This is deprecated. Take a look in the w3d/docs directory. The command line semantics are changed. You have to call the test program now like this: ./tarkin_enc ../clips/venuscubes-ppm/AnimSpace00%03d.ppm 5000 4 4 ./tarkin_dec ------------------------------------------------------------------------------ Hi, this is a experimental 3d-integer-wavelet-video compression codec. Since the integer wavelet transform is reversible and a reversible rgb-yuv conversion is used (you can understand it as (1,2) integer wavelet transform, too), this codec should be lossless if you transmit the whole bitstream. The Y/U/V-bitstreams are embedded, thus you can simply get lossy compression and shape the used bandwith by cutting bitstreams, when a user defined limit is reached. Here is how the current code works: First we grab a block of N_FRAMES frames (defined in main.c) of .ppm files. Then each pixel becomes transformed into a YUV-alike colorspace. Take a look in yuv.c to see how it is done. Each component is then transformed into frequency space by applying the wavelet transform in x, y and frame direction. The frame-direction transform is our high-order 'motion compensation'. At boundaries we use (1,1)-Wavelets (== HAAR transform), inside the image (2,2)-Wavelets. (4,4)-Wavelets should be easy to add. See wavelet.c for details. The resulting coefficients are scanned bitplane by bitplane and runlength-encoded. Runlengths are Huffman-compressed and written into the bitstreams. The bitplanes of higher-frequency scales are offset'ed to ensure a fast transmission of high-energy-low-frequency coefficients. (coder.c) The huffman coder is quite simple and uses a hardcoded table, this can be done much better, but I wanted to get it working fast. Decompression works exactly like compression but in reversed direction. The test program writes for each frame the grabbed original image, the y/u/v component (may look strange, since u/v can be negative and are not clamped to the [0:255] range), the coefficients (look much more like usual wavelet coefficients if you add 128 to each pixel), the coefficients after they are runlength/huffman encoded and decoded, the y/u/v components when inverse wavelet transform is done and the output image in .ppm format. You can call the test program like this: $ ./main 20000 5000 5000 ../clips/%i.ppm which means: images are grabbed from directory ../clips/0.ppm, ../clips/1.ppm, etc. The Y component bitstream is limited to 20000 Bytes, the U and V bitstreams to 5000 Bytes. If the last argument is omitted, frames are taken from current directory. Good Luck, - Holger