ISA, kodim01.bmp, others

[ehud]

Hello.

Just found out about your ISA compression on usenet. Good compression and fast encoding does indeed sound interesting... :)

Are you still working on it?

Unlike some other people who have voiced their opinion (on usenet), I wouldn't mind switching to another lossless format if it provides 10% better compression (assuming I can load/save from common viewers/editors).

I tried some other encoders on that kodim01.bmp, here are some results including 3 earlier ones for reference:

Code: Select all

KODIM01.PNG          736,501
kodim01_pngout.png   694,811    PNGOUT
KODIM01.ISA          548,591
KODIM01.JP2          510,320
kodim01.jls          508,753    HP's JPEG-LS
kodim01_rkim_c.rki   489,205    rkim 1.05 c
kodim01_rkim_cx.rki  477,186    rkim 1.05 cx
kodim01_uhic_e.uhi   471,410    uhic 2.0 e
kodim01_uhic_m.uhi   467,110    uhic 2.0 m


Surprisingly JPEG-LS didn't do too well, maybe because the image is small. I tried it on quite a few images (large and larger), and it's always noticeably better than JPEG2000 (wasn't JP2K supposed to be based on JPEG-LS? How did that happen?!), and much faster than any JP2K encoder I know.

UHIC, and certainly RKIM, are rather slow.

Ehud.

[Nils Haeck]

Hello Ehud,

Currently the ISA project is temporarily in the fridge, since I have a lot of other work going on.

There are a few other things I still want to try in order to squeese out more bytes. In that light, I am interested in finding out how the UHIK and RKIM methods work. I assume they're arithmetic coding with a complex predictive model. That's one of the areas where the ISA format can still gain a lot.

Thanks for the interest!

Nils

[Nils Haeck]

For everyone interested, I have put up an executable demo online that contains the ISA compressor and decompressor. It is also able to save as TIFF, JP2, BMP and PNG.

It can compare two images and pinpoint even the smallest changes, in order to compare if two images are identical.

Please note: the ISA compressor may fail on images that have dimensions that are not a multiple of 8.

In the archive you will also find some of Kodak's test images in PNG format.

Link:
http://www.simdesign.nl/download/IsaCompress.zip

Kind regards,

Nils Haeck

[Guest]

Hi again.

I tried the compressor. Is there a way to change the compressor parameters? Each of the 4 sample PNGs converted to ISA yields a larger file.

Also, it tries to create quadruo.txt in a fixed directory (c:\\temp...) instead of the program path.

BTW: Is the project still in the fridge? :)

Ehud.

[Nils Haeck]

Hello Ehud,

The project had a little bit of attention, but basically, for another application. So concerning still image compression, it is still in the fridge.

Indeed, this exe creates a text file for debug purposes (I forgot to uncomment), in folder \"C:\\Temp\\Planes\\\". So you probably need that folder if you want to test. I'll upload a new compile without this if I have time.

When I convert the sample PNG's I get this:

Directory of C:\\Temp\\TestConvert

Code: Select all

09/02/2004  01:15a             515,365 kodim01.isa
02/02/2004  09:24p             736,501 kodim01.png
09/02/2004  01:15a             459,727 kodim02.isa
02/02/2004  09:25p             617,995 kodim02.png
09/02/2004  01:15a             408,121 kodim03.isa
02/02/2004  09:25p             502,888 kodim03.png
09/02/2004  01:15a             469,242 kodim04.isa
02/02/2004  09:25p             637,432 kodim04.png


So the ISA files are clearly smaller than the PNG files.. Is this not what you get?

Kind regards,

Nils

[Guest]

Hey Nils,

Previously you got kodim01 to 548K, and now you're at 515k. That is a nice improvment, but somehow I get this:

Code: Select all

Loaded in  219 ms: \"kodim01.png\" (  736501 bytes)
Saved  in 2940 ms: \"kodim01.isa\" (  787563 bytes)
Loaded in  305 ms: \"kodim02.png\" (  617995 bytes)
Saved  in 2710 ms: \"kodim02.isa\" (  688973 bytes)
Loaded in  216 ms: \"kodim03.png\" (  502888 bytes)
Saved  in 2444 ms: \"kodim03.isa\" (  603517 bytes)
Loaded in  320 ms: \"kodim04.png\" (  637432 bytes)
Saved  in 2725 ms: \"kodim04.isa\" (  697439 bytes)
Total images loaded in   1.1 s, total size    2494816 bytes (100.0%)
Total images saved  in  10.8 s, total size    2777492 bytes (111.3%)


Maybe some library dependency, or CPU specific code?

Ehud.

[Nils Haeck]

Hmm that's really weird. Everything required for the ISA coder is included in the EXE. The other dll files in the folder are used for JPeg2000 and TIFF, so ISA does not depend on them.

Can you decode the ISA files? What about the other formats, or when you save to PNG again?

Is your file system trying to compress files in any way?

Can you try it on another computer? I run Windows 2000. I will also test this on XP.

Kind regards,

Nils

[Guest]

Didn't I answer already? Odd, I remember I did... nevermind. :)

The ISAs decode fine to the exact same BMPs the PNGs decode to.

Of course there's no compression. Does anyone use realtime compression nowadays (did anyone EVER use it?)? :)

I only have Win98 computers, I suppose they would all be the same, but how can this be an OS issue?

Ehud.

[Nils Haeck]

When I run the ISA compressor, I get this output:

If anyone gets something else, then *please* let me know, because then some very strange machinedependent things are happening. I'd also be interested in getting a confirmation of the same results.

When comparing ISA and PNG afterwards, the files are pixel-perfect (no differences in pixels, not even one bit).

Nils

[ehud]

Hey again.

Is there a newer build since last year, or is http://www.simdesign.nl/download/IsaCompress.zip still the most up to date?

Testing with this EXE I got the same results as last time -- size increase.

Ehud.