Category Archives: wavelet

Wavelet Image Compression

bitbucket

I finally got around to a) updating my old WordPress-installation (after finding out spam-bots had already created custom folders on my installation) and b) uploading all my public code to bitbucket (as Mercurial repositories). That includes my wavelet image compression … Continue reading

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Wavelet 3.4.0

A slightly bigger release, which brings two major changes. Not compatible with older files due to the the reorder-changes. The improvements to bit.c are not terribly well tested. More here, as usual. As an aside, Kompressor is now served in … Continue reading

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It’s wavelet bugfix time — 3.3.4 is here!

While compressing a multi-channel file with a target bitrate and no specific target MSEs the resulting bit distribution between the channels seemed rather odd, and comparing the results to an older version revealed that it was indeed totally bogus! So … Continue reading

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Darcs Repository

Thanks to PHPDarcsView (which is very useful if you are on a hosted server where you are unable to run darcs itself) you can now browse the Wavelet-repository online; the official documentation and Kompressor.app are still here.

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Kompressor.app and Wavelet Image Compression Library 3.3.3

Shortly before the year is out (and as result of my vacation), there is some fresh software to be had… I’ve now written an Mac OS 10.4 application called Kompressor.app to compress, inspect and display WKO images. This release goes … Continue reading

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Rate-Distortion Graph

I’ve invested a bit of time in getting some nice rate-distortion graphs out of my wavelet image compression library. Now that it’s embedded, the process is fairly easy: Compress once into a single file and then decompress only enough bits … Continue reading

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Wavelet 3.2

As I’ve taken a two-day vacation pre-easter, I’ve gotten some more work done on my Wavelet Image Compression Library (and not played games as some of my colleagues were led to believe ). Before this version all the subbands of … Continue reading

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Wavelet 3.1

Another week, another release of my Wavelet image compression. I figured out how to do complete embedding, which justifies another release. This means you can compress an image once, and then get different rates by simply truncating that file! The … Continue reading

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Wavelet 3.0

I’ve been steadily working on my wavelet image compression for the past few weeks, and in the process have improved it in many ways. These are largely not technical improvements, but rather a huge code refactoring, the creation of decent … Continue reading

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Hilbert Curve

I’ve been reading a bit about the spacefilling curves for my wavelet image compression (take a look here and here). There is a very nice way to convert from the Hilbert derived key to (multi-dimensional coordinates) described by John J. … Continue reading

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Better Wavelets

Another update to the wavelet-code (now standing at 2.7). This one is INCOMPATIBLE with older versions and will crash them. The new version has lots of failsafes and should be “immune” towards new versions and corrupt data (if the header … Continue reading

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Time Allocation is a difficult Problem

Been busy optimising the wavelet-code (but not really getting anywhere… hand-made assembly for the bit-encoding gains 20-30% max). Even busier playing “Ikaruga” and “Animal Crossing” (US Import as it probably won’t come out in Europe)…

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