search for: waechtler

Hi everybody, I wrote last time some code to do video compression using a 3d integer wavelet transform. Since it uses a reversible lifting scheme and avoids a lot of floating point operations compared to Jacks initial Tarkin code, this should be somewhat faster and allow lossy+lossless compression. The current implementation is very experimental, but nevertheless I would be happy if some of you

Hi, I uploaded a new tarball to http://www.informatik.hu-berlin/~waechtle/w3d-0.1.21.tar.gz. The command line argument format has changed, it now expects a byterate/frame and a filename format string like "%i.ppm". Beside this I have added some minor changes in the coefficient transmission code. Please take a look on it, Jacks cat is only slightly blurred even at 1kB/frame -- the

Hi Lourens, I fixed the YUV conversion and added a 'skip-empty-bitplanes' feature. The latter is still buggy, I have to check this again. But images look mach better now, even if you use higher compression ratios. (try ./main 1500 150 150 for a 352x288 image -- the output becomes blurred, but how does it looks when you compress it using jpeg down to about 2kB ...). Source is available

Hi Ralph, could you please set up a area at xiph.org, where you mirror some of the test sequences, just to be shure that everybody talks about the same sequence ? The license issues are not too important, I think if we should be allowed to use 'free for non-commercial use' sequences for our tests. Perhaps it's a good idea to seperate things in 'free', 'free for test

Hi everyody, ince some of you asked for references, here some links: A good book is 'Data Compression' from David Salomon, ISBN 0-387-98280-9. Papers available on the web: A nice introduction to wavelets is http://cm.bell-labs.com/who/wim/papers/athome/ A somewhat theoretical paper about integer wavelet transform http://cm.bell-labs.com/who/wim/papers/integer.ps.gz Since Peter