http://www.gwg.nga.mil/ntb/baseline/docs/stdi0006/NCDRD_18February2010.pdf
> 
> And especially part
> 2.3.2	JPEG 2000 Image Geometry Segmentation
> Commercial datasets shall be organized in JPEG 2000 tiles as described in
> BPJ2K01.00 Section 8.
> 
> I believe that the referred document is this:
> http://www.gwg.nga.mil/ntb/baseline/docs/bpj2k01/ISOJ2K_profile.pdf
> 
> Appendix C  JPEG 2000 Commercial Profiles (ISO/IEC IS 15444-1
> Annex A.10)  , Table C-1. Codestream Restrictions:
> 
> Profile-0:
> Tiles of a dimension 128x128:
> YTsiz=XTsiz=128
> or one tile for the whole
> image:
> YTsiz+YTOsiz>=Ysiz
> XTsiz+XTOsiz>=Xsiz
> 
> Profile-1
> XTsiz/min(XRsiz, YRsiz)<=1024
> XTsiz=YTsiz
>  or one tile for the whole image:
> YTsiz+YTOsiz>=Ysiz
> XTsiz+XTOsiz>=Xsiz
> 
> 
> It may be that tiling is mandatory for images bigger than 8192 x 8192
> because of the baseline standard. On the other hand is seems that
> commercial vendors are not allowed to use multiple tiles if they are
> larger than 1024 x 1024. I did not dig too deep into the black hole
> between 1024 x 1024 and 8192 x 8192.

Nice hunt through standards ;-)

If the image is tiled, no issue.

Found in the documents you mentionned :
- http://www.gwg.nga.mil/ntb/baseline/docs/bpj2k01/ISOJ2K_profile.pdf at 
paragraph 9.2.1.2 Tiling "It is recommended that the image be tiled with
in a JPEG 2000 codestream."
- http://www.gwg.nga.mil/ntb/baseline/docs/bpj2k01/ISOJ2K_profile.pdf at 
paragraph 8.1 "The following JPEG 2000 parameter choices are recommended [...] 
Images are tiled with JPEG 2000 at a tile size of 1024x1024"

So I think that the single-tile scheme that is theoretically possible by the 
Profile-1 of the JPEG2000 standard is not to be used in JPEG2000 compressed 
NITF.

Looking at a NITF sample from a commercial provider, I can see it uses 
1024x1024 tiles for example.

Even

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